Method and apparatus for MRO mechanism for SPAR or SPCR and SCG fault information procedure

Abstract

The present disclosure relates to a method and apparatus for a mobility robustness optimization (MRO) mechanism for PSCell addition success reporting (SPAR) or PSCell modification success reporting (SPCR) and SCG failure information procedures. According to one embodiment, a UE includes a processor and a transceiver coupled to the processor, the processor is configured to: receive configuration information related to a PSCell addition or modification procedure from a MN via the transceiver, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to a successful completion of the PSCell addition or modification procedure; and transmit the assistant information via the transceiver to at least one of a MN, a source SN, or a target SN in response to the successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition.

Description

[Technical Field]

[0001] Embodiments of the present application generally relate to wireless communication technologies, and in particular to a method and apparatus for a mobility robustness optimization (MRO) mechanism for a primary cell of a secondary cell group (PSCell) successful PSCell addition report (SPAR) or successful PSCell change report (SPCR) of a secondary cell group and a secondary cell group (SCG) failure information procedure. [Background technology]

[0002] A base station (BS) may have several cells (or areas) to provide communication services. A handover procedure is performed when a user equipment (UE) moves from a serving cell of a source BS to a target cell of a target BS. If a radio link failure (RLF) or handover (HO) failure occurs to the UE, the UE may perform a radio resource control (RRC) re-establishment procedure. The UE may access the cell through a successful RRC re-establishment procedure. The accessed network requests UE information including the UE's RLF report, so that the network can optimize mobility issues based on the UE information from the UE. Therefore, the UE sends a failure report to the network.

[0003] The MRO mechanism is to detect connection failures that occur due to premature or late handover, or handover to the wrong cell. The typical procedure is for the UE to access a new cell through an RRC re-establishment or connection setup procedure after an RLF or HO failure occurs. When the UE enters the connected state, it sends an RLF report and a RACH report to the serving cell. The serving cell sends a failure indication containing the RLF report to the previous serving cell. Finally, the information is used to optimize mobility.

[0004] The 3rd Generation Partnership Project (3GPP®) 5G network is expected to increase network throughput, coverage, and robustness, and reduce latency and power consumption. With the development of the 3GPP 5G network, various aspects need to be considered and developed to perfect the 5G technology. Currently, details regarding the MRO mechanism for SPAR or SPCR and SCG fault information procedures have not yet been discussed in the 3GPP 5G technology. Summary of the Invention [Means for solving the problem]

[0005] Some embodiments of the present application provide a method that may be performed by a UE, the method including: receiving configuration information from a master node (MN) regarding a primary cell of a secondary cell group (PSCell) addition or modification procedure, the configuration information including a trigger condition for transmitting assistance information, the assistance information relating to successful completion of the PSCell addition or modification procedure; and transmitting the assistance information to at least one of the MN, a source secondary node (SN), or a target SN in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition.

[0006] In some embodiments, the PSCell addition or change procedure includes at least one of a PSCell addition procedure, a conditional PSCell addition (CPA) procedure, a PSCell change procedure, an MN-initiated conditional PSCell change (CPC) procedure, or an SN-initiated CPC procedure.

[0007] In some embodiments, in response to the configuration information relating to at least one of a PSCell addition procedure, a CPA procedure, or an MN-initiated CPC procedure, a first threshold value associated with a handover timer for the triggering condition is configured by the target SN, or a second threshold value associated with a physical layer problem timer for the triggering condition is configured by the MN, or a third threshold value associated with a timer for initiating failure recovery based on triggering a measurement report for the triggering condition is configured by the MN. In some embodiments, at least one of the aforementioned threshold values ​​is a percentage value of a timer length.

[0008] In some further embodiments, in response to the configuration information relating to an SN-initiated CPC procedure, a fourth threshold associated with a physical layer problem timer for the triggering condition is configured by the source SN, or a fifth threshold associated with a timer for initiating fault recovery based on triggering a measurement report for the triggering condition is configured by the source SN, or a sixth threshold associated with a handover timer for the triggering condition is configured by the target SN, or a seventh threshold associated with a physical layer problem timer for the triggering condition is configured by the MN, or an eighth threshold associated with a timer for initiating fault recovery for the triggering condition is configured by the MN. In some embodiments, at least one of the aforementioned thresholds is a percentage of the timer length.

[0009] In some embodiments, the trigger conditions for transmitting the assistant information include: the elapsed duration of the handover timer exceeding the above-mentioned first threshold multiplied by the length of the handover timer; the elapsed duration of the physical layer problem timer exceeding the above-mentioned second threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeding the above-mentioned third threshold multiplied by the length of the timer for initiating fault recovery; the elapsed duration of the physical layer problem timer exceeding the above-mentioned fourth threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeding the above-mentioned fifth threshold multiplied by the length of the timer for initiating fault recovery. the elapsed duration of the handover timer exceeds the aforementioned sixth threshold multiplied by the length of the handover timer, the elapsed duration of the physical layer problem timer exceeds the aforementioned seventh threshold multiplied by the length of the physical layer problem timer, the elapsed duration of the timer for initiating fault recovery exceeds the aforementioned eighth threshold multiplied by the length of the timer for initiating fault recovery, expiry of the handover timer, expiry of the physical layer problem timer, expiry of the timer for initiating fault recovery, or the elapsed duration of the physical layer problem timer after initiating an SCG fault information procedure exceeds another threshold multiplied by the length of the physical layer problem timer.

[0010] In some embodiments, in response to the source SN configuring that the configuration information includes a trigger condition for transmitting assistant information, the configuration information including the trigger condition is received by the MN from the source SN via an SN Change Requested message. In some other embodiments, in response to the target SN configuring that the configuration information includes a trigger condition for transmitting assistant information, the configuration information including the trigger condition is received by the MN from the target SN via an SN Addition Request Acknowledgement message.

[0011] In some embodiments, the method further comprises, in response to satisfying at least one trigger condition in the configuration information, transmitting information to the MN indicating which trigger condition is satisfied. In one embodiment, the information is carried in an RRC reconfiguration complete message. In one embodiment, the information includes at least one of: information indicating that a trigger condition related to a physical layer problem timer is satisfied for SPAR or SPCR in response to satisfying a trigger condition related to a physical layer problem timer; or information indicating that a trigger condition related to a timer for initiating failure recovery based on triggering a measurement report is satisfied for SPAR or SPCR in response to satisfying a trigger condition related to a timer for initiating failure recovery.

[0012] In some embodiments, the method further comprises receiving a request from the MN, the request including information indicating that the SPAR or SPCR should be reported. In one embodiment, the request may be carried in a UE Information Request message. In some embodiments, the assistant information is sent in a response to the MN, the assistant information including the SPAR or SPCR. In one embodiment, the response is carried in a UE Information Response message.

[0013] In some embodiments, the method further includes transmitting information to the target SN indicating that the SPAR or SPCR is available. In some embodiments, the method further includes receiving a request from the target SN for the SPAR or SPCR, and transmitting the SPAR or SPCR to the target SN in response to receiving the request from the target SN.

[0014] Some embodiments of the present application also provide a UE, the UE including: a processor and a transceiver coupled to the processor, the processor being configured to: receive configuration information related to a PSCell addition or modification procedure from an MN via the transceiver, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; and transmit the assistant information via the transceiver to at least one of the MN, a source SN, or a target SN in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition.

[0015] Some embodiments of the present application provide a method that may be performed by a UE, the method including initiating an SCG failure information procedure and transmitting at least one of "information indicating whether a physical layer problem timer is running" or "information indicating whether a timer for initiating failure recovery based on triggering a measurement report is running" to an MN.

[0016] In some embodiments, the method further includes, in response to the physical layer problem timer being running, transmitting to the MN an elapsed duration of the physical layer problem timer after initiating the SCG fault information procedure, or in response to the timer for initiating fault recovery being running, transmitting to the MN an elapsed duration of the timer for initiating fault recovery after initiating the SCG fault information procedure.

[0017] Some embodiments of the present application also provide a UE, which includes: a processor; and a transceiver coupled to the processor, wherein the processor is configured to initiate an SCG fault information procedure and send an SCG fault information message to the MN via the transceiver, wherein the SCG fault information message includes at least one of "information indicating whether a physical layer problem timer is running" or "information indicating whether a timer for initiating fault recovery based on triggering a measurement report is running."

[0018] Some embodiments of the present application provide a method that may be performed by a network node (e.g., an MN), the method including: transmitting configuration information related to a PSCell addition or modification procedure to a UE, the configuration information including a trigger condition for transmitting assistance information, the assistance information relating to successful completion of the PSCell addition or modification procedure; and receiving the assistance information from the UE in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition.

[0019] In some embodiments, the method further includes receiving configuration information from the source SN or the target SN, the configuration information including the trigger condition, before transmitting the configuration information.

[0020] In some embodiments, the configuration information is received by the MN from the source SN via an SN Change Requested message in response to the configuration information being configured by the source SN. In some other embodiments, the configuration information is received by the MN from the target SN via an SN Addition Request Acknowledgement message in response to the configuration information being configured by the target SN.

[0021] In some embodiments, the PSCell addition or modification procedure includes at least one of a PSCell addition procedure, a CPA procedure, a PSCell modification procedure, an MN-initiated CPC procedure, or an SN-initiated CPC procedure.

[0022] In some embodiments, in response to the configuration information relating to at least one of a PSCell addition procedure, a CPA procedure, or an MN-initiated CPC procedure, a first threshold value associated with a handover timer for the triggering condition is configured by the target SN, or a second threshold value associated with a physical layer problem timer for the triggering condition is configured by the MN, or a third threshold value associated with a timer for initiating failure recovery based on triggering a measurement report for the triggering condition is configured by the MN. In some embodiments, at least one of the aforementioned threshold values ​​is a percentage value of a timer length.

[0023] In some further embodiments, in response to the configuration information relating to an SN-initiated CPC procedure, a fourth threshold associated with a physical layer problem timer for the triggering condition is configured by the source SN, or a fifth threshold associated with a timer for initiating fault recovery based on triggering a measurement report for the triggering condition is configured by the source SN, or a sixth threshold associated with a handover timer for the triggering condition is configured by the target SN, or a seventh threshold associated with a physical layer problem timer for the triggering condition is configured by the MN, or an eighth threshold associated with a timer for initiating fault recovery for the triggering condition is configured by the MN. In some embodiments, at least one of the aforementioned thresholds is a percentage of the timer length.

