Method and apparatus for supporting self-configuration self-optimization

Abstract

The disclosure relates to a 5G or 6G communication system for supporting higher data rates. A method for supporting self-configuration and self-optimization is provided. The method performed by a terminal in a wireless communication system includes receiving, from a source base station, configuration information for a conditional reconfiguration associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell); identifying a failure for an execution associated with the conditional reconfiguration, based on the configuration information; generating failure information based on a cause of the failure, the failure information including first information on whether a condition of the execution is fulfilled and second information on a time that the condition is fulfilled; and transmitting, to a base station that a radio resource control (RRC) connection is established with the terminal, the failure information.

Description

METHOD AND APPARATUS FOR SUPPORTING SELF-CONFIGURATION SELF-OPTIMIZATION

[0001] The present application relates to wireless communication technology, and in particular, to a method and apparatus for supporting self-configuration self-optimization.

[0002]

[0003] In order to meet the increasing demand for wireless data communication services since the deployment of fourth generation (4G) communication systems, efforts have been made to develop an improved fifth generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post LTE System'.

[0004] Fifth generation (5G) mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and may be implemented not only in "Sub 6 GHz" bands such as 3.5 GHz, but also in "Above 6 GHz" bands referred to as millimeter wave (mmWave) including 28 GHz and 39 GHz. In addition, it has been considered to implement sixth generation (6G) mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95 GHz to 3 THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0005] Initially, at the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with an enhanced Mobile BroadBand (eMBB), an Ultra Reliable Low Latency Communications (URLLC), and a massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and a massive Multiple-Input Multiple-Output (MIMO) for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of Bandwidth Part (BWP), new channel coding methods such as a Low Density Parity Check (LDPC) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0006] There are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as a Vehicle-to-everything (V2X) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, New Radio Unlicensed (NR-U) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, a Non-Terrestrial Network (NTN) which is a UE-satellite direct communication system for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0007] Further, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, an Integrated Access and Backhaul (IAB) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and Dual Active Protocol Stack (DAPS) handover, and two-step random access for simplifying random access procedures (2-step random-access channel (RACH) for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on the UE positions.

[0008] As the 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research may be scheduled in connection with eXtended Reality (XR) for efficiently supporting Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0009] Such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and Artificial Intelligence (AI) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of the UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0010] Wireless communication is one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeds 5 billion and continues to grow rapidly. Due to the increasing popularity of smartphones and other mobile data devices (e.g., tablet computers, notebook computers, netbooks, e-book readers, and machine type devices) among consumers and businesses, the demand for wireless data traffic is rapidly growing. To meet the high growth of mobile data traffic and support new applications and deployments, improving wireless interface efficiency and coverage is crucial.

[0011] How to further enhance self-configuration self-optimization is a problem that needs to be solved at present.

[0012]

[0013] The disclosure relates to operations of a user equipment (UE), a base station (BS), and a network in a wireless communication system. More particularly, the disclosure relates to a method and an apparatus for self-configuration and self-optimization.

[0014] Accordingly, an aspect of the disclosure is to provide a method and apparatus for self-configuration and self-optimization associated with a conditional reconfiguration including the conditional handover (CHO) and the conditional PSCell addition / change (CPAC).

[0015] In addition, an aspect of the disclosure is to provide a method and apparatus for identifying the cause and the type of a failure for an execution of the conditional reconfiguration.

[0016] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

[0017] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below.

[0018]

[0019] In accordance with an aspect of the disclosure, a method performed by a terminal in a wireless communication system is provided. The method includes receiving, from a source base station, configuration information for a conditional reconfiguration associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell); identifying a failure for an execution associated with the conditional reconfiguration, based on the configuration information; generating failure information based on a cause of the failure, the failure information including first information on whether a condition of the execution is fulfilled and second information on a time that the condition is fulfilled; and transmitting, to a base station that a radio resource control (RRC) connection is established with the terminal, the failure information.

[0020] In accordance with another aspect of the disclosure, a method performed by a base station in a wireless communication system is provided. The method includes obtaining failure information for a terminal, the failure information including first information on whether a condition of an execution associated with a conditional reconfiguration is fulfilled and second information on a time that the condition is fulfilled, wherein the conditional reconfiguration is associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell); and determining a cause of a failure for the execution for optimization, based on the failure information.

[0021] In accordance with another aspect of the disclosure, a terminal in a wireless communication system is provided. The terminal includes a transceiver; and a processor coupled with the transceiver and configured to receive, from a source base station, configuration information for a conditional reconfiguration associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell), identify a failure for an execution associated with the conditional reconfiguration, based on the configuration information, generate failure information based on a cause of the failure, the failure information including first information on whether a condition of the execution is fulfilled and second information on a time that the condition is fulfilled, and transmit, to a base station that a radio resource control (RRC) connection is established with the terminal, the failure information.

[0022] In accordance with another aspect of the disclosure, a base station in a wireless communication system is provided. The base station includes a transceiver; and a processor coupled with the transceiver and configured to obtain failure information for a terminal, the failure information including first information on whether a condition of an execution associated with a conditional reconfiguration is fulfilled and second information on a time that the condition is fulfilled, wherein the conditional reconfiguration is associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell), and determine a cause of a failure for the execution for optimization, based on the failure information.

[0023] According to an aspect of the present disclosure, there is provided a method performed by a first network node in a communication system, including: establishing or re-establishing a radio resource control, RRC, connection with a user equipment, UE, in which a failure occurs; receiving, from the UE, first information related to the failure, wherein the first information related to the failure comprises one or more of: information related to execution condition of at least one of a conditional handover, CHO, a conditional Primary SCG Cell, PSCell, change, CPC, a Conditional PSCell Addition, CPA, and a Conditional PSCell Addition or Change, CPAC, information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC, identity information of a cell related to at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to reception of configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to the UE transmitting the first information related to the failure to the first network node, information related to a failure of a primary cell, PCell, a Primary SCG Cell, PSCell, or a secondary cell group, SCG.

[0024] According to an embodiment of the present disclosure, the method further comprises transmitting the first information related to the failure obtained from the UE to a second network node, wherein one or more of the first information related to the failure, a cause and / or type of the failure and second information related to the failure are transmitted to a base station causing the failure through the second network node, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE.

[0025] According to an embodiment of the present disclosure, the method further comprises transmitting one or more of a cause and / or type of the failure and second information related to the failure to the base station causing the failure, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE.

[0026] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: a candidate primary SCG cell, PSCell, information list, UE identity information.

[0027] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: a candidate primary SGC cell, PSCell, information list, cell identity information of a suitable PSCell, indication information on being selected among PSCells recommended / provided by a target master base station, UE identity information.

[0028] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: cell identity information of a source cell of a last handover, cell identity information of a failed cell.

[0029] According to an embodiment of the present disclosure, the information related to execution condition of at least one of the CHO, the CPC, the CPA, and the CPAC includes one or more of: information on a CHO execution condition being fulfilled, information on a CHO event for which a execution condition is fulfilled, information on a primary cell for which the CHO execution condition is fulfilled, time information from configuring the CHO to the CHO execution condition being fulfilled, information on a CPC or CPA execution condition being fulfilled, information on an event fulfilling the CPC or CPA execution condition, information on a time fulfilling the CPC or CPA execution condition.

[0030] According to an embodiment of the present disclosure, the information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: indication information on the CHO and CPC, indication information on the CHO and CPA, indication information on the CHO and CPAC.

[0031] According to an embodiment of the present disclosure, the identity information of the cell related to at least one of the CHO, CPC, CPA and CPAC includes one or more of: cell identity information of a failed PSCell, cell identity information of a source PSCell.

[0032] According to an embodiment of the present disclosure, the time information related to reception of the configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: information on time from the UE receiving CHO configuration information or CPC configuration information or CPA configuration information or CHO configuration information including the CPC or CHO configuration information including the CPA to the CPC execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CPA execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CHO execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to a CPAC execution condition being fulfilled, time information from the CHO execution or the CPC execution or the CPA execution or the CPAC execution to the failure.

[0033] According to an embodiment of the present disclosure, the time information related to the UE transmitting the first information related to the failure to the first network node comprises one or more of: time from the failure to the UE transmitting the first information related to the failure to the first network node, time from the CPC execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CPA execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CHO execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node.

[0034] According to an embodiment of the present disclosure, the information related to the failure of the PCell, the PSCell, or the SCG comprises one or more of: information on a execution failure to a candidate target PSCell, information on the execution failure to a candidate target PCell, SCG failure information.

[0035] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of a too early CHO execution, a too early CPC execution, a too early CPA execution, a too early CPAC execution, a too late CHO execution, a too late CPC execution, a too late CPA execution, a too late CPAC execution, a CHO execution to a wrong cell, a CPC execution to a wrong cell, a CPA execution to a wrong cell, a CPAC execution to a wrong cell.

[0036] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of: a too late CHO and CPC execution, a too late CHO and CPA execution, a too late PSCell change, a too late CPC execution, a too late CHO execution and a too early CPC or CPA execution, a too late CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too late CPC or CPA execution, a too early CHO execution and a too early CPC or CPA execution, a CHO execution to a wrong cell and a CPC or CPA execution to a wrong cell, a too early CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too early CPC or CPA execution, a too early CPC or CPA execution.

[0037] According to an embodiment of the present disclosure, the second network node is a master base station last serving the UE.

[0038] According to an embodiment of the present disclosure, the first network node is a master base station last serving the UE.

[0039] According to another aspect of the present disclosure, there is provided a method performed by a second network node in a communication system, comprising: transmitting, to a base station causing the failure, one or more of the first information related to the failure, a cause and / or type of the failure and second information related to the failure, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE, wherein the first information related to the failure comprises one or more of: information related to execution condition of at least one of a conditional handover, CHO, a conditional Primary SCG Cell, PSCell, change, CPC, a Conditional PSCell Addition, CPA, and a Conditional PSCell Addition or Change, CPAC, information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC, identity information of a cell related to at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to reception of configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to the UE transmitting the first information related to the failure to the first network node, information related to a failure of a primary cell, PCell, a Primary SCG Cell, PSCell, or a secondary cell group, SCG.

[0040] According to an embodiment of the present disclosure, the second information related to failure comprises one or more of: a candidate primary SCG cell, PSCell, information list, UE identity information.

[0041] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: a candidate primary SGC cell, PSCell, information list, cell identity information of a suitable PSCell, indication information on being selected among PSCells recommended / provided by a target master base station, UE identity information.

[0042] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: cell identity information of a source cell of a last handover, cell identity information of a failed cell.

[0043] According to an embodiment of the present disclosure, the information related to execution condition of at least one of the CHO, the CPC, the CPA, and the CPAC includes one or more of: information on a CHO execution condition being fulfilled, information on a CHO event for which a execution condition is fulfilled, information on a primary cell for which the CHO execution condition is fulfilled, time information from configuring the CHO to the CHO execution condition being fulfilled, information on a CPC or CPA execution condition being fulfilled, information on an event fulfilling the CPC or CPA execution condition, information on a time fulfilling the CPC or CPA execution condition.

[0044] According to an embodiment of the present disclosure, the information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: indication information on the CHO and CPC, indication information on the CHO and CPA, indication information on the CHO and CPAC.

[0045] According to an embodiment of the present disclosure, the identity information of the cell related to at least one of the CHO, CPC, CPA and CPAC includes one or more of: cell identity information of a failed PSCell, cell identity information of a source PSCell.

[0046] According to an embodiment of the present disclosure, the time information related to reception of the configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: information on time from the UE receiving CHO configuration information or CPC configuration information or CPA configuration information or CHO configuration information including the CPC or CHO configuration information including the CPA to the CPC execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CPA execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CHO execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to a CPAC execution condition being fulfilled, time information from the CHO execution or the CPC execution or the CPA execution or the CPAC execution to the failure.

[0047] According to an embodiment of the present disclosure, the time information related to the UE transmitting the first information related to the failure to the first network node comprises one or more of: time from the failure to the UE transmitting the first information related to the failure to the first network node, time from the CPC execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CPA execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CHO execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node.