[0024] In some embodiments, the trigger conditions for transmitting the assistant information include: the elapsed duration of the handover timer exceeding the above-mentioned first threshold multiplied by the length of the handover timer; the elapsed duration of the physical layer problem timer exceeding the above-mentioned second threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeding the above-mentioned third threshold multiplied by the length of the timer for initiating fault recovery; the elapsed duration of the physical layer problem timer exceeding the above-mentioned fourth threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeding the above-mentioned fifth threshold multiplied by the length of the timer for initiating fault recovery. the elapsed duration of the handover timer exceeds the aforementioned sixth threshold multiplied by the length of the handover timer, the elapsed duration of the physical layer problem timer exceeds the aforementioned seventh threshold multiplied by the length of the physical layer problem timer, the elapsed duration of the timer for initiating fault recovery exceeds the aforementioned eighth threshold multiplied by the length of the timer for initiating fault recovery, expiry of the handover timer, expiry of the physical layer problem timer, expiry of the timer for initiating fault recovery, or the elapsed duration of the physical layer problem timer after initiating an SCG fault information procedure exceeds another threshold multiplied by the length of the physical layer problem timer.

[0025] In some embodiments, the method further includes receiving information from the UE indicating which trigger conditions are satisfied in response to satisfying at least one trigger condition in the configuration information, wherein the information includes at least one of: information indicating that a trigger condition related to a physical layer problem timer is satisfied for SPAR or SPCR in response to satisfying a trigger condition related to a physical layer problem timer, or information indicating that a trigger condition related to a timer for initiating fault recovery based on triggering a measurement report is satisfied for SPAR or SPCR in response to satisfying a trigger condition related to a timer for initiating fault recovery.

[0026] In some embodiments, the method further includes forwarding the information to the SN during an SN-initiated PSCell change procedure or an SN-initiated Conditional PSCell Change (CPC) procedure.

[0027] In some embodiments, the method further includes sending a request to the UE, the request including information indicating that the SPAR or SPCR should be reported. In some embodiments, the request is carried in a UE Information Request message. In some embodiments, the assistant information is received in a response from the UE, the assistant information including the SPAR or SPCR. In some embodiments, the response is carried in a UE Information Response message.

[0028] In some embodiments, the method further includes receiving a request from the source SN indicating that the SPAR or SPCR should be reported and forwarding the request to the UE. In some embodiments, the assistant information is received from the UE during an SN-initiated PSCell change procedure or an SN-initiated CPC procedure, the assistant information including the SPAR or SPCR, and the method further includes forwarding the assistant information to the source SN.

[0029] Some embodiments of the present application also provide a network node (e.g., MN), including: a processor and a transceiver coupled to the processor, wherein the processor is configured to: transmit configuration information related to a PSCell addition or modification procedure to a UE via the transceiver, the configuration information including a trigger condition for transmitting assistance information, the assistance information relating to successful completion of the PSCell addition or modification procedure; and receive the assistance information from the UE via the transceiver in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition.

[0030] Some embodiments of the present application provide a method that may be performed by a source network node (e.g., a source SN), the method including: generating configuration information related to a PSCell modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information related to successful completion of the PSCell modification procedure; and transmitting the configuration information to a UE via an MN.

[0031] In some embodiments, the PSCell change procedure includes at least one of a PSCell change procedure or an SN-initiated CPC procedure. In some embodiments, a first threshold associated with a physical layer problem timer for a triggering condition is configured by the source SN, or a second threshold associated with a timer for initiating fault recovery based on triggering a measurement report for the triggering condition is configured by the source SN. In some embodiments, at least one of these two thresholds is a percentage value of the timer length.

[0032] In some embodiments, the trigger conditions for transmitting the assistant information include at least one of the following: the elapsed duration of the physical layer problem timer exceeds the above-mentioned first threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeds the above-mentioned second threshold multiplied by the length of the timer for initiating fault recovery; expiration of the physical layer problem timer; expiration of the timer for initiating fault recovery; or the elapsed duration of the physical layer problem timer after initiating the SCG fault information procedure exceeds another threshold multiplied by the length of the physical layer problem timer.

[0033] In some embodiments, the method further includes receiving assistant information in response to successful completion of the PSCell change procedure and in response to satisfying the trigger condition.

[0034] In some embodiments, configuration information including the trigger condition is sent to the UE and assistant information is received from the UE. In some other embodiments, configuration information including the trigger condition is sent to the MN and assistant information is received from the MN. In response to the configuration information being sent to the MN, the configuration information may be carried in an SN Change Requested message.

[0035] In some embodiments, the method further includes receiving information from the MN, the information indicating that a trigger condition related to the SPCR has been met. In some embodiments, the method further includes sending a request to the MN, the request including information indicating that the SPCR should be reported. The request may be carried in a UE Information Request message. In some embodiments, the Assistant Information is received in a response from the MN, the Assistant Information including the SPCR. The response may be carried in a UE Information Response message.

[0036] Some embodiments of the present application also provide a source network node (e.g., a source SN), which includes: a processor; and a transceiver coupled to the processor, wherein the processor is configured to: generate configuration information related to a PSCell modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell modification procedure; and transmit the configuration information via the transceiver to a UE via an MN.

[0037] Some embodiments of the present application provide a method that may be performed by a target network node (e.g., a target SN). The method includes generating configuration information related to a PSCell addition or modification procedure, the configuration information including a trigger condition for transmitting assistance information, the assistance information related to successful completion of the PSCell addition or modification procedure, and transmitting the configuration information to at least one of a UE or an MN. In some embodiments, the configuration information is carried in an SN addition request acknowledgement message.

[0038] In some embodiments, the PSCell addition or modification procedure includes at least one of a PSCell addition procedure, a CPA procedure, a PSCell modification procedure, an MN-initiated CPC procedure, or an SN-initiated CPC procedure.

[0039] In some embodiments, the trigger condition relates to a threshold value associated with the handover timer. The threshold value may be a percentage value of the timer length. In some embodiments, the trigger condition for transmitting the assistant information includes at least one of the following: the elapsed duration of the handover timer exceeds the threshold value multiplied by the length of the handover timer, or the expiration of the handover timer.

[0040] In some embodiments, the method further includes receiving assistant information from the UE in response to successful completion of the PSCell addition or modification procedure and in response to satisfying a trigger condition.

[0041] In some embodiments, the method further includes receiving information from the UE indicating that a trigger condition related to SPCR or SPAR is met. In some embodiments, the method further includes sending a request to the UE, the request including information indicating that SPCR or SPAR should be reported. The request may be carried in a UE Information Request message. In some embodiments, the assistant information is received in a response from the UE, the assistant information including the SPCR or SPAR. The response may be carried in a UE Information Response message.

[0042] Some embodiments of the present application also provide a target network node (e.g., a target SN), which includes: a processor and a transceiver coupled to the processor, wherein the processor is configured to: generate configuration information related to a PSCell addition or modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; and transmit the configuration information to at least one of a UE or an MN via the transceiver.

[0043] Some embodiments of the present application provide an apparatus, the apparatus including: a non-transitory computer-readable medium having computer-executable instructions stored thereon, receiving circuitry, transmitting circuitry, and a processor coupled to the non-transitory computer-readable medium, the receiving circuitry, and the transmitting circuitry, the computer-executable instructions causing the processor to perform any of the above-described methods performed by a UE or a network node (e.g., an MN, a source SN, or a target SN).

[0044] The details of one or more examples are set forth in the accompanying drawings and description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. Those skilled in the art will be familiar with the use of terms such as "first," "second," and "third," which are used for clarity of description only and should not be construed as any actual limitation, such as, for example, a sequence limitation.

[0045] To explain how the advantages and features of the applications may be obtained, the description of the applications will be expressed by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. These drawings only illustrate exemplary embodiments of the applications and therefore should not be considered as limiting their scope. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a schematic diagram of a wireless communication system according to some embodiments of the present application. [Figure 2] FIG. 1 illustrates an exemplary SCG fault information procedure according to some embodiments of the present application. [Figure 3] FIG. 1 illustrates an example UE information procedure according to some embodiments of the present application. [Figure 4] FIG. 1 illustrates an exemplary fault indication procedure according to some embodiments of the present application. [Figure 5] FIG. 1 illustrates an exemplary access and mobility indication procedure according to some embodiments of the present application. [Figure 6] FIG. 1 is an exemplary block diagram of an apparatus according to some embodiments of the present application. [Figure 7] 10 is a further exemplary flowchart of a PSCell addition and reporting for a conditional PSCell addition procedure according to some embodiments of the present application. [Figure 8] 10 is a further exemplary flowchart of an MN-initiated SN change procedure according to some embodiments of the present application. [Figure 9] 10 is a further exemplary flowchart of an SN-initiated SN change procedure according to some embodiments of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0047] The detailed description of the accompanying drawings is intended as an illustration of a preferred embodiment of the present application and is not intended to represent the only form in which the present application may be practiced. It is to be understood that the same or equivalent functions may be accomplished by various embodiments that are intended to be encompassed within the spirit and scope of the present application.

[0048] Reference will now be made in detail to several embodiments of the present application, examples of which are illustrated in the accompanying drawings. For ease of understanding, embodiments are provided under specific network architectures and new service scenarios, such as Third Generation Partnership Project (3GPP) LTE and LTE Advanced, 3GPP 5G NR, 5G Advanced, 6G, etc. It is contemplated that with the development of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems, and furthermore, the terms described in the present application may change, which shall not affect the principles of the present application.

[0049] FIG. 1 shows a schematic diagram of a wireless communication system according to some embodiments of the present application.

[0050] As shown in Figure 1, the wireless communication system 100 may be a dual connectivity system 100 including at least one UE 101, at least one MN 102, and at least one SN 103. In particular, the dual connectivity system 100 in Figure 1 includes, for purposes of illustration, one UE 101, one MN 102, and one SN 103 shown. Although a particular number of UEs 101, MNs 102, and SNs 103 are shown in Figure 1, it is contemplated that any number of UEs 101, MNs 102, and SNs 103 may be included in the wireless communication system 100.

[0051] 1 , the UE 101 may be connected to the MN 102 and the SN 103 via a network interface, for example, a Uu interface as specified in a 3GPP standard document. The MN 102 and the SN 103 may be connected to each other via a network interface, for example, an Xn interface as specified in a 3GPP standard document. The MN 102 may be connected to a core network via a network interface (not shown in FIG. 1 ). The UE 101 may be configured to utilize resources provided by the MN 102 and the SN 103 to perform data transmission.

[0052] The 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, the 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, the 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, the MN 102 may be a gNB.

[0053] The MN 102 may be associated with an MCG. The MCG may refer to a group of serving cells associated with the MN 102 and may include a primary cell (PCell) of the MCG and optionally one or more SCells. The PCell may provide control plane connectivity to the UE 101.

[0054] The SN 103 may refer to a radio access node that does not have a control plane connection to a core network but provides additional resources to the UE 101. In one embodiment of the present application, in an EN-DC scenario, the SN 103 may be an en-gNB. In another embodiment of the present application, in an NE-DC scenario, the SN 103 may be an ng-eNB. In yet another embodiment of the present application, in an NR-DC scenario or an NGEN-DC scenario, the SN 103 may be a gNB.

[0055] The SN 103 may be associated with an SCG. An SCG may refer to a group of serving cells associated with the SN 103 and may include a Primary Secondary Cell (PSCell) and optionally one or more SCells. The PCell of the MCG and the PSCell of the SCG may also be referred to as special cells (SpCells).

[0056] In some embodiments of the present application, the 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 television (e.g., a television connected to the Internet), a set-top box, a game console, a security system (including security cameras), 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, the UE 101 may include a portable wireless communication device, a smartphone, a cellular telephone, a flip phone, a device with a subscriber identity module, a personal computer, selective call receive circuitry, or any other device capable of sending and receiving communication signals over a wireless network. In some other embodiments of the present application, the UE 101 may include a wearable device such as a smart watch, a fitness band, an optical head-mounted display, etc. Moreover, the UE 101 may be referred to as a subscriber unit, a mobile, 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 may be described using other terms used in the art.

[0057] In general, the purpose of the SCG failure information procedure is to inform the MN about SCG failures experienced by the UE, i.e. SCG radio link failure, SCG reconfiguration failure with synchronization, SCG configuration failure for RRC messages on signaling radio bearer (SRB) 3, and SCG integrity check failure. The UE initiates the SCG failure information procedure to report an SCG failure when neither the MCG nor the SCG transmission is interrupted and when at least one of the following conditions is met: (1) When RLF is detected against SCG, (2) During reconfiguration with SCG synchronization failure, (3) When an SCG configuration failure occurs, or (4) When an integrity check failure is indicated from the SCG lower layer related to SRB3.

[0058] 2 illustrates an exemplary SCG failure information procedure according to some embodiments of the present application. The embodiment of FIG. 2 illustrates a procedure in which a UE (e.g., UE 210) communicates with an MN (e.g., MN 220). In some examples, the UE 210 may function as the UE 101 in FIG. 1. The MN 220 may function as the MN 102 in FIG. 1.

[0059] As shown in Figure 2, in operation 201A, the UE 210 and the MN 220 perform an RRC reconfiguration procedure. Upon initiating the SCG failure information procedure, the UE 210 shall suspend SCG transmission for all SRBs, data radio bearers (DRBs), and backhaul (BH) radio link control (RLC) channels, if any, and shall send an SCGFailureInformation message. In operation 202A as shown in Figure 2, the UE 210 sends the SCGFailureInformation message to the MN 220. The message may include a failureType and a measurement result.

[0060] In general, one of the functions of the MRO mechanism is to detect connectivity failures that occur due to "too early handover", "too late handover", or "handover to the wrong cell". These problems are defined as follows: (1) [Too late handover within the system] RLF occurs after the UE has remained in a cell for a long period of time, and the UE attempts to re-establish a radio link connection in a different cell. (2) [Premature handover within the system] After a successful handover from a source cell to a target cell or a handover failure occurs during the handover procedure, a short RLF occurs and the UE attempts to re-establish a radio link connection within the source cell. (3) [Intra-system handover to incorrect cell] After a successful handover from a source cell to a target cell or a handover failure occurs during the handover procedure, a brief RLF occurs and the UE attempts to re-establish a radio link connection in a cell other than the source and target cells.

[0061] In the above definition, "successful handover" refers to the state of the UE, i.e., the successful completion of the radio access (RA) procedure.

[0062] After an RLF or handover failure occurs, the UE performs a re-establishment procedure within the cell. The UE stores some information related to the RLF failure and / or handover information. The UE stores the latest RLF report, including both LTE and NR RLF reports, until the RLF report is fetched by the network node or for 48 hours after the connection failure is detected. The UE makes the RLF report available to the network node for analysis of the connection failure.

[0063] Generally, the UE information procedure is used by a network node to request a UE to report information. After the network node receives information indicating that RLF information or RA failure information is available, the network node may send a UEInformationRequest message to the UE containing an RLF report request and / or an RA report request. When the UE receives the request from the network node, the UE sends a UEInformationResponse message to the network node containing the RLF report and / or RA report.

[0064] 3 illustrates an exemplary UE information procedure according to some embodiments of the present application. The embodiment of FIG. 3 illustrates a procedure in which a UE (e.g., UE 310) communicates with a BS (e.g., BS 320). In some examples, the UE 310 may function as the UE 101 in FIG. 1. The BS 320 may function as the MN 102 or the SN 103 in FIG. 1.

[0065] 3, in operation 301A, a BS 320 (e.g., the MN 102 as illustrated and shown in FIG. 1) sends a UEInformationRequest message to a UE 310 (e.g., the UE 101 as illustrated and shown in FIG. 1). The BS 320 may be a source BS that controls a serving cell of the UE 310. In operation 302A, the UE 310 sends a UEInformationResponse message including an RLF report to the BS 320. The BS 320 can optimize the mobility issue based on the response sent from the UE 310.

[0066] To extend the MRO functionality in 3GPP 5G NR to provide more robust mobility through reporting failure events observed during a successful handover, a successful handover report (SHR) is introduced. The UE may compile an SHR related to a successful handover, comprising a set of measurements collected during the handover phase, i.e., measurements at the handover trigger, measurements at the end of the handover execution, or measurements after the handover execution. The UE may be configured with a trigger condition for compiling the SHR. Thus, the SHR will only be triggered if the trigger condition is met.

[0067] The availability of the SHR may be indicated by a handover completion message (e.g., an RRCReconfigurationComplete message) sent from the UE to the target NG-RAN node via RRC signaling. The target NG-RAN node may fetch the SHR information via a "UE Information Request Mechanism" or a "UE Information Response Mechanism." Additionally, the target NG-RAN node may then forward the SHR included in the Access and Mobility Indication message shown in FIG. 5 to the source NR-RAN node via the Xn interface to indicate the failures suffered during the successful handover event.

[0068] Upon receiving the SHR, the receiving node may analyze whether its mobility configuration requires adjustment. Such adjustment may result in a change in the mobility configuration, such as a change in the RLM configuration or a change in the mobility threshold between the source and target. Additionally, the target NG-RAN node may further optimize its dedicated RACH beam resources during the handover to be performed based on the beam measurements reported during the successful handover.

[0069] In a 3GPP 5G system, a failure indication procedure may be initiated after a UE attempts to re-establish a radio link connection at NG-RAN node B (e.g., BS 420 in FIG. 4) after a failure at NG-RAN node A (e.g., BS 410 in FIG. 4). NG-RAN node B (e.g., BS 420 in FIG. 4) may initiate the failure indication procedure towards multiple NG-RAN nodes if they control cells that use the physical cell identifier (PCI) signaled by the UE during the RRC re-establishment procedure. The failure indication may also be sent to the node that last served the UE when the NG-RAN node fetches the RLF report from the UE. An example of a failure indication procedure is illustrated in FIG. 4.

[0070] The purpose of the failure indication procedure is to transfer information about an RRC re-establishment attempt or a received RLF report between NG-RAN nodes. The signaling is from the NG-RAN node where the re-establishment attempt is made or where the RLF report is received to the NG-RAN node to which the UE involved was previously connected before the connection failure. This may help in detecting an RLF case or an HO failure case.

[0071] 4 illustrates an exemplary failure indication procedure according to some embodiments of the present application. The embodiment of FIG. 4 illustrates a procedure in which one BS (e.g., BS 410) communicates with another BS (e.g., BS 420). In some examples, the BS 410 may function as an MN (e.g., MN 302 in FIG. 8) or a source SN (e.g., S-SN 303 in FIG. 8), and the BS 420 may function as a target SN (e.g., T-SN 304 in FIG. 8).

[0072] As shown in FIG. 4, in operation 401A, BS 420 transmits a failure indication message to BS 410. BS 410 is a source BS that controls an original serving cell of a UE (e.g., UE 101 as exemplified and illustrated in FIG. 1). BS 420 is a target BS, i.e., a new BS, that controls a target cell or a conditional handover (CHO) candidate cell of the UE. The failure indication message may be transmitted over the Xn interface or the X2 interface. For example, the failure indication message includes an RLF report container. The RLF report container may be transmitted over the Xn interface or the X2 interface.

[0073] In a 3GPP 5G system, an access and mobility indication procedure may be initiated after a successful random access operation of an NG-RAN node. The purpose of the access and mobility indication procedure is to transfer access and mobility related information between NG-RAN nodes over the Xn interface. An example of a failure indication procedure is illustrated in Figure 5.

[0074] 5 illustrates an exemplary access and mobility indication procedure according to some embodiments of the present application. The embodiment of FIG. 5 illustrates a procedure in which one BS (e.g., BS 510) communicates with another BS (e.g., BS 520). In some examples, the BS 510 may function as a target SN (e.g., T-SN 304 in FIG. 8), and the BS 520 may function as a MN (e.g., MN 302 in FIG. 8) or a source SN (e.g., S-SN 303 in FIG. 8).

[0075] As shown in FIG. 5, in operation 501A, BS 510 transmits an access and mobility indication message to BS 520. BS 510 initiates the access and mobility indication procedure by sending the access and mobility indication message to BS 520. The access and mobility indication message may be transmitted over the Xn interface or the X2 interface. For example, the access and mobility indication message includes a container for an RA report list from the UE. The RA report list is defined in 3GPP TS38.331. The RA report container may be transmitted over the Xn interface or the X2 interface.