[0048] According to an embodiment of the present disclosure, the information related to the failure of the PCell, the PSCell, or the SCG comprises one or more of: information on a execution failure to a candidate target PSCell, information on the execution failure to a candidate target PCell, SCG failure information.

[0049] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of a too early CHO execution, a too early CPC execution, a too early CPA execution, a too early CPAC execution, a too late CHO execution, a too late CPC execution, a too late CPA execution, a too late CPAC execution, a CHO execution to a wrong cell, a CPC execution to a wrong cell, a CPA execution to a wrong cell, a CPAC execution to a wrong cell.

[0050] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of: a too late CHO and CPC execution, a too late CHO and CPA execution, a too late PSCell change, a too late CPC execution, a too late CHO execution and a too early CPC or CPA execution, a too late CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too late CPC or CPA execution, a too early CHO execution and a too early CPC or CPA execution, a CHO execution to a wrong cell and a CPC or CPA execution to a wrong cell, a too early CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too early CPC or CPA execution, a too early CPC or CPA execution.

[0051] According to an embodiment of the present disclosure, the second network node is a master base station last serving the UE.

[0052] According to another aspect of the present disclosure, there is provided a method performed by a User Equipment, UE, in a communication system, comprising: receiving, from a first network node, first information related to a failure; transmitting, to a base station causing the failure, one or more of the first information related to the failure, a cause and / or type of the failure and second information related to the failure, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE, wherein the first information related to the failure comprises one or more of: information related to execution condition of at least one of a conditional handover, CHO, a conditional Primary SCG Cell, PSCell, change, CPC, a Conditional PSCell Addition, CPA, and a Conditional PSCell Addition or Change, CPAC, information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC, identity information of a cell related to at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to reception of configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC, time information related to the UE transmitting the first information related to the failure to the first network node, information related to a failure of a primary cell, PCell, a Primary SCG Cell, PSCell, or a secondary cell group, SCG.

[0053] According to an embodiment of the present disclosure, the method further comprises: the first information related to the failure obtained from the UE is transmitted to a second network node, wherein one or more of the first information related to the failure, a cause and / or type of the failure and second information related to the failure are transmitted to a base station causing the failure through the second network node, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE.

[0054] According to an embodiment of the present disclosure, one or more of a cause and / or type of the failure and second information related to the failure is transmitting to the base station causing the failure through the first network node, wherein the cause and / or type of the failure is determined based on the first information related to the failure obtained from the UE.

[0055] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: a candidate primary SCG cell, PSCell, information list, UE identity information.

[0056] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: a candidate primary SGC cell, PSCell, information list, cell identity information of a suitable PSCell, indication information on being selected among PSCells recommended / provided by a target master base station, UE identity information.

[0057] According to an embodiment of the present disclosure, the second information related to the failure comprises one or more of: cell identity information of a source cell of a last handover, cell identity information of a failed cell.

[0058] According to an embodiment of the present disclosure, the information related to execution condition of at least one of the CHO, the CPC, the CPA, and the CPAC includes one or more of: information on a CHO execution condition being fulfilled, information on a CHO event for which a execution condition is fulfilled, information on a primary cell for which the CHO execution condition is fulfilled, time information from configuring the CHO to the CHO execution condition being fulfilled, information on a CPC or CPA execution condition being fulfilled, information on an event fulfilling the CPC or CPA execution condition, information on a time fulfilling the CPC or CPA execution condition.

[0059] According to an embodiment of the present disclosure, the information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: indication information on the CHO and CPC, indication information on the CHO and CPA, indication information on the CHO and CPAC.

[0060] According to an embodiment of the present disclosure, the identity information of the cell related to at least one of the CHO, CPC, CPA and CPAC includes one or more of: cell identity information of a failed PSCell, cell identity information of a source PSCell.

[0061] According to an embodiment of the present disclosure, the time information related to reception of the configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC comprises one or more of: information on time from the UE receiving CHO configuration information or CPC configuration information or CPA configuration information or CHO configuration information including the CPC or CHO configuration information including the CPA to the CPC execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CPA execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to the CHO execution condition being fulfilled, information on time from the UE receiving the CHO configuration information or the CPC configuration information or the CPA configuration information or the CHO configuration information including the CPC or the CHO configuration information including the CPA to a CPAC execution condition being fulfilled, time information from the CHO execution or the CPC execution or the CPA execution or the CPAC execution to the failure.

[0062] According to an embodiment of the present disclosure, the time information related to the UE transmitting the first information related to the failure to the first network node comprises one or more of: time from the failure to the UE transmitting the first information related to the failure to the first network node, time from the CPC execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CPA execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node, time from the CHO execution condition being fulfilled to the UE transmitting the first information related to the failure to the first network node.

[0063] According to an embodiment of the present disclosure, the information related to the failure of the PCell, the PSCell, or the SCG comprises one or more of: information on a execution failure to a candidate target PSCell, information on the execution failure to a candidate target PCell, SCG failure information.

[0064] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of a too early CHO execution, a too early CPC execution, a too early CPA execution, a too early CPAC execution, a too late CHO execution, a too late CPC execution, a too late CPA execution, a too late CPAC execution, a CHO execution to a wrong cell, a CPC execution to a wrong cell, a CPA execution to a wrong cell, a CPAC execution to a wrong cell.

[0065] According to an embodiment of the present disclosure, the cause and / or type of the failure comprises one or more of: a too late CHO and CPC execution, a too late CHO and CPA execution, a too late PSCell change, a too late CPC execution, a too late CHO execution and a too early CPC or CPA execution, a too late CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too late CPC or CPA execution, a too early CHO execution and a too early CPC or CPA execution, a CHO execution to a wrong cell and a CPC or CPA execution to a wrong cell, a too early CHO execution and a CPC or CPA execution to a wrong cell, a CHO execution to a wrong cell and a too early CPC or CPA execution, a too early CPC or CPA execution.

[0066] According to an embodiment of the present disclosure, the second network node is a master base station last serving the UE.

[0067] According to an embodiment of the present disclosure, the first network node is a master base station last serving the UE.

[0068] In accordance with another aspect of the present disclosure, there is provided a first network node in a communication system, comprising: a transceiver configured to receive and transmit signals; and a processor coupled with the transceiver, and configured to control the first network node to perform the method according to an embodiment of the present disclosure.

[0069] In accordance with another aspect of the present disclosure, there is provided a second network node in a communication system, comprising: a transceiver configured to receive and transmit signals; and a processor coupled with the transceiver, and configured to control the second network node to perform the method according to an embodiment of the present disclosure.

[0070] In accordance with another aspect of the present disclosure, there is provided a user equipment, UE, in a communication system, including: a transceiver configured to receive and transmit signals; and a processor coupled with the transceiver, and configured to control the UE to perform the method according to an embodiment of the present disclosure.

[0071]

[0072] In accordance with an embodiment in the disclosure, the network entity and the terminal may make reasonable optimization, reduce occurrence of subsequent failure, guarantee a service continuity, and reduce a labor cost of an operator, by performing self-configuration and self-optimization.

[0073] The effects obtainable in the disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood from the following description by those skilled in the art to which the disclosure belongs.

[0074]

[0075] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0076] Figure 1 illustrates an exemplary system architecture of system architecture evolution (SAE);

[0077] Figure 2 illustrates a schematic diagrams of an initial overall architecture of 5G;

[0078] Figure 3 illustrates an exemplary flowchart of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0079] Figure 4 illustrates an embodiment of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0080] Figure 5 illustrates an embodiment of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0081] Figure 6 illustrates an embodiment of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0082] Figure 7 illustrates an embodiment of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0083] Figure 8 illustrates an embodiment of a method for supporting self-configuration self-optimization in accordance with the disclosure;

[0084] Figure 9 is a block diagram illustrating an exemplary structure of a network node according to an embodiment of the disclosure;

[0085] Figure 10 is a block diagram illustrating an exemplary structure of a user equipment UE according to an embodiment of the disclosure.

[0086]

[0087] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0088] In order to make the objects, technical solutions and advantages of the embodiments of the disclosure clearer, the technical solutions of the embodiments of the disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the disclosure. Apparently, the described embodiments are part of, but not all of, the embodiments of the disclosure. Based on the described embodiments of the disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of protection of the disclosure.

[0089] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

[0090] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0091] Before undertaking the description of the Detailed Description below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," as well as derivatives thereof, encompass both direct and indirect communication. The terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and / or. The phrase "associated with," as well as derivatives thereof, means to include, be included within, connect to, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" means any device, system or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or in a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. For example, "at least one of: A, B, or C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0092] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as Read-Only Memory (ROM), Random Access Memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A "non-transitory" computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0093] The terminology used herein to describe embodiments of the application is not intended to limit and / or define the scope of the application. For example, unless otherwise defined, technical or scientific terms used in the disclosure shall have their ordinary meanings as understood by those of ordinary skill in the art to which this application belongs.

[0094] It should be understood that the terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but are merely used to distinguish one component from another. The singular forms "a," "an," "the," and the like do not denote a limitation of quantity, but rather denote the presence of at least one, unless the context clearly dictates otherwise.

[0095] As used herein any reference to "one example" or "an example," "one embodiment," or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrases "in one embodiment" or "in an example" in various places in the specification are not necessarily all referring to the same embodiment.

[0096] As used herein, "a portion of" something means "at least some of the thing" and thus may mean less than all of the thing or all of the thing. Thus, "a portion of" a thing includes the entire thing as a special case, i.e., the entire thing is an example of a portion of the thing.

[0097] It will be further understood that the terms "comprises" or "comprising" and similar words mean that the elements or items preceding the word encompass the elements or items listed after the word and their equivalents, but do not exclude other elements or items. The terms "connect" or "connecting" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", and the like are merely used to indicate a relative positional relationship, which may change accordingly when the absolute position of the described object changes.

[0098] The various embodiments used to describe the principles of the disclosure in this patent document, discussed below, are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the disclosure may be implemented in any suitably arranged wireless communication system. For example, although the following detailed description of the embodiments of the disclosure will be directed to LTE and 5G communication systems, those skilled in the art may understand that the main point of the disclosure may also be applied to other communication systems having similar technical backgrounds and channel formats with slight modifications without substantially departing from the scope of the disclosure. The technical solution of the embodiments of the present application may be applied to various communication systems.

[0099] For example, the communication system may include a global system for mobile communications (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) system, a general packet radio service (GPRS), a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD), a universal mobile telecommunication system (UMTS), a worldwide interoperability for microwave access (WiMAX) communication system, a 5th generation (5G) system, a new radio (NR), or the like. Further, the technical solutions of the embodiments of this application may be applied to future-oriented communication technologies. Further, the technical solutions of the embodiments of this application may be applied to future-oriented communication technologies.

[0100] For example, the base station may be at least one of a gNode B, an eNode B (eNB), a Node B, a radio access unit, a base station controller, and a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a mobile phone, a smart phone, a computer or multimedia system capable of performing communication functions. In some embodiments of the disclosure, the downlink (DL) is a wireless transmission path through which signals are transmitted from a base station to a terminal, and the uplink (UL) is a wireless transmission path through which signals are transmitted from a terminal to a base station.

[0101] Accordingly, the various embodiments discussed below for describing the principles of the disclosure herein are for illustration purposes only and should not be interpreted as limiting the scope of the disclosure in any way. Those skilled in the art will understand that the principles of the disclosure may be implemented in any suitably arranged wireless communication system. Although the following detailed description of the embodiments of the disclosure will be directed to 5G, those skilled in the art can understand that the main points of the disclosure may also be applied to other communication systems (for example, beyond 5G (B5G) or 6G) with similar technical backgrounds and channel formats with slight modifications without departing from the scope of the disclosure.

[0102] Hereinafter, the embodiments of the disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the same reference numerals in different drawings will be used to refer to the same elements already described.