[0076] Currently, there is no MRO mechanism for a successful PSCell Addition procedure, a Conditional PSCell Addition (CPA) procedure, a Conditional PSCell Change (CPC) procedure, and / or a successful PSCell Change procedure after an SCG Failure Information procedure. For example, the following issues need to be addressed:

[0077] According to the agreement in the 3GPP RAN2#113b meeting based on the contributions, when initiating an SCG fault information procedure, if timer T310 or timer T312 for the PSCell expires before the SCG link is restored, the UE does not trigger another SCG fault information procedure. Therefore, the UE does not stop timer T310 and timer T312 when initiating an SCG fault information procedure. It can be understood that for self-optimization (SON) purposes, whether timer T310 and / or timer T312 are running can be reported to the MCG in the SCG fault information message. Therefore, the problem that needs to be addressed is how to include extended fault information in the SCG fault information message for SCG failure cases.

[0078] Additionally, in cases where the UE sends an SPAR or SPCR, several issues should be addressed: (1) which network node (e.g., MN, source SN, or target SN) configures the trigger conditions for the SPAR or SPCR, (2) which network node (e.g., target SN or MN) the UE should report to, and (3) whether the SPCR should be forwarded to the source SN for SN-initiated and MN-initiated CPC procedures.

[0079] In the legacy SHR, at least one of timers T310, T312, and T304 is configured to trigger the SHR. Similarly, timers T310, T312, and T304 may also be considered as trigger conditions for reporting the SPCR. One use case is that during an SCG failure information procedure, if a trigger condition related to timer T310 or timer T312 is included in the PSCell Change Command, timer T310 or timer T312 may have already expired when the UE receives the PSCell Change Command. Therefore, the problem that needs to be addressed is how to design an MRO mechanism for a successful PSCell Change procedure after receiving a PSCell Change Command during the SCG failure information procedure.

[0080] The embodiments of the present application aim to address the above-mentioned problems. In particular, some embodiments of the present application consider extended failure information included in the SCG failure information message for SCG failure cases. In some embodiments of the present application, when the SCG failure information procedure is triggered and timer T310 or timer T312 is running, the UE does not stop timer T310 or timer T312.

[0081] Some embodiments of the present application introduce trigger conditions for SPAR or SPCR, covering the following cases: PSCell addition procedure, CPA procedure, MN-initiated CPC procedure, SN-initiated CPC procedure, and successful PSCell modification procedure after SCG failure information procedure. The CPA procedure may be considered as a special case of a normal PSCell addition procedure without conditions, and therefore these two procedures may use the same or similar messages to report related information. More details are provided in the following text in combination with the accompanying drawings.

[0082] 6 shows an example block diagram of an apparatus according to some embodiments of the present application. As shown in FIG. 6, the apparatus 600 may include at least one processor 604 and at least one transceiver 602 coupled to the processor 604. The at least one transceiver 602 may be a wired transceiver or a wireless transceiver. The apparatus 600 may be a UE or a network node (e.g., an MN, a source SN, or a target SN).

[0083] In this figure, elements such as at least one transceiver 602 and processor 604 are referred to in the singular, although the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present application, the transceiver 602 may be split into two devices, such as receive circuitry and transmit circuitry. In some embodiments of the present application, the apparatus 600 may further include an input device, a memory, and / or other components.

[0084] In some embodiments of the present application, the apparatus 600 may be a UE (e.g., UE 101, UE 210, UE 201, UE 301, or UE 401 as shown and illustrated in any of FIGS. 1, 2, and 7-9). A processor 604 of the UE may be configured to receive configuration information related to a PSCell addition or modification procedure from an MN (e.g., MN 102 as shown and illustrated in FIG. 1) via the transceiver 602, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure, and to transmit the assistant information to at least one of the MN, the source SN, or the target SN via the transceiver 602 in response to the successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition for transmitting the assistant information. In some embodiments, the assistant information includes at least one of an SHR, an SPAR, or an SPCR.

[0085] According to some embodiments, the PSCell addition or modification procedure includes at least one of a PSCell addition procedure, a CPA procedure, a PSCell modification procedure, an MN-initiated CPC procedure, or an SN-initiated CPC procedure. The processor 604 of the UE applies the configuration information of the PSCell addition procedure upon receiving the configuration information of the PSCell addition procedure. The processor 604 of the UE applies the configuration information of the PSCell modification procedure upon receiving the configuration information of the PSCell modification procedure.

[0086] In some embodiments, in response to the configuration information relating to at least one of a PSCell addition procedure, a CPA procedure, or an MN-initiated CPC procedure, (1) A first threshold associated with a handover timer (e.g., timer T304) for a trigger condition is configured by the target SN; or (2) a second threshold associated with a physical layer problem timer (e.g., timer T310) for a trigger condition is configured by the MN; or (3) A third threshold value associated with the "timer for initiating fault recovery based on triggering a measurement report" (e.g., timer T312) for the trigger condition is configured by the MN. In some embodiments, at least one of the above threshold values ​​is a percentage value of the timer length.

[0087] In some further embodiments, in response to the configuration information relating to an SN-initiated CPC procedure, (1) A fourth threshold associated with a "Physical Layer Problem Timer" (e.g., timer T310) for triggering conditions is configured by the source SN, or (2) A fifth threshold value related to the "timer for initiating fault recovery based on triggering a measurement report" (e.g., timer T312) for the trigger condition is configured by the source SN, or (3) A sixth threshold associated with a handover timer (e.g., timer T304) for a trigger condition is configured by the target SN; or (4) a seventh threshold associated with a physical layer problem timer (e.g., timer T310) for a trigger condition is configured by the MN; or (5) An eighth threshold value related to the "timer for initiating fault recovery" (eg, timer T312) for the trigger condition is configured by the MN.

[0088] In some embodiments, at least one of the first through eighth thresholds mentioned above is a percentage of the timer length, for example, 60%.

[0089] In some embodiments, the trigger condition for sending assistant information includes at least one of the following: (1) The elapsed duration of the handover timer (e.g., timer T304) exceeds a first threshold (e.g., 60%) multiplied by the length of the handover timer (e.g., it is configured as 400 ms). For example, if the elapsed duration of timer T304 is 300 ms, the trigger condition for sending assistant information is deemed to be met because 60%*400 ms=240 ms, and 300 ms is greater than 240 ms. (2) The elapsed duration of the physical layer problem timer (e.g., timer T310) exceeds a second threshold (e.g., 40%) multiplied by the length of the physical layer problem timer (e.g., it is configured as 600 ms). (3) The elapsed duration of the timer for initiating fault recovery (e.g., timer T312) exceeds a third threshold (e.g., 20%) multiplied by the length of the timer for initiating fault recovery (e.g., it is configured as 600 ms). (4) The elapsed duration of the physical layer problem timer (e.g., timer T310) exceeds a fourth threshold (e.g., 40%) multiplied by the length of the physical layer problem timer (e.g., it is configured as 500 ms). (5) The elapsed duration of the timer for initiating fault recovery (e.g., timer T312) exceeds a fifth threshold (e.g., 40%) multiplied by the length of the timer for initiating fault recovery (e.g., it is configured as 400 ms). (6) The elapsed duration of the handover timer (e.g., timer T304) exceeds a sixth threshold (e.g., 40%) multiplied by the length of the handover timer (e.g., it is configured as 300 ms). (7) The elapsed duration of the physical layer problem timer (e.g., timer T310) exceeds a seventh threshold (e.g., 20%) multiplied by the length of the physical layer problem timer (e.g., it is configured as 600 ms). (8) The elapsed duration of the timer for initiating fault recovery (e.g., timer T312) exceeds an eighth threshold (e.g., 60%) multiplied by the length of the timer for initiating fault recovery (e.g., it is configured as 600 ms). (9) Expiration of a handover timer (for example, timer T304). For example, when timer T304 expires, the trigger condition for sending assistant information is considered to be met. (10) Expiration of a physical layer problem timer (for example, timer T310). For example, when timer T310 expires, the trigger condition for sending assistant information is considered to be met. (11) Expiration of a timer (for example, timer T312) for initiating fault recovery. For example, when timer T312 expires, the trigger condition for sending assistant information is considered to be met. (12) The elapsed duration of the physical layer problem timer (e.g., timer T310) after starting the SCG fault information procedure exceeds another threshold (e.g., 60%) multiplied by the length of the physical layer problem timer (e.g., it is configured as 500 ms).

[0090] In some embodiments, in response to the source SN configuring that the configuration information includes a trigger condition for transmitting assistant information, the configuration information including the trigger condition is received by the MN from the source SN via an SN Change Requested message. In some other embodiments, in response to the target SN configuring that the configuration information includes a trigger condition for transmitting assistant information, the configuration information including the trigger condition is received by the MN from the target SN via an SN Addition Request Acknowledgement message.

[0091] In some embodiments, the processor 604 of the UE is configured to, in response to satisfying at least one trigger condition in the configuration information, transmit information indicating which trigger condition has been satisfied to the MN via the transceiver 602. In one embodiment, the information is carried in an RRC reconfiguration complete message. In one embodiment, the information includes at least one of the following: (1) In response to satisfying a trigger condition related to a physical layer problem timer (e.g., timer T310), information indicating that a trigger condition related to a physical layer problem timer (e.g., timer T310) is satisfied for SPAR or SPCR; or (2) In response to satisfying a trigger condition related to a "timer for initiating fault recovery" (e.g., timer T312), information indicating that a trigger condition related to a "timer for initiating fault recovery based on triggering a measurement report" (e.g., timer T312) has been satisfied for SPAR or SPCR.

[0092] In some embodiments, the processor 604 of the UE is configured to receive a request from the MN via the transceiver 602. The request includes information indicating that the SPAR or SPCR should be reported. In some embodiments, the request is carried in a UE Information Request message. In some embodiments, the assistant information is sent in a response to the MN, the assistant information including the SPAR or SPCR. In some embodiments, the response is carried in a UE Information Response message.

[0093] In some embodiments, the processor 604 of the UE is configured to transmit information indicating that the SPAR or SPCR is available to the target SN via the transceiver 602. In some embodiments, the processor 604 of the UE is configured to receive a request for the SPAR or SPCR from the target SN via the transceiver 602, and to transmit the SPAR or SPCR to the target SN via the transceiver 602 in response to receiving the request from the target SN.

[0094] In some embodiments of the present application, the apparatus 600 may be an MN (e.g., an MN 102, an MN 220, a BS 320, an MN 202, an MN 302, or an MN 402 as shown and illustrated in any of FIGS. 1-3 and 7-9). A processor 604 of the MN may be configured to: send configuration information related to a PSCell addition or modification procedure to a UE (e.g., an UE 101 as shown and illustrated in FIG. 1) via the transceiver 602, the configuration information including a trigger condition for sending assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; and receive the assistant information from the UE via the transceiver 602 in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition. In some embodiments, the assistant information includes at least one of an SHR, an SPAR, or an SPCR.

[0095] In some embodiments, the processor 604 of the MN is configured to receive configuration information including the trigger condition from the source SN or the target SN via the transceiver 602 prior to transmitting the configuration information. In one embodiment, in response to the configuration information being configured by the source SN, the configuration information is received by the MN from the source SN via an SN Change Requested message. In one embodiment, in response to the configuration information being configured by the target SN, the configuration information is received by the MN from the target SN via an SN Addition Request Acknowledgement message.

[0096] According to some embodiments, the PSCell addition or modification procedure includes at least one of a PSCell addition procedure, a CPA procedure, a PSCell modification procedure, an MN-initiated CPC procedure, or an SN-initiated CPC procedure. Upon receiving the configuration information of the PSCell addition procedure, the UE applies the configuration information of the PSCell addition procedure. Upon receiving the configuration information of the PSCell modification procedure, the UE applies the configuration information of the PSCell modification procedure.

[0097] According to some embodiments, in response to the configuration information relating to at least one of a PSCell addition procedure, a CPA procedure, or an MN-initiated CPC procedure: (1) A first threshold associated with a handover timer (e.g., timer T304) for a trigger condition is configured by the target SN; or (2) a second threshold associated with a physical layer problem timer (e.g., timer T310) for a trigger condition is configured by the MN; or (3) A third threshold value related to the "timer for initiating fault recovery based on triggering measurement report" (eg, timer T312) for the trigger condition is configured by the MN.

[0098] In some further embodiments, in response to the configuration information relating to an SN-initiated CPC procedure, (1) A fourth threshold associated with a physical layer problem timer (e.g., timer T310) for triggering conditions is configured by the source SN; or (2) a fifth threshold associated with a timer (e.g., timer T312) for initiating fault recovery based on triggering a measurement report for a trigger condition is configured by the source SN; or (3) A sixth threshold associated with a handover timer (e.g., timer T304) for a trigger condition is configured by the target SN; or (4) a seventh threshold associated with a physical layer problem timer (e.g., timer T310) for a trigger condition is configured by the MN; or (5) An eighth threshold associated with a timer (eg, timer T312) for initiating fault recovery for a trigger condition is configured by the MN.

[0099] In some embodiments, at least one of the first through eighth thresholds mentioned above is a percentage of the timer length, for example, 60%.

[0100] In some embodiments, the trigger condition for sending assistant information includes at least one of the following: (1) the elapsed duration of a handover timer (e.g., timer T304) exceeds a first threshold multiplied by the length of the handover timer; (2) the elapsed duration of a physical layer problem timer (e.g., timer T310) exceeds a second threshold multiplied by the length of the physical layer problem timer; (3) the elapsed duration of a timer for initiating fault recovery (e.g., timer T312) exceeds a third threshold multiplied by the length of the timer for initiating fault recovery; (4) the elapsed duration of a physical layer problem timer (e.g., timer T310) exceeds a fourth threshold multiplied by the length of the physical layer problem timer; (5) the elapsed duration of a timer for initiating fault recovery (e.g., timer T312) exceeds a fifth threshold multiplied by the length of the timer for initiating fault recovery; (6) the elapsed duration of a handover timer (e.g., timer T304) exceeds a sixth threshold multiplied by the length of the handover timer; (7) the elapsed duration of a physical layer problem timer (e.g., timer T310) exceeds a seventh threshold multiplied by the length of the physical layer problem timer; (8) the elapsed duration of a timer for initiating fault recovery (e.g., timer T312) exceeds an eighth threshold multiplied by the length of the timer for initiating fault recovery; (9) expiration of a handover timer (e.g., timer T304); (10) Expiration of a physical layer problem timer (e.g., timer T310); (11) Expiration of a timer for initiating fault recovery (e.g., timer T312), or (12) The elapsed duration of the physical layer problem timer (e.g., timer T310) after initiating the SCG fault information procedure exceeds a ninth threshold multiplied by the length of the physical layer problem timer.

[0101] According to some embodiments, the processor 604 of the MN is configured to receive, in response to satisfying at least one trigger condition in the configuration information, information from the UE via the transceiver 602 indicating which trigger condition has been satisfied. In some embodiments, the information includes at least one of the following: (1) In response to satisfying a trigger condition related to a "Physical Layer Problem Timer," information indicating that a trigger condition related to a "Physical Layer Problem Timer" (e.g., timer T310) is satisfied for a SPAR or SPCR; or (2) In response to satisfying a trigger condition related to a "timer for initiating fault recovery" (e.g., timer T312), information indicating that a trigger condition related to a "timer for initiating fault recovery based on triggering a measurement report" (e.g., timer T312) has been satisfied for SPAR or SPCR.

[0102] In some embodiments, the processor 604 of the MN is configured to forward the first information to an SN (e.g., SN 103 as shown and illustrated in FIG. 1) during an SN-initiated PSCell change procedure or an SN-initiated CPC procedure.

[0103] In some embodiments, the processor 604 of the MN is configured to send a request to the UE via the transceiver 602. The request includes information indicating that the SPAR or SPCR should be reported. The request may be carried in a UE Information Request message. In some embodiments, the assistance information is received in a response from the UE, the assistance information including the SPAR or SPCR. The response may be carried in a UE Information Response message.

[0104] According to some embodiments, the processor 604 of the MN is configured to receive a request from the source SN via the transceiver 602 indicating that the SPAR or SPCR should be reported and forward the request to the UE. In some embodiments, the assistant information is received from the UE during an "SN-initiated PSCell change procedure" or an "SN-initiated CPC procedure," and the assistant information includes the SPAR or SPCR. The processor 604 of the MN may be further configured to forward the assistant information to the source SN via the transceiver 602.

[0105] In some embodiments of the present application, the apparatus 600 may be a source SN (e.g., SN 103, BS 410, BS 520, S-SN 303, or S-SN 403 as shown and illustrated in any of FIGS. 1, 4, 5, 8, and 9). The processor 604 of the source SN may be configured to generate configuration information related to a PSCell modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell modification procedure, and transmit the configuration information via an MN (e.g., MN 102 as shown and illustrated in FIG. 1) to a UE (e.g., UE 101 as shown and illustrated in FIG. 1) via the transceiver 602. In some embodiments, the assistant information includes at least one of an SHR, an SPAR, or an SPCR.

[0106] In some embodiments, the PSCell change procedure includes at least one of a PSCell change procedure or an SN-initiated CPC procedure.

[0107] According to some embodiments, a threshold value associated with a physical layer problem timer (e.g., timer T310) for a trigger condition is configured by the source SN. A further threshold value associated with a "timer for initiating fault recovery based on triggering a measurement report" (e.g., timer T312) for a trigger condition is configured by the source SN. The threshold value and / or the further threshold value may be a percentage of the timer length, e.g., 40%.

[0108] In some embodiments, the trigger condition for sending assistant information includes at least one of the following: (1) The elapsed duration of a physical layer problem timer (e.g., timer T310) exceeds a threshold multiplied by the length of the physical layer problem timer; (2) the elapsed duration of a timer for initiating fault recovery (e.g., timer T312) exceeds a further threshold multiplied by the length of the timer for initiating fault recovery; (3) expiration of a physical layer problem timer (e.g., timer T310); (4) expiration of a timer for initiating fault recovery (e.g., timer T312); or (5) The elapsed duration of a physical layer problem timer (e.g., timer T310) after initiating an SCG fault information procedure exceeds another threshold multiplied by the length of the physical layer problem timer.

[0109] In some embodiments, the processor 604 of the source SN is configured to receive assistant information via the transceiver 602 in response to successful completion of the PSCell change procedure and in response to satisfying the trigger condition. In some embodiments, the configuration information including the trigger condition is sent to the UE, and the assistant information is received from the UE. In some other embodiments, the configuration information including the trigger condition is sent to the MN, and the assistant information is received from the MN. In response to the configuration information being sent to the MN, the configuration information may be carried in an SN Change Requested message.

[0110] According to some embodiments, the processor 604 of the source SN is configured to receive information from the MN via the transceiver 602. The information indicates that a trigger condition related to the SPCR has been met. In some embodiments, the processor 604 of the source SN is configured to send a request to the MN. The request includes information indicating that the SPCR should be reported. The request may be carried in a UE Information Request message. In some embodiments, the assistant information is received in a response from the MN, the assistant information including the SPCR. The response may be carried in a UE Information Response message.

[0111] In some embodiments of the present application, the apparatus 600 may be a target SN (e.g., an SN 103, a BS 420, a BS 510, a T-SN 304, or a T-SN 404 as shown and illustrated in any of FIGS. 1, 4, 5, 8, and 9). The processor 604 of the target SN may be configured to generate configuration information related to a primary cell of a secondary cell group (PSCell) addition or modification procedure. The configuration information includes a trigger condition for transmitting assistant information, and the assistant information relates to successful completion of the PSCell addition or modification procedure. The processor 604 of the target SN may be further configured to transmit the configuration information to at least one of a UE (e.g., a UE 101 as shown and illustrated in FIG. 1) or a MN (e.g., a MN 102 as shown and illustrated in FIG. 1) via the transceiver 602. According to some embodiments, the configuration information is carried in an SN addition request acknowledgement message. In some embodiments, the assistant information includes at least one of an SHR, an SPAR, or an SPCR.

[0112] According to some embodiments, the PSCell addition or modification procedure includes at least one of a PSCell addition procedure, a CPA procedure, a PSCell modification procedure, an MN-initiated CPC procedure, or an SN-initiated CPC procedure.

[0113] In some embodiments, the trigger condition relates to a threshold value associated with a handover timer (e.g., timer T304). For example, the threshold value is a percentage value (e.g., 60%) of the timer length. In some embodiments, the trigger condition for transmitting the assistant information includes at least one of the following: the elapsed duration of the handover timer exceeds a threshold value multiplied by the length of the handover timer, or the expiration of the handover timer.

[0114] According to some embodiments, the processor 604 of the target SN is configured to receive assistance information from the UE via the transceiver 602 in response to successful completion of the PSCell addition or modification procedure and in response to satisfying a trigger condition.