[0103] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. This description includes various specific details to assist in that understanding but is to be regarded as exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0104] The terms and phrases used in the following description and claims are not limited to their dictionary meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

[0105] It is to be understood that the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0106] The term "include" or "may include" refers to the existence of the corresponding disclosed functions, operations, or components that may be used in various embodiments of the disclosure, and is not limited to the existence of one or more additional functions, operations, or features. Further, the term "include" or "have" may be interpreted to denote certain characteristics, numbers, steps, operations, constituent elements, components, or a combination thereof, but should not be interpreted to exclude the possibility of existence of one or more other characteristics, numbers, steps, operations, constituent elements, components, or a combination thereof.

[0107] The term "or" as used in various embodiments of the disclosure includes any and all combinations of the listed terms. For example, "A or B" may include A, may include B, or may include both A and B.

[0108] Unless defined differently, all terms (including technical terms or scientific terms) used in the disclosure have the same meanings understood by those skilled in the art to which the disclosure belongs. Generally terms as defined in a dictionary are interpreted to have a meaning consistent with a context in the relevant technical field, and should not be interpreted ideally or excessively formally unless clearly defined as such in the disclosure.

[0109] Figures discussed below, and the various embodiments used to describe the principles of the disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the disclosure may be implemented in any suitably arranged system or device.

[0110]

[0111] Figure 1 illustrates a system architecture 100 of system architecture evolution (SAE).

[0112] User equipment (UE) 101 is a terminal device used to receive data. The evolved universal terrestrial radio access network (E-UTRAN) 102 is a radio access network that includes a macro base station (eNodeB / NodeB) that provides an access radio network interface for UEs. The Mobility Management Entity (MME) 103 is responsible for managing the mobility context, session context and security information of the UE. The serving gateway (SGW) 104 primarily provides the functionality of the user plane, the MME 103 and SGW 104 may be at the same physical entity. The packet data network gateway (PGW) 105 is responsible for charging, lawful interception, etc. functions and may also be in the same physical entity as the SGW 104. The policy and charging rules function entity (PCRF) 106 provides quality of service (QoS) policies and charging criteria. The general packet radio service support node (SGSN) 108 is a network node device in the universal mobile telecommunications system (UMTS) that provides a route for the transmission of data. The home subscriber server (HSS) 109 is the home home subsystem of the UE and is responsible for protecting user information including the current location of the user equipment, the address of the serving node, user security information, packet data context of the user equipment, etc.

[0113]

[0114] Figure 2 illustrates a schematic diagrams of an initial overall architecture of 5G

[0115] Other embodiments of the system architecture 200 could be used without departing from the scope of the disclosure.

[0116] The user equipment (UE) 201 is a terminal device to receive data. The next generation radio access network (NG-RAN) 202 is a radio access network that includes a base station (gNB or eNB connected to the 5G core network 5GC, eNB connected to 5GC also called ng-gNB) that provides an access wireless network interface for a UE. The access control and mobility management function (AMF) 203 is responsible for managing the mobility context of the UE, and security information. The user plane functional entity (UPF) 204 mainly provides the functions of the user plane. The session management function (SMF) 205 is responsible for session management. The data network (DN) 206 contains services such as operators, access to the Internet, and traffic for third parties, among others.

[0117] The exemplary embodiments of the disclosure are further described below in conjunction with the accompanying drawings.

[0118] The text and figures are provided by way of example only to assist in understanding the disclosure. They are not to be construed as limiting the scope of the disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those of skill in the art, based upon the disclosure herein, that changes can be made to the embodiments and examples shown without departing from the scope of the disclosure.

[0119] In order to improve the reliability of change of a primary secondary cell group (SCG) cell (PSCell, SpCell (a primary cell of a master or secondary cell group) of a secondary cell group), a conditional PSCell change (CPC) is defined in the current technology. The CPC in the current technology is internal to a secondary node (SN). Furthermore, in the current technology, a conditional PSCell addition (CPA) and an inter-SN CPC procedure are further defined.

[0120] As understood by those skilled in the art, a "timer" as described in this disclosure may also be referred to as a timer or a time, and these terms are used interchangeably in this disclosure.

[0121] Note that herein, unless explicitly stated to the contrary, "base station" and "node" are used interchangeably, e.g., a master node may also be referred to as a master base station, a secondary node may also be referred to as a secondary base station, a source node may also be referred to as a source base station, a target node may also be referred to as a target base station, a candidate node may also be referred to as a candidate base station, other nodes may also be referred to as other base station, and so on, to name a few. The other base station or node may also be a central unit (CU) in the base station and may also be a central unit control plane (CU-CP) in the base station. The nodes may also be other functional entities in a radio access network (RAN), to which the disclosure is not limited.

[0122] The exemplary embodiments of the disclosure are further described below in conjunction with the accompanying drawings.

[0123] The text and figures are provided by way of example only to assist in understanding the disclosure. They are not to be construed as limiting the scope of the disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those of skill in the art, based upon the disclosure herein, that changes can be made to the embodiments and examples shown without departing from the scope of the disclosure.

[0124]

[0125] Figure 3 illustrates an example flowchart of a method for supporting self-configuration and self-optimization in the disclosure. The method comprises the steps of:

[0126] At step 301, the UE fails. The failure may be one or more of a radio link failure, a handover failure, an SCG failure, and may be other failures. The UE saves information on the failure.

[0127] According to an embodiment of the disclosure, the information on the failure saved by the UE may include at least one of: information related to execution condition of at least one of a conditional handover CHO, a conditional PSCell change CPC, a Conditional PSCell Addition CPA, and a Conditional PSCell Addition or Change CPAC; information related to execution of at least one of the CHO, the CPC, the CPA, and the CPAC; identity / ID information of a cell related to at least one of the CHO, the CPC, the CPA, and the CPAC; time information related to reception of configuration information of at least one of the CHO, the CPC, the CPA, and the CPAC and / or execution of at least one of the CHO, the CPC, the CPA, and the CPAC; information related to the UE; information related to failure of a primary cell PCell, a PSCell, and / or a secondary cell group, SCG; location and / or measurement information of the UE.

[0128] For example, the information on the failure save / maintained by the UE may include one or more of the following:

[0129] - information on a conditional handover (CHO) execution condition being fulfilled, which may be an indication of conditional handover execution condition being fulfilled or other information;

[0130] - information on a conditional handover event for which a execution condition is fulfilled;

[0131] - information on a primary cell for which the conditional handover execution condition is fulfilled, the information on the primary cell including a cell identity / ID, frequency information, and / or a tracking area identity;

[0132] - information on one or more candidate PSCells associated with the primary cell for which the conditional handover execution condition is fulfilled, and the information on the PSCells includes a cell identity, frequency information, and / or a tracking area identity;

[0133] - time information from configuring the conditional handover to the conditional handover execution condition being fulfilled. The conditional handover may also be a conditional handover under a dual connectivity or a conditional handover with a secondary cell group (SCG) (CHO with SCG) or a conditional handover with a candidate SCG (CHO with candidate SCG);

[0134] - time duration for which the conditional handover execution conditions are fulfilled or time from the conditional handover execution conditions being fulfilled to the conditional handover execution conditions being not fulfilled;

[0135] - time information from configuring conditional handover to CPAC execution conditions being fulfilled. The conditional handover can also be a conditional handover under a dual connectivity or a conditional handover with a secondary cell group (SCG) (CHO with SCG) or a conditional handover with candidate SCG (CHO with candidate SCG);

[0136] - time duration for which CPAC execution conditions are fulfilled or time from the CPAC execution conditions being fulfilled to the CPAC execution conditions being not fulfilled;

[0137] - information on a conditional primary SCG cell (PSCell) change (CPC) or a conditional PSCell addition (CPA) execution condition being fulfilled, which may be an indication of CPC or CPA execution condition being fulfilled or other information;

[0138] - information on an event fulfilling the CPC or CPA execution condition;

[0139] - information on an event or a type of a first execution condition(s) being fulfilled, for example, the first execution condition(s) being fulfilled may be the CHO execution condition(s) being fulfilled or the CPAC execution condition(s) being fulfilled, the CHO execution condition(s) being fulfilled means that all events of the CHO execution condition(s) being met, and the CPAC execution condition(s) being fulfilled means that all events of the CPAC execution condition(s) being met;

[0140] - time duration between two execution conditions being fulfilled, for example, time duration between the CHO execution condition being fulfilled and the associated CPAC execution condition being fulfilled, time duration between the CHO execution condition being fulfilled and the associated CPAC execution condition being fulfilled means a time gap between the last CHO execution condition being fulfilled and the last associated CPAC execution condition being fulfilled;

[0141] - indication information that the CHO execution conditions are fulfilled and the CPC or CPA conditions are fulfilled but they are not fulfilled simultaneously;

[0142] - information on an event of which an execution condition is fulfilled, time from configuring a CHO with candidate SCG(s) to fulfilling an execution condition, time from configuring CHO with candidate SCG(s) to a failure, and / or time from fulfilling an execution condition to a failure. If multiple execution conditions are fulfilled (for example, one or more CHO execution conditions and / or one or more CPAC execution conditions are fulfilled), then the above information for each execution condition which is fulfilled are included, multiple execution conditions being fulfilled may be included in the time order of the execution conditions being fulfilled;

[0143] - information on time from a UE receiving conditional handover configuration information or CPC configuration information or CPA configuration information or conditional handover configuration information including the CPC or conditional handover configuration information including the CPA to the CPC execution condition being fulfilled;

[0144] - information on time from the UE receiving the conditional handover configuration information or CPC configuration information or CPA configuration information or conditional handover configuration information including the CPC or conditional handover configuration information including the CPA to the CPA execution condition being fulfilled;

[0145] - information on time from the UE receiving the conditional handover configuration information or the configuration information or the CPA configuration information or the conditional handover configuration information including the CPC or the conditional handover configuration information including the CPA to the CHO execution condition being fulfilled;

[0146] - information on time from the UE receiving the conditional handover configuration information or the CPC configuration information or the CPA configuration information or the conditional handover configuration information including the CPC or the conditional handover configuration information including the CPA to a CPAC execution condition being fulfilled;

[0147] - cell identity information of the PSCell that fulfils the CPC or CPA execution condition;

[0148] - cell identity information on a PCell associated with a PSCell that fulfils the CPC or CPA execution conditions, and the associated PCell is a candidate target PCell;

[0149] - indication information on the CHO and CPC, the CHO and CPC indicating that the CPA is also configured when the CHO is configured or that the CPA may also be executed when the CHO is executed, the indication information indicating that configuration information of the CHO and the CPA is received by the UE or configuration information of the CHO with candidate SCG(s) is received by the UE;

[0150] - indication information on the CHO and CPA, the CHO and CPA indicating that the CPA is also configured when the CHO is configured or that the CPA may also be executed when the CHO is executed, the indication information indicating that configuration information of the CHO and the CPA is received by the UE or configuration information of the CHO with candidate SCG(s) is received by the UE;

[0151] - indication information on the CHO and CPAC, the CHO and CPAC indicating that the CPAC is also configured when the CHO is configured or that the CPAC can also be executed when the CHO is executed, the indication information indicating that the UE receives configuration information on the CHO and the CPAC or that the UE receives configuration information of the CHO with candidate SCG(s);

[0152] - information on candidate PCell(s), which includes a cell identity, execution condition(s), and / or information on whether the execution condition(s) are fulfilled;

[0153] - for each candidate PCell, information on the corresponding candidate PSCell, which includes a cell identity, execution condition(s), and / or information on whether the execution condition(s) are fulfilled;

[0154] - for a candidate PCell, indication information on whether configuration of a candidate PSCell is present;

[0155] - for a candidate PCell, whether an SCG configuration information is present;

[0156] - for a candidate PCell, whether it is CHO only configuration;

[0157] - indication information on CHO only;

[0158] - indication information on CHO with candidate SCG(s), which may indicate that the UE is configured with CHO with candidate SCG(s);

[0159] - indication information on CHO with candidate SCG(s) and CHO only being present, which means that the UE is configured with CHO with candidate SCG(s) and with CHO only;