[0115] According to some embodiments, the processor 604 of the target SN is configured to receive information from the UE via the transceiver 602 indicating that a trigger condition related to an SPCR or SPAR has been met. In some embodiments, the processor 604 of the target SN is configured to send a request to the UE. The request includes information indicating that the SPCR or SPAR should be reported. The request may be carried in a UE Information Request message. In some embodiments, the assistant information is received in a response from the UE, the assistant information including the SPCR or SPAR. The response may be carried in a UE Information Response message.

[0116] In some embodiments of the present application, the apparatus 600 may be a UE (e.g., UE 101, UE 210, UE 201, UE 301, or UE 401 as illustrated and exemplified in any of FIGS. 1, 2, and 7 to 9). The processor 604 of the UE may be configured to initiate an SCG failure information procedure and send an SCG failure information message to the MN via the transceiver 602, where the SCG failure information message includes at least one of "information indicating whether a physical layer problem timer (e.g., timer T310) is running" or "information indicating whether a timer for initiating failure recovery based on triggering a measurement report (e.g., timer T312) is running." A specific example is described in embodiment 1 for network slicing as follows.

[0117] According to some embodiments, the processor 604 of the UE is configured to, in response to the physical layer problem timer being running, transmit to the MN via the transceiver 602 the elapsed duration of the physical layer problem timer after initiating the SCG fault information procedure, or, in response to the timer for initiating fault recovery (e.g., timer T312) being running, transmit to the MN via the transceiver 602 the elapsed duration of the timer for initiating fault recovery (e.g., timer T312) after initiating the SCG fault information procedure.

[0118] In some embodiments of the present application, the apparatus 600 may include at least one non-transitory computer-readable medium. In some embodiments of the present disclosure, the non-transitory computer-readable medium may have computer-executable instructions stored thereon to cause a processor to perform a method related to a UE or a network node (e.g., an MN, a source SN, or a target SN) as described above. For example, the computer-executable instructions, when executed, cause the processor 604 to interact with the transceiver 602 to perform the operations of the method, e.g., as described in view of FIGS. 7-9.

[0119] The following text describes specific embodiments 1 and 2 of this embodiment as depicted and illustrated in FIG. 6, in which the UE and the network node (eg, MN, source SN, or target SN) perform the following operations:

[0120] Embodiment 1 Embodiment 1 refers to a scenario in which, for an SCG failure case, the extended failure information is included in the SCGFailureInformation message. In detail, in embodiment 1, the following steps may be performed: (1) Step 1: A UE (eg, UE 101 as shown and illustrated in FIG. 1) accesses a network via dual connectivity (DC). - An SN (for example, SN 103 as shown and illustrated in Figure 1) is configured for the UE. (2) Step 2: The UE starts a timer T310 in the SCG. In one embodiment, the UE may start timer T312 in the SCG. (3) Step 3: When at least one of the following conditions is met, the UE initiates an SCG failure information procedure to report an SCG failure: - Upon detection of RLF for SCG, - During reconfiguration with SCG synchronization failure, - When an SCG configuration failure occurs, or - When an integrity check failure is indicated by the SCG lower layer, related to SRB3. (4) Step 4: The UE sends an SCGFailureInformation message. Any or a combination of the following information may be included in the SCGFailureInformation message: 1) FailureType and measurement result. 2) Information about whether timer T310 is running or not may be reported to the MCG in the SCGFailureInformation message. In one embodiment, if timer T310 is running, the elapsed duration of timer T310 when starting the SCG fault information procedure may be reported. 3) Information about whether timer T312 is running or not may be reported to the MCG in the SCGFailureInformation message. In one embodiment, if timer T312 is running, the elapsed duration of timer T312 when starting the SCG fault information procedure may be reported. (5) Step 5: After the MN (eg, MN 102 as shown and illustrated in FIG. 1) receives the SCGFailureInformation message, the MN may send a PSCell change command to the UE, for example, in an RRCReconfiguration message. (6) Step 6: The UE receives an RRCReconfiguration message containing a PSCell change command, and then performs a PSCell change procedure.

[0121] Embodiment 2 Embodiment 2 refers to an MRO mechanism for a successful PSCell change procedure after receiving a PSCell change command during an SCG failure information procedure. In detail, in embodiment 2, the following steps may be performed: (1) Step 1: A UE (for example, UE 301 as shown and illustrated in FIG. 8) accesses a network via a DC. - An SN (for example, S-SN 303 as shown and illustrated in Figure 8) is configured for the UE. (2) Step 2: The UE starts a timer T310 in the SCG. In one embodiment, the UE may start timer T312 in the SCG. (3) Step 3: When at least one of the following conditions is met, the UE initiates an SCG failure information procedure to report an SCG failure: - Upon detection of RLF for SCG, - During reconfiguration with SCG synchronization failure, - When an SCG configuration failure occurs, or - When an integrity check failure is indicated by the SCG lower layer, related to SRB3. (4) Step 4: The UE sends an SCGFailureInformation message. Any or a combination of the following information may be included in the SCGFailureInformation message: 1) FailureType and measurement result. 2) Information about whether timer T310 is running or not may be reported to the MCG in the SCGFailureInformation message. In one embodiment, if timer T310 is running, the elapsed duration of timer T310 when starting the SCG fault information procedure may be reported. 3) Information about whether timer T312 is running or not may be reported to the MCG in the SCGFailureInformation message. In one embodiment, if timer T312 is running, the elapsed duration of timer T312 when starting the SCG fault information procedure may be reported. (5) Step 5: After the MN (e.g., MN 302 as shown and illustrated in FIG. 8) receives the SCGFailureInformation message, the MN may send a PSCell change command to the UE. In some embodiments, the trigger conditions for reporting the SPCR are as follows: - Option 1: The trigger condition associated with timer T310 may be "if the elapsed duration of timer T310 exceeds a configured threshold value". In one embodiment, the configured threshold may be configured as a time value that is less than the time length of timer T310. The expiration of timer T310 may be considered as the trigger condition associated with timer T310 being met. When timer T310 expires, the elapsed duration of timer T310 exceeds the configured threshold (which is less than the time length of timer T310), and therefore the trigger condition is met. Option 2: Expiration of timer T310 may be configured as the triggering condition associated with timer T310 and / or expiry of timer T312 may be configured as the triggering condition associated with timer T312. - Option 3: The elapsed duration of timer T310 after starting the SCG fault information procedure exceeds the configured threshold, i.e. whether the elapsed duration of timer T310 exceeds the configured threshold depends on the time when the SCG fault occurs. In one embodiment, when an SCG fault occurs, an SCG fault information procedure is initiated and the elapsed duration of timer T310 is calculated from the time the SCG fault information procedure was initiated, rather than the start time of timer T310. If the calculated elapsed duration of timer T310 exceeds a configured threshold, the trigger condition is met. The above thresholds for the trigger conditions associated with timer T310 and / or timer T312 may be configured by the MN. - A triggering condition associated with timer T304 may be configured for the UE, and a threshold for the triggering condition associated with timer T304 may be configured by the target SN. (6) Step 6: The UE receives an RRCReconfiguration message containing a PSCell change command, and then performs a PSCell change procedure. (7) Step 7: The UE logs information related to the SPCR if the trigger condition for reporting the SPCR is met. (8) Step 8: The UE sends an RRC message to the target SN (for example, the T-SN 304 as shown and illustrated in FIG. 8). The RRC message includes an indication that the SPCR is available. (9) Step 9: After receiving the indication from the UE, the target SN sends a UEInformationRequest message to the UE. The UEInformationRequest message may include an indication that the SPCR should be reported. (10) Step 10: The UE sends a UEInformationResponse message to the target SN. - The UEInformationResponse message includes the SPCR. (11) Step 11: After the target SN receives the report message from the UE, the target SN sends the SPCR to the MN. The SPCR may be included in an Xn interface message to the MN (eg, a failure indication message or a new Xn interface message). - The reporting message reported by the UE may be sent as a container. - The Xn interface message to the MN includes an indication that the SPCR is available.

[0122] FIG. 7 shows a further exemplary flowchart of a PSCell addition and reporting for a conditional PSCell addition procedure according to some embodiments of the present application.

[0123] The embodiment of Figure 7 aims to address issues in the case where the UE sends an SPAR or SPCR, namely, (1) which network node (e.g., MN, source SN, or target SN) configures the trigger condition for the SPAR or SPCR, (2) which network node (e.g., target SN or MN) the UE should report to, and (3) whether the SPCR should be forwarded to the source SN for SN-initiated and MN-initiated CPC procedures. In particular, the following steps may be performed in the embodiment of Figure 7.

[0124] In operation 211 as shown in FIG. 7, the UE 201 accesses a network node, namely, the MN 202, via a non-DC where the SN is not configured for the UE 201.

[0125] In operation 212 as shown in FIG. 7, MN 202 decides to add one SN to UE 201 and sends an SgNB addition request message or an S-NODE ADDITION REQUEST message to SN 203 (which in some cases may be referred to as target SN 203).

[0126] 7, if the SN 203 can approve the resource request, the SN 203 sends an SgNB addition request acknowledgement message or an S-NODE ADDITION REQUEST ACKNOWLEDGE message to the MN 202. The SN 203 allocates the respective radio resources. (1) In the case of a CPA case, the execution condition for triggering the CPA procedure is included in the message sent in operation 213 . (2) For example, a threshold value for a trigger condition, associated with timer T304, may be included in the message sent in operation 213. The threshold value may be a percentage, for example, 60%. The trigger condition may be that the elapsed duration of a timer (e.g., T304) is greater than the threshold value. For example, if the elapsed duration of timer T304 (e.g., 500 ms) is greater than "60% * the configured length of timer T304," a reporting procedure (e.g., SHR, SPAR, or SPCR) is triggered. That is, the trigger condition for the reporting procedure is met. If the configured length of timer T304 is 600 ms, then "60% * 600 ms" is 360 ms. Because the elapsed duration of timer T304, i.e., 500 ms, is greater than 360 ms, a report is triggered.

[0127] 7, the MN 202 sends an RRCReconfiguration message to the UE 201, including the RRCConfiguration message from the SN 203. For example, a threshold value for a trigger condition, associated with timer T310 or T312 on the SN 203, may be added to the RRCReconfiguration message. The threshold value may be a percentage, for example, 60%.

[0128] In operation 215 as shown in FIG. 7, the UE 201 applies the new configuration and replies to the MN 202 with an RRCReconfigurationComplete message containing an RRC response message, if necessary. (1) In the case of a CPA case, an execution condition for triggering a CPA procedure is included in the message sent in operation 215. When the execution condition for performing the CPA procedure is met, an RRCReconfigurationComplete message is sent.

[0129] In operation 216 as shown in FIG. 7, if an RRC response message is received from UE201, MN202 informs SN203 that UE201 has successfully completed the RRC reconfiguration procedure via an SgNB reconfiguration complete message that includes the encoded RRC response message.

[0130] In operation 217 as shown in Figure 7, the UE 201 performs a random access to the SN 203. After successful random access, the UE 201 sends an indication to indicate that a trigger condition for SPAR, e.g., related to timer T304, is met.

[0131] 7, the MN 202 forwards a message including the indication received from the UE 201 to the SN 203. In some embodiments, after receiving the message including the indication from the MN 202, the SN 203 may send a UEInformationRequest message to the UE 201. The UEInformationRequest message may include an indication to indicate that SPAR should be reported. The UE 201 may then send a UEInformationResponse message to the SN 203. The UEInformationResponse message includes the SPAR.

[0132] Details described in all other embodiments of the present application (e.g., details regarding the MRO mechanism for SPAR or SPCR and SCG fault information procedures) are applicable to the embodiment of Figure 7. Moreover, details described in the embodiment of Figure 7 are applicable to all embodiments of Figures 1-6, 8, and 9. It should be appreciated by those skilled in the art that the sequence of operations in the exemplary procedure in the embodiment of Figure 7 may be changed, and some of the operations in the exemplary procedure in the embodiment of Figure 7 may be removed or modified, without departing from the spirit and scope of the present disclosure.

[0133] Figure 8 shows a further exemplary flowchart of an MN-initiated SN change procedure according to some embodiments of the present application. The embodiment of Figure 8 refers to an MN-initiated CPC procedure. This embodiment of Figure 8 aims to address a problem similar to that addressed by the embodiment of Figure 7 in the case where the UE sends SPAR or SPCR. In particular, the following steps may be performed in the embodiment of Figure 8:

[0134] 8, the UE 301 accesses a network node, that is, the MN 302 and / or the S-SN 303 (which is the source SN), via the DC. The MN 302 and the S-SN 303 are configured for the UE 301.

[0135] In operation 312 as shown in FIG. 8, after MN 302 determines that a PSCell change procedure should be performed based on the measurement results from UE 301, MN 302 sends an SgNB addition request message or an S-NODE ADDITION REQUEST message to T-SN 304 (which is the target SN).

[0136] 8, if the T-SN 304 can approve the resource request, the T-SN 304 sends an SgNB addition request acknowledgement message or an S-NODE ADDITION REQUEST ACKNOWLEDGE message to the MN 302. The T-SN 304 allocates the respective radio resources. (1) In the CPC case, the execution condition for triggering the CPC procedure is included in the message sent in operation 313 . (2) A threshold value for a trigger condition, for example, associated with timer T304, may be added to the message sent in operation 313. The threshold value may be a percentage, for example, 60% or 40%. The trigger condition may be that the elapsed duration of a timer (e.g., T304) is greater than the threshold value. For example, if the elapsed duration of timer T304 (e.g., 600 ms) is greater than "40% * the configured length of timer T304," a reporting procedure (e.g., SHR, SPAR, or SPCR) is triggered. If the configured length of timer T304 is 800 ms, then "40% * 800 ms" is 320 ms. Because 600 ms is greater than 320 ms, the reporting procedure is triggered.

[0137] In operation 314 as shown in Figure 8, if the resource allocation of the T-SN 304 is successful, the MN 302 initiates a resource release procedure of the S-SN 303 via an SgNB release request message. The SgNB release request message may include a cause indicating SCG mobility.

[0138] In operation 315 as shown in FIG. 8, the S-SN 303 sends an SgNB release request acknowledgement message to the MN 302.

[0139] 8, the MN 302 sends an RRCReconfiguration message to the UE 301, including an RRC configuration message from the T-SN 304. A threshold value for a trigger condition, for example, associated with timer T310 or timer T312, may be added in the message sent in operation 316. The threshold value is a percentage, for example, 60%.

[0140] In operation 317 as shown in FIG. 8, the UE 301 applies the new configuration and replies to the MN 302 with an RRCReconfigurationComplete message containing an RRC response message, if necessary. In the case of the CPC case, whether the execution conditions for triggering the CPC procedure are met is included in the message sent in operation 317. If the trigger conditions are met, more information is also included in this message, e.g. the met conditions. When the execution conditions for performing the CPC procedure are met, an RRCReconfigurationComplete message is sent. An indication may be included in the message transmitted in operation 317 to indicate which trigger condition is satisfied if at least one trigger condition is satisfied. For example, if a trigger condition related to timer T310 is satisfied, the indication is included to inform the MN 302. In this case, the MN 302 may transmit a UEInformationRequest message to the UE 301 after receiving the indication from the UE 301. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. Then, the UE 301 transmits a UEInformationResponse to the MN 302. The UEInformationResponse message includes the SPCR. - If the trigger condition for reporting the SPCR is met, the UE 301 may log information for the SPCR.

[0141] In operations 318A and 318B as shown in FIG. 8 , when an RRC response message is received from UE 301, MN 302 informs both S-SN 303 and T-SN 304 that UE 301 has successfully completed the reconfiguration procedure via an SgNB reconfiguration complete message that includes the encoded RRC response message.

[0142] In operation 319 as shown in Figure 8, UE301 performs random access to T-SN304. After successful random access, UE301 sends an indication to indicate that a trigger condition for the SPCR, e.g., associated with T304, is met. Optionally, T-SN304 may send a UEInformationRequest message to UE301 after receiving the indication from UE301. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. UE301 may then send a UEInformationResponse message to T-SN304. The UEInformationResponse message includes the SPCR.

[0143] In operation 321 as shown in FIG. 8, after completing the data transfer from the S-SN 303, the MN 302 sends a UEContextRelease message to the S-SN 303.

[0144] Details described in all other embodiments of the present application (e.g., details regarding the MRO mechanism for SPAR or SPCR and SCG fault information procedures) are applicable to the embodiment of Figure 8. Moreover, details described in the embodiment of Figure 8 are applicable to all embodiments of Figures 1-7 and 9. It should be appreciated by those skilled in the art that the sequence of operations in the exemplary procedure in the embodiment of Figure 8 may be changed, and some of the operations in the exemplary procedure in the embodiment of Figure 8 may be removed or modified, without departing from the spirit and scope of the present disclosure.

[0145] Figure 9 shows a further exemplary flowchart of an SN-initiated SN change procedure according to some embodiments of the present application. The embodiment of Figure 9 refers to an SN-initiated CPC procedure. The embodiment of Figure 9 aims to address a problem similar to that addressed by the embodiments of Figures 7 and 8 in cases where the UE sends an SPAR or SPCR. In particular, the following steps may be performed in the embodiment of Figure 9:

[0146] In operations 411A and 411B as shown in Fig. 9, the UE 401 accesses the network via the DC. The MN 402 and the S-SN 403 (which is the source SN) are configured for the UE 401. In operation 412 as shown in Fig. 9, the S-SN 403 initiates the SN change procedure by sending an SgNB change requested message to the MN 402. (1) In the CPC case, the execution conditions for triggering the CPC procedure for each target cell are included in the message sent in operation 412 . (2) A threshold value for the trigger condition, for example, associated with timer T310 or timer T312, may be added to the message sent in operation 412. The threshold value is a percentage, for example, 60%. If multiple candidate cells are included, the threshold value is for each candidate cell.

[0147] In operation 413 as shown in FIG. 9, after the MN 402 receives the request from the S-SN 403, the MN 402 sends an SgNB addition request message to the T-SN 404.

[0148] 9, if the T-SN 404 can approve the resource request, the T-SN 404 sends an SgNB Addition Request Acknowledgement message to the MN 402. The T-SN 404 allocates the respective radio resources. (1) In the CPC case, the execution condition for triggering the CPC procedure is included in the message sent in operation 414 . (2) For example, a threshold value for the trigger condition, associated with timer T304, may be included in the message sent in operation 414. The threshold value is a percentage, e.g., 60%. If the elapsed time period of timer T304 is greater than "60% * configured length of timer T304" (e.g., 500 ms), a reporting procedure (e.g., SHR, SPAR, or SPCR) is triggered.

[0149] 9, in operation 415, the MN 402 sends an RRCReconfiguration message to the UE 401, including an RRC configuration message from the T-SN 404. A threshold value for a trigger condition, for example, associated with timer T310 or timer T312, may be added in the RRCReconfiguration message. The threshold value may be a percentage of the timer length, for example, 60%.

[0150] In operation 416 as shown in FIG. 9, the UE 401 applies the new configuration and replies to the MN 402 with an RRCConnectionReconfigurationComplete message including an RRCResponse message, if necessary. (1) In the case of the CPC case, the execution condition for triggering the CPC procedure is included in the message sent in operation 416. When the execution condition for performing the CPC procedure is met, the RRCConnectionReconfigurationComplete message is sent. (2) If at least one trigger condition is met, an indication to indicate which trigger condition is met may be added to the message sent in operation 416. For example, if a trigger condition related to timer T310 is met, an indication of that is included to inform the MN 402. (3) In the case where the MN 402 configures the trigger condition, after receiving the indication from the UE 401, the MN 402 sends a UEInformationRequest message to the UE 401. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. Then, the UE 401 may send a UEInformationResponse message to the MN 402. The UEInformationResponse message includes the SPCR. (4) In the case where the S-SN 403 configures the trigger condition, the MN 402 sends an indication from the UE 401 to the S-SN 403. After receiving the indication from the UE 401, the S-SN 403 may send a UEInformationRequest message to the UE 401 via the MN 402. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. The UE 401 may then send a UEInformationResponse message to the S-SN 403 via the MN 402. The UEInformationResponse message includes the SPCR. (5) If the trigger condition for reporting the SPCR is met, the UE 401 may log information for the SPCR.

[0151] In operation 417 as shown in FIG. 9, the MN 402 sends an SgNB change confirmation message to the S-SN 403. (1) In the case where the S-SN 403 configures the trigger condition, the MN 402 sends an indication from the UE 401 (i.e., operation 416) to the S-SN 403. After receiving the indication from the UE 401, the S-SN 403 sends a UEInformationRequest message to the UE 401 via the MN 402. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. The UE 401 may then send a UEInformationResponse message to the S-SN 403 via the MN 402. The UEInformationResponse message includes the SPCR.