[0160] - indication information on CHO with candidate SCG(s) and CHO with SCG (CHO with SCG configuration) being present, which means that the UE is configured with CHO with candidate SCG(s) and CHO with SCG;

[0161] - indication information on CHO with candidate SCG(s), CHO only, and CHO with SCG being present, which means that the UE is configured with CHO with candidate SCG(s) and CHO only and CHO with SCG;

[0162] - for a candidate PCell, configuration information on an associated candidate PSCell. The configuration information on the associated candidate PSCell may be configuration information on one or more candidate PSCells. The configuration information on the associated candidate PSCell comprises a PSCell identity, an execution condition for the candidate PSCell;

[0163] - for a candidate PCell, configuration information on an SCG;

[0164] - cell identity information of the failed PSCell;

[0165] - cell identity information of the source PSCell;

[0166] - cell identity information on the source PCell;

[0167] - a C-RNTI of the UE in the source PCell;

[0168] - a C-RNTI of the UE in the source PSCell;

[0169] - identity information on a cell with which the UE attempts to re-establish the radio link connection;

[0170] - cell identity information on a cell to which the UE successfully reconnects;

[0171] - cell identity information on a cell to which the UE attempts to reconnect;

[0172] - identity information on a cell with which a first radio resource control connection re-establishment is attempted after a failure;

[0173] - cell identity information on a cell with which the UE attempts a CHO recovery;

[0174] - cell identity information on a cell on which the CHO is recovered;

[0175] - time from receiving CHO with candidate SCG(s) configuration by the UE, which is the time from the CHO with candidate SCG(s) configuration being received by the UE to RLF Report being sent to the base station or the time from CHO with candidate SCG(s) configuration being received by the UE to a request for the RLF Report being received by the UE from the base station;

[0176] - time from the UE receiving CHO with candidate SCG(s) configuration to the UE sending SCG failure information to the base station, or time from the UE receiving CHO with candidate SCG(s) configuration to the UE receiving a request for the SCG failure information from the base station;

[0177] - location information of the UE;

[0178] - information of a measurement result of the UE, comprising the measurement result on a serving cell and neighboring cell(s) by the UE, and / or the measurement result on a serving PSCell and neighboring cell(s) by the UE;

[0179] - time information from the CHO execution or the CPC execution or the CPA execution or the CPAC execution to the failure;

[0180] - information on a execution failure to a candidate target PSCell;

[0181] - information on the execution failure to a candidate target PCell;

[0182] - SCG failure information. The SCG failure information may be included in a Radio Link Failure Report (RLF Report);

[0183] - time information from the CHO execution to the failure;

[0184] - time information from the CPC execution to the failure;

[0185] - time information from the CPA execution to the failure;

[0186] - time information from the CPAC execution to the failure;

[0187] - indication information that no CHO execution conditions and CPAC execution conditions are fulfilled simultaneously;

[0188] - time information from the CHO execution conditions being fulfilled to the failure, which may be a time from the first CHO execution condition being fulfilled to the failure and / or a time from one or more subsequent execution conditions being fulfilled to the failure;

[0189] - time information from CPAC execution conditions being fulfilled to the failure, which may be a time from the first CPAC execution condition being fulfilled to the failure and / or a time from one or more subsequent execution conditions being fulfilled to the failure;

[0190] - information on candidate PCell(s), which includes a cell identity of the PCell and one or more CHO execution condition(s);

[0191] - information on candidate PSCell(s) corresponding to the candidate PCell, which comprises a PSCell identity and one or more CPC or CPA execution condition(s).

[0192]

[0193] The above-mentioned cell information or cell identity information contains a cell identity, frequency information, and / or a tracking area identity. The cell identity may be a global cell identity or a physical cell identity.

[0194] The failure may be a radio link failure RLF or SCG failure or other failure. The RLF Report includes one or more of the above information. The SCG failure information includes one or more of the above-described information. The other failure information includes one or more of the above-described information.

[0195] For the case that a SCG failure occurs after a RLF or a RLF failure occurs after a SCG failure, the UE has the following ways to save the failure information: the UE saves all related failure information in the RLF Report; or the UE saves all the related failure information in the SCG failure information; or the UE saves all the related failure information in a newly defined failure information; or the RLF Report contains the SCG failure information (SCGFailureInfomration); or the SCG failure information contains the RLF Report; or the UE saves the RLF Report and the SCG failure information separately. The SCG failure information may be stored in the UE for a period of time, for example, 48 hours. The SCG failure information may be transmitted to a master base station serving the UE at the time of the failure or another base station.

[0196] For the way that the UE saves the RLF Report and the SCG failure information separately, the RLF Report contains one or more of the above information, and the SCG failure information includes one or more of the above information.

[0197] The RLF Report comprises cell identity information on the source PCell, cell identity information of the source PSCell, a C-RNTI of the UE in the source PCell, a C-RNTI of the UE in the source PSCell, time since when CHO with candidate SCG(s) configuration is received by the UE , time from the CHO execution to reporting the RLF Report, and / or time from the UE receiving CHO with candidate SCG(s) configuration to the UE sending SCG failure information to the base station, or time from the UE receiving CHO with candidate SCG(s) the configuration to the UE receiving a request for the SCG failure information from the base station. The SCG failure information also includes cell identity information on the source PCell, cell identity information of the source PSCell, a C-RNTI of the UE in the source PCell, a C-RNTI of the UE in the source PSCell, time since when CHO with candidate SCG(s) configuration is received by the UE, time from the CHO execution to reporting the SCG Failure Information, and / or time from the UE receiving CHO with candidate SCG(s) configuration to the UE sending SCG failure information to the base station, or time from the UE receiving CHO with candidate SCG(s) the configuration to the UE receiving a request for the SCG failure information from the base station. When the RAN node receives the RLF Report and the SCG failure information, it can know that the RLF Report and the SCG failure information are failure information for the same CHO with candidate SCG(s) according to one or more of the information, so as to associate the RLF Report with the SCG failure information. The RAN node performs corresponding cause detection and / or optimization according to the associated RLF Report and the SCG failures information. The source node may be a master base station configuring the CHO with candidate SCG(s).

[0198] At step 302, the UE connects to a radio access network (RAN) node. The UE may access the RAN node through a radio resource control RRC connection re-establishment procedure or an RRC connection establishment procedure. According to embodiments of the disclosure, the RAN node may be a node or base station that the UE can access and may be a same or different base station or node as or from the node or base station that the UE accessed before a failure occurred, and may be, for example, an eNB, a gNB, a gNB-CU, or the like. For the SCG failure after configuring the CHO with candidate SCG(s), the procedure for connecting to the RAN node is not necessary for the UE in the case that the connection between the UE and the master base station does not fail.

[0199] The UE indicates to the network that there is the information on the failure available. The information on the failure being available may be information on a radio link failure RLF report being available and / or information on a secondary cell group failure being available or information on failures in other forms being available. For the SCG failure after configuring the CHO with candidate SCG(s), UE can directly send the SCG failure information to the connected master base station, and UE does not need to send to the network an indication that failure information is available.

[0200] The UE sends the information on the failure to the RAN node. The UE may send the information on the failure to the RAN node after the RAN node requests the information on the failure. The RAN node may request the UE to report the information on the failure upon receiving an indication from the UE that the information on the failure is available.

[0201] For the way that the UE saves the RLF Report and the SCG failure information separately, UE can send the RLF Report and the SCG failure information to the RAN node through one message or different messages.

[0202] The information on the failure sent by the UE to the RAN node contains the information save by the UE in step 301. According to an embodiment of the disclosure, the information on the failure sent by the UE to the RAN node may also include time information related to the UE sending the information on the failure to the RAN node. For example, the information on the failure sent by the UE to the RAN node may further include one or more of the following:

[0203] - time from the failure to the UE transmitting the information on the failure to the RAN node;

[0204] - time from the CPC execution condition being fulfilled to the UE transmitting the information on the failure to the RAN node;

[0205] - time from the CPA execution condition being fulfilled to the UE transmitting the information on the failure to the RAN node;

[0206] - time from the CHO execution condition being fulfilled to the UE transmitting the information on the failure to the RAN node;

[0207] - time since when CHO with candidate SCG(s) configuration is received by the UE, which is the same as that described in step 301, and will not be repeated here;

[0208] - time from when CHO with candidate SCG(s) configuration is received by the UE to when SCG failure information is sent to the base station, or the time from when CHO with candidate SCG(s) configuration is received by the UE to when a request for SCG failure information is received by the UE from the base station.

[0209] The above failure information can be included in the RLF report and / or the SCG failure information.

[0210] The information on the failure may be an RLF report. The information on the failure may be SCG failure information. The failure information may be newly defined failure information. The SCG failure information may be included in the RLF report, the SCG failure information may comprise the RLF Report, or the UE saves the RLF Report and SCG failure information separately.

[0211] At step 303, the RAN node receives the information on the failure from the UE. The RAN node sends the information on the failure received from the UE to a master base station last serving the UE. The master base station last serving the UE is also the master base station that served the UE before or when the failure occurred. The RAN node may send the information on the failure received from the UE to the master base station last serving the UE through a failure indication message or other message. The RAN node sends information on CHO only being not prepared to the master base station last serving the UE. The RAN node also sends information on a candidate target PSCell fulfilling an execution condition to the master base station last serving the UE. If the RAN node receiving the failure information from the UE is the master base station last serving the UE, forwarding between RAN nodes is not required. If the RAN node receives the RLF Report and the SCG failure information from the UE through different messages, the RAN node may send the RLF Report and the SCG failure information to the master base station last serving the UE through two messages, respectively. The method of associating the RLF Report and the SCG failure information by the master base station last serving the UE is the same as that described in step 301, and will not be repeated here. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node that receives the failure information from the UE can also send the RLF Report and the information on the SCG failure to the master base station last serving the UE through one message. In this case, the RAN node that receives the failure information from the UE needs to associate the RLF Report with the information on the SCG failure, and the specific associating method is the same as that in step 301, which is not repeated here.

[0212] The master base station last serving the UE detects a cause of the failure or a type of the failure. For the SCG failure after configuring the CHO with candidate SCG(s), the master base station that the UE currently is connected to can detect the cause of the failure or the type of the failure, and the master base station that the UE currently is connected to is also the master base station that receives the SCG failure information from the UE. For the SCG failure after configuring the CHO with candidate SCG(s), the target master base station can detect the cause of the failure or the type of the failure. If the source master base station receives the SCG failure information, the source master base station sends the received SCG failure information to the target master base station. For the SCG failure after configuring the CHO with candidate SCG(s), the source master base station can detect the cause of the failure or the type of the failure. If the target master base station receives the SCG failure information, the target master base station sends the received SCG failure information to the source master base station. In the present invention, detecting the cause of the failure can also be referred to as final detection of the cause of the failure or final detection of the root cause of the failure.

[0213] The cause of the failure or the type of the failure includes but is not limited to the following:

[0214] - a too late CHO and CPAC execution;

[0215] - a too late CHO and CPC execution;

[0216] - a too late CHO and CPA execution;

[0217] - a too late PSCell change;

[0218] - a too late CPC execution;

[0219] - a too late CHO execution and a too early CPC or CPA execution;

[0220] - the too late CHO execution and a CPC or CPA execution to a wrong cell;

[0221] - the CHO execution to the wrong cell and a too late CPC or CPA execution;

[0222] - a too early CHO execution and the too early CPC or CPA execution;

[0223] - the CHO execution to the wrong cell and the CPC or CPA execution to the wrong cell;

[0224] - the too early CHO execution and the CPC or CPA execution to the wrong cell;

[0225] - the too early CHO execution and the too late CPAC execution;

[0226] - the CHO execution to the wrong cell and the too early CPC or CPA execution;

[0227] - the too early CPC or CPA execution;

[0228] - the too late CPC or CPA execution;

[0229] - the too late CHO execution or a too late CHO with candidate SCG(s) execution;

[0230] - the too early CHO execution or a too early CHO with candidate SCG(s) execution;

[0231] - the CHO execution to the wrong cell or a CHO with candidate SCG(s) execution to the wrong cell;

[0232] - the CPC or CPA execution to the wrong cell.

[0233] The base station receives the failure information of the UE, and knows whether the PCell fulfilling the CHO execution condition and the PSCell fulfilling the CPC or CPA execution condition are associated according to information on a primary cell that fulfils the conditional handover execution condition, information on one or more candidate PSCells associated with the primary cell that fulfils the conditional handover execution condition, cell identity information of the PSCell that fulfils the CPC or CPA execution condition, and / or cell identity information on a PCell associated with a PSCell that fulfils the CPC or CPA execution conditions. The selection of the PCell or the PSCell is optimized by the source base station that triggers CHO with candidate SCG(s) or the (candidate) target base station.

[0234] Too lateCHOand CPC execution or too lateCHOandCPACexecution:

[0235] if the UE is configured with the CHO or the CHO with SCG(s) or the CHO with candidate SCG, and there is no recent CHO execution or no CHO execution prior to failure and no recent CPC execution or no CPC execution, then the cause of the failure or the type of the failure is the too late CHO and CPC execution, or the too late CHO and CPAC execution. On the basis of the foregoing conditions, the base station may also determine that the cell with which the UE attempts to re-establish the radio link connection is a cell different from the source PCell, that there is a suitable SPCell different from the PSCell serving the UE at the time of the failure, and decide it is the too late CHO and CPC execution or the too late CHO and CPAC execution. The base station knows that there is no recent CHO execution based on either the time from the CHO execution to the failure being absent in the received information on the failure or the received time from the CHO execution to the failure being larger than a configured threshold. The base station knows that there is no recent CPC execution based on either the time from the CPC execution to the failure being absent in the received information on the failure or the received time from the CPC execution to the failure being larger than a configured threshold. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPC execution may be different configured threshold values or the same threshold value. The base station decides to optimize the configuration of the CHO and / or the configuration of the CPAC according to whether the failure information comprises information on a CHO execution condition being fulfilled, whether the failure information comprises information on a CPC execution condition being fulfilled, whether the failure information comprises information on a CPA execution condition being fulfilled, identity information on a first re-establishment attempt cell after a failure, identity information on a cell with which a radio resource control connection is re-established for the first time after a failure, identity information on a cell with which a radio link connection is re-connected successfully, time information from the UE receiving the conditional handover configuration information to the CHO execution condition being fulfilled, time information from the UE receiving the conditional handover configuration information to the CPAC execution condition being fulfilled, and / or cell identity information on a suitable PSCell, and the base station also know how to perform the optimization according to the information.

[0236] Too lateCHOand CPA execution or too lateCHOandCPACexecution:

[0237] if the UE is configured with the CHO or the CHO with SCG or the CHO with candidate SCG, and there is no recent CHO execution or no CHO execution prior to failure, and no recent CPA execution or no CPA execution, then the cause of the failure or the type of the failure is the too late CHO and CPC execution, or the too late CHO and CPAC execution. On the basis of the foregoing conditions, the base station may also determine that the cell with which the UE attempts to re-establish the radio link connection is a cell different from the source PCell, that there is a suitable SPCell different from the PSCell serving the UE at the time of the failure, and determine it is the too late CHO and CPA execution or the too late CHO and CPAC execution. The base station knows that there is no recent CHO execution based on either the time from the CHO execution to the failure being absent in the received information on the failure or the received time from the CHO execution to the failure being larger than a configured threshold. The base station knows that there is no recent CPA execution based on either the time from the CPA execution to the failure being absent in the received information on the failure or the received time from the CPA execution to the failure being larger than a configured threshold. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPA execution may be different configured threshold values or the same threshold value. The base station decides to optimize the configuration of the CHO and / or the configuration of the CPAC according to whether the failure information comprises information on a CHO execution condition being fulfilled, whether the failure information comprises information on a CPC execution condition being fulfilled, whether the failure information comprises information on a CPA execution condition being fulfilled, identity information on a cell with which a radio link connection is re-established for the first time after a failure, identity information on a cell with which a radio resource control connection is re-established for the first time after a failure, identity information on a cell with which a radio link connection is re-established successfully, time information from the UE receiving the conditional handover configuration information to the CHO execution condition being fulfilled, time information from the UE receiving the conditional handover configuration information to the CPAC execution condition being fulfilled, and / or cell identity information on a suitable PSCell, and the base station also know how to perform the optimization according the information.

[0238] Too lateCHOandCPACexecution:

[0239] if the UE is configured with the CHO or the CHO with SCG or the CHO with candidate SCG, and there is no recent CHO execution or no CHO execution prior to a failure, and no recent CPAC execution or no CPAC exeuction, then the cause of the failure or the type of the failure is the too late CHO and CPAC execution. On the basis of the preceding conditions, the base station may also determine that the cell with which the UE attempts to re-establish the radio link connection is a cell different from the source PCell, that there is a suitable SPCell different from the PSCell serving the UE at the time of the failure, and determine that it is the too late CHO and CPAC execution. The base station knows that there is no recent CHO execution based on either the time from the CHO execution to the failure being absent in the received information on the failure or the received time from the CHO execution to the failure being larger than a configured threshold. The base station knows that there is no recent CPAC execution based on either the time from the CPAC execution to the failure being absent in the received information on the failure or the received time from the CPAC execution to the failure being larger than a configured threshold. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPAC execution may be different configured threshold values or the same threshold value. The base station decides to optimize the configuration of the CHO and / or the configuration of the CPAC according to whether the failure information comprises information on a CHO execution condition being fulfilled, whether the failure information comprises information on a CPC execution condition being fulfilled, whether the failure information comprises information on a CPA execution condition being fulfilled, identity information on a cell with which a radio link connection is re-established for the first time after a failure, identity information on a cell with which a radio resource control connection is re-established for the first time after a failure, identity information on a cell with which a radio link connection is re-established successfully, time information from the UE receiving the conditional handover configuration information to the CHO execution condition being fulfilled, time information from the UE receiving the conditional handover configuration information to the CPAC execution condition being fulfilled, and / or cell identity information on a suitable PSCell, and the base station also know how to perform the optimization according the information

[0240] Too lateCHOand too early CPC or CPA execution:

[0241] if the UE is configured with the CHO or the CHO with SCG or the CHO with candidate SCG, there is no recent CHO execution or no CHO execution prior to a failure, and the CPC or CPA execution condition is fulfilled before the failure, then the cause of the failure or the type of the failure is the too late CHO and the too early CPC or CPA execution. The base station knows that there is no recent CHO execution based on either the time from the CHO execution to the failure being absent in the received information on the failure or the received time from the CHO execution to the failure being larger than a configured threshold. The base station knows that the CPC or CPA execution condition is fulfilled before the failure based on the information on the CPC or CPA execution condition being fulfilled being present in the received information on the failure.

[0242] Too lateCHOand CPC or CPA execution to wrong cell:

[0243] if the UE is configured with the CHO or the CHO with SCG or the CHO with candidate SCG, there is no recent CHO execution or no CHO execution prior to a failure, and the CPC or CPA execution condition is fulfilled before the failure, and a PSCell that fulfils the CPC or CPA execution condition is not a suitable cell, then the cause of the failure or the type of the failure is the too late CHO and the CPC or CPA execution to the wrong cell. The base station knows that there is no recent CHO execution based on either the time from the CHO execution to the failure being absent in the received information on the failure or the received time from the CHO execution to the failure being larger than a configured threshold. The base station knows that the CPC or CPA execution condition is fulfilled before the failure and the PSCell in which the CPC or CPA execution condition is fulfilled is not a suitable cell, based on the information on the CPC or CPA execution condition being fulfilled being present in the received information on the failure, the cell identity / ID information of the PSCell in which the CPC or CPA execution condition is fulfilled and / or the measurement result.

[0244] CHOto wrong cell and too late CPC or CPA execution:

[0245] the CHO execution condition is fulfilled before the failure, the cell in which the CHO execution condition is fulfilled is not a suitable cell, if the UE is configured with the CHO with candidate SCG, and there is no recent CPC or CPA execution, then the cause of the failure or the type of the failure is the CHO to the wrong cell and the too late CPC or CPA execution. The base station knows that the CHO execution condition is fulfilled before the failure and the PSCell in which the CPC or CPA execution condition is fulfilled is not a suitable cell, based on the information on the CHO execution condition being fulfilled being present in the received information on the failure, the cell identity / ID information of the PCell in which the CHO execution condition is fulfilled and / or the measurement result. The base station knows that there is no recent CPC or CPA execution based on either the time from the CPC or CPA execution to the failure being absent in the received information on the failure or the received time from the CPC or CPA execution to the failure being larger than a configured threshold.

[0246] Too earlyCHOexecution and too early CPC execution:

[0247] there are a recent CHO execution and CPC execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, the CPC execution fails or the SCG failure occurs shortly after the successful CPC execution, the cell with which the UE attempts to re-establish a radio resource control connection is the source PCell or the cell to which the UE successfully re-connects is the source Pcell, and the source PSCell is a suitable cell, then the cause of the failure or the type of the failure is the too early CHO execution and the too early CPC execution. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPC execution based on the time from the CPC execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement results. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide the suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPC execution may be different configured threshold values or the same threshold value.

[0248] Too earlyCHOexecution and too early CPA execution:

[0249] there are a recent CHO execution and CPA execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, and the CPA execution fails or the SCG failure occurs shortly after the successful CPA execution, the cell with which the UE attempts to re-establish a radio resource control connection is the source PCell or the cell to which the UE successfully re-connects is the source cell, and there is no suitable PSCell, then the cause of the failure or the type of the failure is the too early CHO execution and the too early CPA execution. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPA execution based on the time from the CPA execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows there is no suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPA execution may be different configured threshold values or the same threshold value.

[0250] CHOexecution to wrong cell and CPA execution to wrong cell:

[0251] there are a recent CHO execution and CPA execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, and the CPA execution fails or the SCG failure occurs shortly after the successful CPA execution, the cell with which the UE first attempts to re-establish a radio resource control connection or to which the UE attempts to re-connect or in which the CHO is recovered is not the source PCell of the last handover or the target PCell or a cell serving the UE when the RLF occurs, and the suitable PSCell is not the source PSCell or the target PSCell, then the cause of the failure or the type of the failure is the CHO execution to the wrong cell and the CPA execution to wrong cell. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPA execution based on the time from the CPA execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPA execution may be different configured threshold values or the same threshold value.

[0252] CHOexecution to wrong cell and CPC execution to wrong cell:

[0253] there are a recent CHO execution and CPC execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, and the CPC execution fails or the SCG failure occurs shortly after the successful CPC execution, the cell with which the UE first attempts to re-establish a radio resource control connection or to which the UE attempts to re-connect or in which the CHO is recovered is not the source PCell of the last handover or the target PCell, and the suitable PSCell is not the source PSCell or the target PSCell or a cell serving the UE when the RLF occurs, then the cause of the failure or the type of thefailure is the CHO execution to the wrong cell and the CPC execution the the wrong cell. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPC execution based on the time from the CPC execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent CPC execution may be different configured threshold values or the same threshold value.

[0254] Too earlyCHOexecution and CPC or CPA execution to wrong cell:

[0255] there are a recent CHO execution and CPC or CPA execution before the failure. If the CHO execution fails or RLF occurs shortly after the successful CHO execution, the cell with which the UE attempts to re-establish a radio resource control connection is the source PCell or the cell to which the UE successfully re-connects is the source cell, the CPC or CPA execution fails or the SCG failure occurs shortly after the successful CPC or CPA execution, the suitable PSCell is not the source PSCell or the target PSCell, then the cause of the failure or the type of the failure is the too early CHO execution and the CPC or CPA execution to the wrong cell. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPC or CPA execution based on the time from the CPC or CPA execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent or CPC or CPA execution may be different configured threshold values or the same threshold value.