[0152] In operation 417A as shown in Figure 9, the UE 401 and the S-SN 403 perform a UE information procedure via the MN 402, for example, as illustrated in the embodiment of Figure 3. In particular, for example, the S-SN 403 may send a UEInformationRequest message to the MN 402. The MN 402 may forward the UEInformationRequest message to the UE 401. The UE 401 may then send a UEInformationResponse message including an RLF report to the MN 402. The MN 402 may forward the UEInformationResponse message including the RLF report to the S-SN 403.

[0153] In operation 418 as shown in FIG. 9, if received from UE 401, MN 402 informs T-SN 404 that UE 401 has successfully completed the RRC reconfiguration procedure via an SgNB reconfiguration complete message containing an encoded RRC response message.

[0154] After operation 418 as shown in FIG. 9, there may be different operations in different embodiments below. (1) In some embodiments, in operation 419 as shown in Fig. 9, the UE 401 performs random access to the T-SN 404. In operation 421 as shown in Fig. 9, after completing data transfer from the S-SN 403, the MN 402 sends a UEContextRelease message to the S-SN 403. (2) In some other embodiments, in operation 419 as shown in FIG. 9 , the UE 401 performs random access to the T-SN 404. After successful random access, the UE 401 transmits an indication to indicate that a trigger condition for the SPCR, e.g., associated with T304, is met. In this case, the T-SN 404 may transmit a UEInformationRequest message to the UE 401 after receiving the indication from the UE 401. The UEInformationRequest message may include an indication to indicate that the SPCR should be reported. The UE 401 may then transmit a UEInformationResponse message to the T-SN 404. The UEInformationResponse message may include the SPCR. The T-SN 404 may forward the reported information to the MN 402. The MN 402 may then forward the received information to the S-SN 403 in an SN-initiated SN change procedure. Next, in operation 421 as shown in FIG. 9, after completing the data transfer from the S-SN 403, the MN 402 sends a UEContextRelease message to the S-SN 403.

[0155] Details described in all other embodiments of the present application (e.g., details regarding the MRO mechanism for SPAR or SPCR and SCG fault information procedures) are applicable to the embodiment of Figure 9. Moreover, details described in the embodiment of Figure 9 are applicable to all embodiments of Figures 1-6 and 8. It should be appreciated by those skilled in the art that the sequence of operations in the exemplary procedure in the embodiment of Figure 9 may be changed, and some of the operations in the exemplary procedure in the embodiment of Figure 9 may be removed or modified, without departing from the spirit and scope of the present disclosure.

[0156] The methods of the present disclosure may be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented in hardware electronic or logic circuits such as general purpose or special purpose computers, programmed microprocessors or microcontrollers and peripheral integrated circuit elements, integrated circuits, discrete component circuits, programmable logic devices, etc. In general, any device having a finite state machine capable of implementing the flowcharts shown in the figures may be used to perform the processing functions of the present disclosure.

[0157] While the present disclosure has been described using specific embodiments thereof, it is apparent that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the present embodiments may be interchanged, added, or substituted among other embodiments. Also, not all elements of each drawing may be required for the operation of the disclosed embodiments. For example, one skilled in the art will be enabled to make and use the teachings of the present disclosure by simply employing the elements of the independent claims. Accordingly, the embodiments of the present disclosure as described herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0158] As used herein, the terms "includes," "including," or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not specifically listed or inherent in such process, method, article, or apparatus. An element preceded by "a," "an," etc., does not, without more constraints, preclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element. Also, the term "another" is defined as at least a second or more. As used herein, the term "having," etc. is defined as "including." [Explanation of symbols]

[0159] 100 Wireless Communication System 101 User Equipment (UE) 102 Master Node (MN) 103 Secondary Node (SN) 201UE 202 MN 203SN 210 UE 220 MN 301UE 302 MN 303 Source SN (S-SN) 304 Target SN (T-SN) 310 UE 320BS 401UE 402 MN 403 S-SN 404 T-SN 410 BS 420 BS 510 BS 520 BS 600 equipment 602 Transceiver 604 processor

Claims

1. A user equipment (UE) for wireless communications, comprising: at least one memory; at least one processor coupled to the at least one memory; The at least one processor: receiving configuration information from a master node (MN) regarding a primary cell of a secondary cell group (PSCell) addition or modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; In response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition, sending the assistant information to at least one of the MN, a source secondary node (SN), or a target SN; and causing the UE to perform the UE.

2. The PSCell addition or modification procedure comprises: PSCell Add Procedure, conditional PSCell addition (CPA) procedure, PSCell change procedure, MN-initiated conditional PSCell change (CPC) procedure, or including at least one of SN-initiated CPC procedures, The UE of claim 1.

3. In response to the configuration information relating to at least one of the PSCell addition procedure, the CPA procedure, or the MN-initiated CPC procedure, a first threshold associated with a handover timer for said trigger condition is configured by said target SN; or a second threshold associated with a physical layer problem timer for said trigger condition is configured by said MN; or a third threshold associated with a timer for initiating fault recovery based on triggering a measurement report for the trigger condition is configured by the MN; The UE of claim 2.

4. In response to the configuration information relating to the SN-initiated CPC procedure, a fourth threshold associated with a physical layer problem timer for said trigger condition is configured by said source SN; or a fifth threshold associated with a timer for initiating fault recovery based on triggering a measurement report for the trigger condition is configured by the source SN; or a sixth threshold associated with a handover timer for said trigger condition is configured by said target SN; or a seventh threshold associated with the physical layer problem timer for the trigger condition is configured by the MN; or an eighth threshold associated with the timer for initiating fault recovery for the trigger condition is configured by the MN; The UE of claim 2.

5. The UE of claim 4, wherein at least one of the fourth threshold, the fifth threshold, the sixth threshold, the seventh threshold, or the eighth threshold is a percentage value of a timer length.

6. The trigger condition is: the elapsed duration of the physical layer problem timer exceeds the fourth threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeds the fifth threshold multiplied by the length of the timer for initiating fault recovery; the elapsed duration of the handover timer exceeds the sixth threshold multiplied by the length of the handover timer; the elapsed duration of the physical layer problem timer exceeds the seventh threshold multiplied by the length of the physical layer problem timer; the elapsed duration of the timer for initiating fault recovery exceeds the eighth threshold multiplied by the length of the timer for initiating fault recovery; expiration of the handover timer; expiration of the physical layer problem timer; Expiration of the timer for initiating fault recovery, or the elapsed duration of the physical layer problem timer after initiating a secondary cell group (SCG) fault information procedure exceeds a ninth threshold multiplied by the length of the physical layer problem timer. The UE of claim 4.

7. In response to the configuration information including the trigger condition for transmitting the assistant information configured by the source SN, the configuration information including the trigger condition is received by the MN from the source SN via an SN change requested message; or In response to the configuration information including the trigger condition for transmitting the assistant information configured by the target SN, the configuration information including the trigger condition is received by the MN from the target SN via an SN addition request acknowledgement message. The UE of claim 1.

8. 10. The UE of claim 1, wherein the at least one processor is further configured to: cause the UE to, in response to satisfying at least one trigger condition in the configuration information, transmit first information to the MN indicating which trigger condition is satisfied.

9. 10. The UE of claim 8, wherein the first information is carried in a radio resource control (RRC) reconfiguration complete message.

10. The first information is in response to satisfying a trigger condition related to a physical layer problem timer, second information indicating that the trigger condition related to the physical layer problem timer is satisfied for a successful PSCell addition report (SPAR) or a successful PSCell change report (SPCR); or and third information indicating that the trigger condition related to a timer for initiating fault recovery based on triggering a measurement report is satisfied for the SPAR or the SPCR in response to satisfying a trigger condition related to the timer for initiating fault recovery. The UE of claim 8.

11. 10. The UE of claim 8, wherein the at least one processor is further configured to cause the UE to receive a request from the MN, the request including information indicating that a successful PSCell addition report (SPAR) or a successful PSCell change report (SPCR) should be reported.

12. The UE according to claim 11, wherein the assistant information is sent in a response to the MN, and the assistant information includes the SPAR or the SPCR.

13. 13. The UE of claim 12, wherein the request is carried in a UE Information Request message and the response is carried in a UE Information Response message.

14. 2. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to transmit information to the target SN indicating that a successful PSCell addition report (SPAR) or a successful PSCell change report (SPCR) is available.

15. the at least one processor: receiving a request for the SPAR or the SPCR from the target SN; and transmitting the SPAR or the SPCR to the target SN in response to receiving the request from the target SN. The UE of claim 14.

16. A processor for wireless communications, comprising: at least one controller coupled to at least one memory, said at least one controller: receiving configuration information from a master node (MN) regarding a primary cell of a secondary cell group (PSCell) addition or modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; In response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition, sending the assistant information to at least one of the MN, a source secondary node (SN), or a target SN; configured to cause the processor to Processor.

17. The at least one controller is further configured to: in response to satisfying at least one trigger condition in the configuration information, cause the processor to transmit first information to the MN indicating which trigger condition has been satisfied.

17. The processor of claim 16.

18. A network node for wireless communications, comprising: at least one memory; at least one processor coupled to the at least one memory; At least one processor transmitting configuration information to a user equipment (UE) regarding a primary cell of a secondary cell group (PSCell) addition or modification procedure, the configuration information including a trigger condition for transmitting assistance information, the assistance information relating to successful completion of the PSCell addition or modification procedure; receiving the assistant information from the UE in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition; configured to cause the network node to Network node.

19. The PSCell addition or modification procedure: PSCell Add Procedure, Conditional PSCell Addition (CPA) procedure, PSCell change procedure, MN-initiated Conditional PSCell Change (CPC) procedure, or including at least one of SN-initiated CPC procedures, 19. A network node according to claim 18.

20. A method performed by a user equipment (UE), comprising: receiving configuration information from a master node (MN) regarding a primary cell of a secondary cell group (PSCell) addition or modification procedure, the configuration information including a trigger condition for transmitting assistant information, the assistant information relating to successful completion of the PSCell addition or modification procedure; and transmitting the assistant information to at least one of the MN, a source secondary node (SN), or a target SN in response to successful completion of the PSCell addition or modification procedure and in response to satisfying the trigger condition. method.

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