[0256] CHOexecution to wrong cell and too early CPC execution:

[0257] there are a recent CHO execution and CPC execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, the cell with which the UE first attempts to re-establish a radio resource control connection after the failure or to which the UE attempts to re-connect or in which the CHO is recovered is not the source PCell of the last handover or the target PCell or a cell serving the UE when the RLF occurs, the CPC execution fails or the SCG failure occurs shortly after the successful CPC execution, and the source PSCell is a suitable cell, then the cause of the failure or the type of the failure is the CHO execution to the wrong cell and the too early CPC execution. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPC execution based on the time from the CPC or execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent or CPC execution may be different configured threshold values or the same threshold value.

[0258] CHOexecution to wrong cell and too early CPA execution:

[0259] there are a recent CHO execution and CPA execution before the failure. If the CHO execution fails or the RLF occurs shortly after the successful CHO execution, the cell with which the UE first attempts to re-establish a radio resource control connection or to which the UE attempts to re-connect after the failure or in which the CHO is recovered is not the source PCell of the last handover or the target PCell or a cell serving the UE when the RLF occurs, the CPA execution fails or the SCG failure occurs shortly after the successful CPA execution, and there is no suitable PSCell, then the cause of the failure or the type of the failure is the CHO execution to the wrong cell and the too early CPA execution. The base station knows that there is the recent CHO execution based on the time from the CHO execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows that there is the recent CPA execution based on the time from the CPA execution to the failure in the received information on the failure being smaller than a configured threshold. The base station knows the suitable PSCell from the measurement result. According to embodiments of the disclosure, the measurement result may be reported by the UE. Other information may also be considered to decide whether there is a suitable PSCell. According to an embodiment of the disclosure, the configured threshold value for determining whether there is the recent CHO execution and the configured threshold value for determining whether there is the recent or CPA execution may be different configured threshold values or the same threshold value.

[0260] Too earlyCHOexecution and too lateCPACexecution:

[0261] There is a recent CHO execution prior to the failure. If a CHO execution fails or an RLF occurs shortly after a successful CHO execution, the UE attempts to re-establish the radio resource control connection in the source PCell or the cell to which UE successfully re-connects is the source cell, and the base station knows that there is a recent CHO execution according to the time from the CHO execution to the failure in the received failure information being smaller than a configured threshold. The base station knows that there is no recent CPC or CPA execution according to that the time from the CPA or CPC execution to the failure is absent in the received failure information, or the time from the CPA or CPC execution to the failure is greater than a configured threshold. The cause or type of failure is too early CHO execution and too late CPAC execution.

[0262] Too lateCHOor too lateCHOwith candidateSCG(s):

[0263] If the UE is configured with CHO or CHO with SCG or CHO with candidate SCG(s), and there is no recent CHO execution prior to the failure or there is no CHO execution prior to the failure or there is no CHO and CPC execution prior to the failure or the CHO execution condition is not fulfilled or the CHO execution condition is fulfilled after the CPAC execution condition is fulfilled, the UE fails, which may be a RLF failure and / or a SCG failure, then the cause of failure or a type of failure is the too late CHO or the too late CHO with candidate SCG(s). On the basis of the foregoing conditions, the base station may also determine that the cell with which the UE attempts to re-establish the radio link connection is a cell different from the source PCell, and determine that it is the too late CHO or the too late CHO with candidate SCG(s). The base station decides to optimize the configuration of the CHO and / or the configuration of the CPAC according to whether the failure information comprises information on a CHO execution condition being fulfilled, whether the failure information comprises information on a CPC execution condition being fulfilled, whether the failure information comprises information on a CPA execution condition being fulfilled, identity information on a cell with which a radio link connection is re-established for the first time after the failure, identity information on a cell with which a radio resource control connection is re-established for the first time after a failure, identity information on a cell with which a radio link connection is re-established successfully, and / or cell identity information on a suitable PSCell. The base station knows that there is no recent CHO execution according to that the time from the CHO execution to the failure is absent in the received failure information, or the received time from the CHO execution to the failure is greater than a configured threshold. The base station knows that the CHO execution conditions are not fulfilled according to the information that the CHO execution conditions are fulfilled is absent in the received failure information, and thus knows that the failure is caused by the CHO execution conditions. The base station knows that the CHO execution conditions and CPC or CPA execution conditions are not fulfilled according to the information that the CHO execution conditions are fulfilled and the information that the CPC or CPA execution conditions are fulfilled are absent in the received failure information,, and thus knows that the failure is caused by the CHO execution conditions and / or the CPC or CPA execution conditions. The base station knows that the CPA or the CPC execution conditions are not fulfilled according to the information that the CPA or the CPC execution conditions are fulfilled is absent in the received failure information, and thus knows that the failure is caused by the CPA or the CPC execution conditions and / or the CHO execution conditions. The base station knows whether the CHO execution conditions need to be optimized or whether the failure is related to the configuration of the CHO execution conditions according to the time information from configuring CHO with candidate SCG(s) to the conditional handover execution conditions being fulfilled, the time from configuring the CHO with candidate SCG(s) to the failure, and / or the time information from the CHO execution conditions being fulfilled to the failure. The base station may know that the CHO execution conditions are not fulfilled based on that time information from configuring the conditional handover to the conditional handover execution conditions being fulfilled, information on the conditional handover event that fulfils the execution condition, information on the primary cell that fulfils the conditional handover execution conditions, information on an event or a type of a first execution condition(s) being fulfilled, information on the event that fulfils the execution condition, time information from configuring the CHO with candidate SCG(s) to the execution condition being fulfilled, and time information from the CHO execution conditions being fulfilled to the failure are absent in the received failure information. The base station may know that the CPA or CPC execution conditions are not fulfilled based on that the received failure information does not include time information from configuring the conditional handover to the CPA or CPC execution conditions being fulfilled, information on the CPC or CPA execution conditions being fulfilled, information on an event that fulfils the CPC or CPA execution conditions, cell identity information of a PSCell that fulfils the CPC or CPA execution conditions, information on an event or a type of a first execution condition(s) being fulfilled, information on the event that fulfils the execution conditions, time information from configuring the CHO with candidate SCG(s) to the execution conditions being fulfilled, or time information from the CPAC execution conditions being fuflfilled to the failure. The base station knows that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to the time information from configuring a condition handover to the condition handover execution conditions being fulfilled and the time information from configuring the condition handover to the CPA or CPC execution conditions being fulfilled in the received failure information, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to time information from the CHO execution conditions being fulfilled to the failure and time information from the CPAC execution conditions being fulfilled to the failure in the received failure information, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to that the indication information that the CHO execution conditions and the CPC or CPA execution conditions are fulfilled simultaneously is absent, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to time difference between the two execution conditions being fulfilled in the received failure information, and thus the base station knows the failure is caused by the CHO execution conditions and / or the CPC or CPA execution conditions. According to the indication information of the CHO with candidate SCG(s) in the received failure information or according to the UE context, the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and knows that the CPAC configuration information may need to be optimized while optimizing of the CHO configuration information. The base station knows that the CHO execution condition is fulfilled after the CPAC execution condition is fulfilled according to the time information from configuring the conditional handover to the conditional handover execution condition being fulfilled and the time information configuring the conditional handover to the CPAC execution condition being fulfilled in the received information, or knows that the CHO execution condition is fulfilled after the CPAC execution condition is fulfilled according to the time information from CHO execution conditions being fulfilled to the failure and the time from CPAC execution conditions being fulfilled to the failure. The base station knows that the CHO execution condition is fulfilled after the CPAC execution condition is fulfilled according to that the time information from configuring the conditional handover to the conditional handover execution condition being fulfilled is greater than time information from configuring the conditional handover configuration to the CPAC execution condition being fulfilled, or knows that the CHO execution condition is fulfilled after the CPAC execution condition is fulfilled according to that time information that from the CHO execution condition being fulfilled to the failure is less than time information from the CPAC execution condition being fulfilled to the failure.

[0264] Too late CPC execution:

[0265] If the UE is configured with CPC or CHO with candidate SCG(s), there is no recent CPC execution prior to the failure, or there is no CHO and CPC execution prior to the failure or there is no recent CHO and CPC execution, and there is a suitable PSCell different from the PSCell where the UE accesses at the time of the failure, the cause of failure or the type of failure is the too late CPC execution. The base station decides to optimize the configuration of the CHO and / or the configuration of the CPAC according to whether the failure information comprises information on a CHO execution condition being fulfilled, whether the failure information comprises information on a CPC execution condition being fulfilled, whether the failure information comprises information on a CPA execution condition being fulfilled, identity information on a cell with which a radio link connection is re-established for the first time after the failure, identity information on a cell with which a radio resource control connection is re-established for the first time after the failure, identity information on a cell with which a radio link connection is re-established successfully, and / or cell identity information on a suitable PSCell. The base station knows that there is no recent CPC execution according to that the time from the CPC execution to the failure is absent in the received failure information, or the received time from the CPC execution to the failure is greater than a configured threshold. According to an embodiment of the disclosure, the threshold value for determining whether there is a recent CHO execution and the threshold value for determining whether there is a recent CPAC execution may be configured different threshold values or the configured same threshold value. If the UE is configured with CHO with candidate SCG(s), the configuration of the candidate PSCell and / or the configuration of the candidate PCell may need to be optimized, specifically, the configuration of the candidate PSCell may need to be optimized and / or the configuration of the candidate PCell associated with the candidate PSCell may need to be optimized, specifically, the execution conditions of the candidate PSCell may need to be optimized and / or the execution conditions of the candidate PCell associated with the candidate PSCell may need to be optimized. The base station knows that the CHO execution conditions and the CPC execution conditions are not fulfilled according to that the information that the CHO execution conditions being fulfilled and the information that the CPC execution conditions being fulfilled are absent in the received failure information, and thus knows that the failure is caused by the CHO execution conditions and / or the CPC execution conditions, thereby optimizing the corresponding execution conditions, and the base station may also configure a PSCell change procedure instead of configuring the CHO with candidate SCG(s) to avoid future failures. The base station knows that the CHO execution conditions are not fulfilled based on that the information on the CHO execution conditions being fulfilled is absent in the received failure information, and thus knows that the failure is caused by the CHO execution conditions, and the base station decides whether the failure is also related to the configuration of the CPC based on the time information from configuring the CHO with candidate SCG(s) to the CPC execution conditions being fulfilled and the time from configuring the CHO with candidate SCG(s) to the failure, or the base station decides whether the failure is also related to the configuration of the CPC based on the time information from the CPC execution conditions being fulfilled to the failure, so as to optimize the CHO configuration and / or the CPC configuration accordingly. The base station knows that the CPC execution conditions are not fulfilled according to the received failure information not comprising the information on the CPC execution conditions being fulfilled, thereby knowing that the failure is caused by the CPC execution conditions and / or the CHO execution conditions, and the base station knows whether the CHO execution conditions need to be optimized or whether the failure is related to the configuration of the CHO execution conditions according to the time information from configuring the CHO with candidate SCG(s) to the conditional handover execution conditions being fulfilled, the time from configuring the CHO with candidate SCG(s) to the failure, and / or the time information from the CHO execution conditions being fulfilled to the failure. The base station may know that the CHO execution conditions are not fulfilled based on that the received failure information does not include time information from configuring the conditional handover to the conditional handover execution conditions being fulfilled, information on a conditional handover event that fulfils the execution conditions, information on a primary cell that fulfils the conditional handover execution conditions, information on an event or a type of a first execution condition(s) being fulfilled, information on the event that fulfils the execution conditions, time information from configuring the CHO with candidate SCG(s) to the execution conditions being fulfilled, or time information from the CPAC execution conditions being fuflfilled to the failure. The base station may know that the CPC execution conditions are not fulfilled based on that the received failure information does not comprises time information from configuring the conditional handover to the CPA or CPC execution conditions being fulfilled, information on the CPC or CPA execution conditions being fulfilled, information on an event that fulfils the CPC or CPA execution conditions, cell identity information of a PSCell that fulfils the CPC or CPA execution conditions, information on an event or a type of a first execution condition(s) being fulfilled, information on the event that fulfils the execution conditions, time information from configuring the CHO with candidate SCG(s) to the execution conditions being fulfilled, or time information from the CPC execution conditions being fuflfilled to the failure. The base station knows that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to the time information from configuring a condition handover to the condition handover execution conditions being fulfilled and the time information from configuring the condition handover to the CPA or CPC execution conditions being fulfilled in the received failure information, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to time information from the CHO execution conditions being fulfilled to the failure and time information from the CPAC execution conditions being fulfilled to the failure in the received failure information, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to that the indication information that the CHO execution conditions and the CPC or CPA execution conditions are fulfilled is absent, the base station may also know that the CHO execution conditions and the CPC or CPA execution conditions are not fulfilled simultaneously according to time difference between the two execution conditions being fulfilled in the received failure information, and thus the base station knows the failure is caused by the CHO execution conditions and / or the CPC or CPA execution conditions. According to the indication information on the CHO with candidate SCG(s) in the received failure information or according to the UE context, the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and know the configuration information of the CHO may need to be optimized while optimizing the CPC configuration information.

[0266] Too earlyCHOor too earlyCHOwith candidateSCG(s):

[0267] There is a recent CHO execution prior to the failure. If the CHO execution fails, or an RLF occurs shortly after the successful CHO execution, or the CHO execution conditions are fulfilled before the CPAC execution conditions are fulfilled, the UE attempts to re-establish the radio link connection in the source PCell of the last handover or the cell to which the UE successfully re-connects is source cell of the last handover, then the cause or type of failure is the too early CHO or the too early CHO with candidate SCG(s). The cell with which the UE attempts to re-establish the radio link connection is the cell with which the UE attempts to re-establish the radio link connection for the first time after the failure. The cell to which the UE successfully re-connects is the cell to which the UE successfully reconnects for the first time after the UE fails. The base station knows that there is the recent CHO execution according to the time from the CHO execution to the failure in the received failure information being smaller than a configured threshold value. The base station knows that the CHO execution conditions are fulfilled according to that the information on the CHO execution conditions being fulfilled is present in the received failure information. The base station knows that the CHO execution condition is fulfilled before the CPAC execution condition is fulfilled according to the time information from configuring the conditional handover to the conditional handover execution conditions being fulfilled and the time information from configuring the conditional handover to the CPAC execution condition being fulfilled in the received information, or knows that the CHO execution condition is fulfilled before the CPAC execution condition being fulfilled according to the time information from CHO execution condition being fulfilled to the failure and the time from CPAC execution condition being fulfilled to the failure. The base station knows that the CHO execution condition is fulfilled before the CPAC execution condition is fulfilled according to that the time information from configuring the conditional handover to the conditional handover execution conditions being fulfilled is smaller than the time information from configuring the conditional handover configuration to the CPAC execution conditions being fulfilled, or knows that the CHO execution condition is fulfilled before the CPAC execution condition is fulfilled according to that the time information from the CHO execution condition being fulfilled to the failure are greater than the time from CPAC execution condition being fulfilled to the failure. For the failure caused by the configuration of the CHO with candidate SCG(s), the configuration of the CHO needs to be optimized and / or the configuration of the CPAC needs to be optimized, or the configuration of the CHO needs to be optimized and / or the configuration of the associated CPAC needs to be optimized, specifically, the execution conditions of the CHO and / or the execution conditions of the CPAC need to be optimized, and the execution conditions of the CPAC may be the execution conditions of the candidate PSCell associated with the candidate PCell of the CHO. According to the indication information on the CHO with candidate SCG(s) in the received failure information or according to the UE context, the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and know that the configuration information of the CPAC may need to be optimized while optimizing the CHO configuration information.

[0268] CHOexecution to wrong cell orCHOwith candidateSCG(s) execution to wrong cell:

[0269] There is a recent CHO execution prior to the failure. If the CHO execution fails, or an RLF occurs shortly after a successful CHO execution, the cell with which the UE attempts to re-establish the radio link connection or the cell to which the UE attempts to reconnect or the cell in which the UE attempts the CHO recovery is neither the source PCell of the last handover nor the cell serving the UE at the time of the RLF or the target PCell of the last handover, then the cause of failure or the type of failure is the CHO execution to the wrong cell or the CHO with candidate SCG(s) execution to the wrong cell. The base station knows that there is the recent CHO execution according to the time from the CHO execution to the failure in the received failure information being smaller than a configured threshold value. The cell with which the UE attempts to re-establish the radio link connection is the cell with which the UE attempts to re-establish the radio link connection for the first time after the failure. The cell to which the UE attempts to reconnect is the cell to which the UE attempts to reconnect for the first time after the failure. The cell in which the UE attempts the CHO recovery is the cell in which the UE attempts the CHO recovery for the first time after the UE fails. For the failure caused by the configuration of the CHO with candidate SCG(s), the configuration of the CHO needs to be optimized and / or the configuration of the CPAC needs to be optimized, or the configuration of the CHO needs to be optimized and / or the configuration of the associated CPAC needs to be optimized, specifically, the execution conditions of the CHO and / or the execution conditions of the CPAC needs to be optimized, and the execution conditions of the CPAC may be the execution conditions of the candidate PSCell associated with the candidate PCell of the CHO. According to the indication information on the CHO with candidate SCG(s) in the received failure information or according to the UE context, the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and knows the configuration information of the CPAC may need to be optimized while optimizing the CHO configuration information.

[0270] Too early CPC or CPA execution:

[0271] There is a recent CPC or CPA execution prior to the failure, the source PSCell is a suitable PSCell in case of the CPC, and no suitable PSCell in case of CPA. The base station knows that there is a recent CPC execution according to the time from the CPC execution to the failure in the received failure information being smaller than a configured threshold. The too early CPC or CPA execution may be an unsuccessful CPC or CPA execution or an SCG failure that occurs shortly after a successful CPC or CPA execution. The base station knows the suitable PSCell according to the measurement report of the UE. According to the indication information on the CHO with candidate SCG(s) in the received failure information or according to the UE context the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and knows the configuration information of the CHO may need to be optimized while optimizing the CPC configuration information.

[0272] CPC or CPA execution to wrong cell:

[0273] There is a recent CPC or CPA execution prior to the failure, and the suitable PSCell is not the source PSCell or the target PSCell. The base station knows that there is a recent CPC execution according to the time from the CPC execution to the failure in the received failure information being smaller than a configured threshold. The CPC or CPA execution to the wrong cell may be an unsuccessful CPC or CPA execution or an SCG failure that occurs shortlyafter a successful CPC or CPA execution. The base station knows the suitable PSCell according to the measurement report of the UE. If the suitable PSCell is a cell in the candidate PSCells provided by the node triggering the CPC or a cell in the candidate PSCells provided by the MN triggering the CPA, but not a cell among the candidate PSCells selected by the candidate or target SN, then it is a wrong target PSCell selection by the candidate or target SN, otherwise it is a wrong candidate PSCell list selection by the node triggering the CPC or the MN triggering the CPA. According to the indication information on the CHO with candidate SCG(s) in the received failure information or according to the UE context the base station knows the failure is caused by the inappropriate configuration of the CHO with candidate SCG(s), and knows the configuration information of the CHO may need to be optimized while optimizing the CPC configuration information.

[0274]

[0275] If it is detected that the problem is caused by other base station, the master base station last serving the UE sends a message to the base station by which the problem is caused. The base station that causes the problem performs optimization.

[0276] If the master base station last serving the UE is the source master base station, e.g., in the case of no CHO execution, no CPC execution, and / or no CPA execution, or in the case of the CHO execution failure, the CPC execution failure, and / or the CPA execution failure, the master base station last serving the UE sends a message to the target master base station or the candidate target master base station of the conditional handover or a target secondary base station or the candidate target secondary base station if it is detected that the failure was caused by a target master base station or a candidate target master base station or a target secondary base station or a candidate target secondary base station. The target master base station of the conditional handover is the target master base station of the last conditional handover. The target master base station of the conditional handover may also be a candidate target master base station of the conditional handover. The target secondary base station of the conditional handover can also be a candidate target secondary base station. For example, if the suitable PSCell is not a candidate PSCell recommended / provided by the target master base station or the execution condition for the candidate PSCell is not configured reasonably, the failure is caused by the target master base station. If the suitable PSCell is a candidate PSCell recommended / provided by the target master base station, not a candidate PSCell selected by a target SN or a candidate SN, the problem is caused by the target SN or the candidate SN, the target master base station sends a message to the target SN or the candidate target SN. If the target master base station or the candidate target master base station didn't configure CHO only, the CHO execution condition is fulfilled, no execution condition for the candidate PSCell is fulfilled, and / or there is no suitable PSCell, then the problem is caused by the target master base station or the candidate target master base station, for example, because of the target master base station or the candidate target master base station did not configure CHO only. If the target master base station or the candidate target master base station configured CHO only, a failure will not occur. The candidate PSCell is a candidate PSCell associated with the PCell that fulfils the CHO execution conditions.

[0277] The conditional handover in the present invention includes the CHO with candidate SCG(s). The CPC or CPA in the present invention includes a CPC or CPA procedure in the CHO with candidate SCG(s). The source master base station of the conditional handover is also the source master base station of the CHO with candidate SCG(s). The target master base station of the conditional handover is also the target master base station of the CHO with candidate SCG(s).

[0278] The message sent to the base station causing the problem or the message send to the target master base station of the conditional handover contains one or more of the following information:

[0279] - information on the failure received from the UE, which may be the RLF report and / or the SCG failure information;

[0280] - a cause or a type of the failure. The cause or the type of the failure is also a type of a handover report. The cause or the type of the failure or the type of the handover report can be a too late handover, a too early handover, or a handover to a wrong cell;

[0281] - a list of candidate PSCell information. The candidate PSCell information contains a PSCell identity and an execution condition for the PSCell;

[0282] - information on CHO only being not configured;

[0283] - a UE identity. The UE identity may be a master node (MN) UE application protocol (AP) identity (ID) allocated by the target master base station or the candidate target master base station or the MN UE AP ID allocated by the source master base station and other UE identity. According to embodiments of the disclosure, the message sent by the source master base station to the target master base station or the candidate target master base station may be a non-UE associated message, and the message sent by the target master base station to the target SN or the message sent by the candidate target master base station to the candidate target SN may be a UE associated message. Including the UE ID in the message sent by the source master base station to the target master base station or the candidate target master base station enables the target master base station to know which UE the information on the failure is about, so as to be able to send to the SN through a UE-associated message when there is a need to send a message to the target SN or the candidate target SN, thereby making it feasible for the target master base station or the target MN to send a message to the target SN and maximizing reuse of existing messages, reducing an impact on the specifications.

[0284] For a SCG failure, the message sent to the base station causing the problem or the message sent to the target master base station of the conditional handover may be a failure indication message, a handover report message, an access and mobility indication message, a newly defined message or other messages. For a handover failure or an RLF, the message sent to the base station causing the problem or the message sent to the target master base station of the conditional handover may be a handover report message or other messages.

[0285]

[0286] In the present invention, in the case that the master base station last serving the UE detects the too late handover, the problem can be caused by other base stations, and the master base station last serving the UE sends a message to the base station causing the problem. The message comprises the cause of the failure or the type of the failure or the type of the handover report is the too late handover. For example, for the too late handover in the CHO with candidate SCG(s), if the CHO execution conditions are fulfilled, the CPC or CPA execution conditions are not fulfilled, and the CHO only is not configured, resulting in that the CHO cannot be performed and leads to a too late handover, then the problem is caused by the target master base station. The master base station (the source master base station) last serving the UE sends a message to the target master base station. The message includes the RLF report received from the UE, the cause or the type of the failure or the type of the handover report. The cause or the type of the failure or the type of the handover report is a too late handover.

[0287] The master base station last serving the UE may be a target master base station or a candidate target master base station. If the target master base station or the candidate target master base station detects that the problem is caused by the target secondary node (SN) or the candidate target SN, the target master base station sends a message to the target SN or the candidate target SN. The message may be an SCG failure information report. The message includes one or more of the following information:

[0288] - a cause or a type of the failure;

[0289] - information on the failure received from the UE;

[0290] - information on a candidate PSCell list. The candidate PSCells may be a PSCell list recommended / provided by the target MN, and / or a PSCell list selected by the target SN or the candidate target SN;

[0291] - cell identity / ID information on a suitable PSCell;

[0292] - indication information on being selected by the target SN or the candidate target SN among the PSCells recommended / provided by the target MN;

[0293] - a UE identity. The UE identity can be the MN UE AP ID allocated by the target master base station or the candidate target master base station or other UE identity. The UE identity is received from a source master base station or obtained from a UE context.

[0294] For example, if a suitable PSCell is a candidate PSCell recommended / provided by the target master base station, but not a candidate PSCell selected by the target SN or the candidate target SN, then the problem is caused by the target SN or the candidate target SN.

[0295] If the master base station last serving the UE is the target master base station, for example, in the case where the failure occurs shortly after the successful handover, then the master base station last serving the UE sends a message to the source base station of the conditional handover if it is detect that the failure is caused by the source master base station. The source base station of the conditional handover is the source base station of the last conditional handover. The source base station of the conditional handover is also a source master base station of the conditional handover. For example, the cell with which the UE attempts to re-establish the radio link connection or the cell where the CHO is recovered is not a candidate target cell or the CHO execution condition is configured unreasonably, the problem is caused by the source base station. The message contains one or more of the following information:

[0296] - information on the failure received from the UE, which may be the RLF report and / or the SCG failure information.;

[0297] - a cause or a type of the failure. The cause or the type of the failure is also a type of a handover report. The cause or the type of the failure or the type of the handover report can be a too late handover, a too early handover, or a handover to a wrong cell;

[0298] - cell identity information of a source cell of the last handover;

[0299] - cell identity information of the failed cell;

[0300] - a UE identity. The UE identity may be a master node (MN) UE application protocol (AP) identity (ID) allocated by the target master base station or a candidate target master base station, or the MN UE AP ID allocated by the source master base station or other UE identity.

[0301] For a SCG failure, the message sent to the base station causing the problem or the message sent to the target master base station of the conditional handover may be a failure indication message, a handover report message, an access and mobility indication message, a newly defined message or other messages. For a handover failure or an RLF, the message sent to the base station causing the problem or the message sent to the target master base station of the conditional handover may be a handover report message or other messages.

[0302] If the target master base station or the candidate target master base station detects that the problem is caused by the target secondary node (SN) or the candidate target SN, then the target master base station sends a message to the target SN or the candidate target SN. For example, if a suitable PSCell is a candidate PSCell recommended / provided by the target master base station, but not a candidate PSCell selected by the target SN or the candidate target SN, then the problem is caused by the target SN or the candidate target SN. The information in the message is the same as above, and will not be repeated here.

[0303] Heretofore, the method for supporting self-configuration self-optimization of the disclosure is completed, by which the mobility robustness of a conditional handover with a secondary node can be supported, and the cause of the failure can be correctly identified in case that the failure is caused by a conditional handover or a conditional handover with an SCG or a conditional handover with a candidate SCG, so as to make reasonable optimization, avoid occurrence of failure, guarantee continuity of service, and reduce labor cost of an operator.

[0304]

[0305] Figure 4 illustrates embodiment 1 of a method for supporting self-configuration self-optimization in the disclosure.

[0306] In Figure 4, an S-MN represents a source master node, an S-SN represents a source secondary node, a T(C)-MN represents a target (candidate) master node, and a T(C)-SN represents a target (candidate) secondary node. The method comprises the steps of:

[0307] At step 401, the source MN (S-MN) initiates a handover preparation procedure. The handover preparation procedure may be a conditional handover preparation procedure involving an SN. The conditional handover involving the SN includes a conditional handover with an SN (e.g., there is at least one candidate SN) or a conditional handover with at least one candidate SCG.

[0308] At step 402, the source MN sends an RRC reconfiguration message to the UE. The message contains CHO configuration information. The message includes master cell group (MCG) configuration information and SCG configuration information received from the candidate target SN.

[0309] At step 403a, the UE fails. The failure may be an RLF. The UE saves information on the RLF.

[0310] At step 403b, the SCG failure occurs. The UE saves information on the SCG failure. This step is an optional step.

[0311] The UE has the following ways to save failure information: the UE saves all related failure information in a RLF Report; or the UE saves all the related failure information in SCG failure information; or the UE saves all the related failure information in a newly defined failure information; or the RLF Report contains the SCG failure information (SCGFailureInfomration); or the SCG failure information contains the RLF Report; or the UE saves the RLF Report and the SCG failure information separately. The details are the same as in step 301, and will not be described here.

[0312] At step 404, the UE initiates an RRC connection re-establishment procedure or an RRC connection establishment procedure with a RAN node. According to an embodiment of the disclosure, the RAN node may be a node or base station that the UE can access, and may be, for example, an eNB, a gNB or a gNB-CU or the like. The RRC connection re-establishment procedure or the RRC connection establishment procedure is successfully completed. Information on the failure being available at the UE is included in the RRC Connection Re-establishment Complete or RRC Connection Setup Complete message. The information on the failure being available at the UE is the same as that in step 302 and will not be repeated here.

[0313] At step 405, the RAN node sends a UE information request to the UE, to request the UE to report the information on the failure. The UE sends a UE Information Response message to the RAN node. The UE information response message includes the same information as the information on the failure described in step 302, and will not be described in detail herein.

[0314] For the way that the UE saves the RLF Report and the SCG failure information separately, the UE can send the RLF Report and the information on the SCG failure to the RAN node through one message or different messages. The RLF Report and the information on the SCG failure can also be sent to different RAN nodes, for example, the RLF Report is sent to a RAN node different from the source master base station and the target master base station, and the information on the SCG failure is sent to the source master base station.

[0315] At step 406, the RAN node that receives the information on the failure from the UE sends a message to the RAN node that served the UE when or before the failure occurs, e.g., the failure occurrs in the source MN, and the RAN node that receives the information on the failure from the UE sends a message to the source MN. The message contains the information on the failure received from the UE. Both the RLF Report and the SCG failure information can be sent in this way. This step is an optional step. This step is not required if the source MN receives a UE information response from the UE. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node may send the RLF Report and the information on the SCG failure to the RAN node serving the UE at the time of the failure or prior to the failure through two messages, respectively. The method for associating the RLF Report with the information on the SCG failure by the RAN node serving the UE at the time of the failure or prior to the failure is the same as that described in step 301, and will not be repeatedly described here. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node that receives the failure information from the UE can also send the RLF Report and the information on the SCG failure to the master base station last serving the UE through one message. In this case, the RAN node that receives the failure information from the UE needs to associate the RLF Report with the information on the failure SCG, and the specific associating method is the same as that in step 301, which is not repeated here.

[0316] At step 407, the RAN node serving the UE when or before the failure occurs detects the cause of the failure or the type of the failure. The specific cause or type of the failure and the method of detection are the same as those described in step 303, and will not be repeated here.

[0317] At step 408, the RAN node serving the UE when or before the failure occurs sends a message to the target base station or the candidate target base station if it is detected that the target base station or the candidate target base station or the target secondary base station or the candidate secondary base station causes the problem. The message may be an RLF indication message, an HO report message, an access and mobility indication message or other message. The information included in the message are the same as those described in step 303 and will not be repeated here. Note that herein, unless explicitly indicated to the contrary, a master node may also be referred to as a master base station, a secondary node may also be referred to as a secondary base station, a source node may also be referred to as a source base station, a target node may also be referred to as a target base station, other nodes are in the similar situation and may also be referred to as other base stations.

[0318] Heretofore, the embodiment 1 of the method for supporting self-configuration self-optimization of the disclosure has been completed, by which it is possible to support proper identification of the cause of the failure and thus perform reasonable optimization in case that the failure is caused by a conditional handover or a conditional handover with an SCG or a conditional handover with a candidate SCG, so as to avoid occurrence of a failure, guarantee continuity of a service, and reduce a labor cost of an operator.

[0319]

[0320] Figure 5 illustrates embodiment 2 of a method for supporting self-configuration self-optimization in the disclosure.

[0321] In Figure 5, an S-MN represents a source master node, an S-SN represents a source secondary node, a T(C)-MN represents a target (candidate) master node, and a T(C)-SN represents a target (candidate) secondary node. The method comprises the steps of:

[0322] Steps 501 to 502are the same as steps 401 to 402, and the steps are not repeated here.

[0323] At step 503a, the UE fails. The UE fails to execute the CPC or CPA. The UE saves information on an SCG failure.

[0324] At step 503b, the UE fails to execute the CHO. The UE saves information on an RLF.

[0325] The UE saving the information on the failure is the same as that in step 301, and will not be repeated here.

[0326] At step 504, the UE initiates an RRC connection re-establishment procedure or an RRC connection establishment procedure with a RAN node. According to an embodiment of the disclosure, the RAN node may be a node or base station that the UE can access, and may be, for example, an eNB, a gNB or a gNB-CU or the like. The RRC connection re-establishment procedure or RRC connection establishment procedure is successfully completed. Information on the information on the failure being available at the UE is included in the RRC Connection Re-establishment Complete or RRC Connection Setup Complete message. The information on the information on the failure being available at the UE is the same as that in step 302 and will not be repeated here. As another implementation, the UE can also initiate an RRC connection re-establishment procedure or an RRC connection establishment procedure with the source MN.

[0327] At step 505, the RAN node or source MN sends a UE information request to the UE, to request the UE to report the information on the failure. The UE sends a UE information response message to the RAN node or the source MN. The UE information response message includes the same information as the information on the failure described in step 302, and will not be described in detail herein. For the way that the UE saves the RLF Report and the SCG failure information separately, the UE can send the RLF Report and the information on the SCG failure to the RAN node through one message or different messages. The RLF Report and the information on the SCG failure can also be sent to different RAN nodes, for example, the RLF Report is sent to a RAN node different from the source master base station and the target master base station, and the information on the SCG failure is sent to the source master base station.

[0328] At step 506, the RAN node that receives the information on the failure from the UE sends a message to the RAN node serving the UE when or before the failure occurs, e.g., for the handover failure or the CHO execution failure, the RAN node serving the UE when or before the failure occurs is the source MN, and the RAN node that receives the information on the failure from the UE sends a message to the source MN. The message contains the information on the failure received from the UE, the information on the failure received from the UE includes the RLF report and / or the SCG failure information. Both the RLF Report and the SCG failure information can be sent in this way. This step is an optional step. This step is not necessary if the source MN receives the UE information response from the UE. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node may send the RLF Report and the information on the SCG failure to the RAN node serving the UE at the time of the failure or prior to the failure through two messages, respectively. The method for associating the RLF Report with the information on the SCG failure by the RAN node serving the UE at the time of the failure or prior to the failure is the same as that described in step 301, and will not be repeatedly described here. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node that receives the failure information from the UE can also send the RLF Report and the information on the SCG failure to the master base station last serving the UE through one message. In this case, the RAN node that receives the failure information from the UE needs to associate the RLF Report with the information on the failure SCG, and the specific associating method is the same as that in step 301, which is not repeated here.

[0329] At step 507, the RAN node serving the UE when or before the failure occurs detects the cause of the failure or the type of the failure. The specific cause or type of the failure and the method of detection are the same as those described in step 303, and will not be repeated here.

[0330] At step 508, the RAN node serving the UE when or before the failure occurs sends a message to the target base station or the candidate target base station if it is detected that the target base station or the candidate target base station or the target secondary base station or the candidate secondary base station causes the problem. The message may be an RLF indication message, an HO report message, an access and mobility indication message or other message. The information included in the message are the same as those described in step 303 and will not be repeated here.

[0331] At step 509, if the target master base station or the candidate target master base station detects the problem is caused by the target secondary node (SN) or the candidate target SN, then the target master base station or the candidate target master base station sends a message to the target SN or the candidate target SN. For example, if a suitable PSCell is a candidate PSCell recommended / provided by the target master base station or the candidate target master base station, but not a candidate PSCell selected by the target SN or the candidate target SN, then the problem is caused by the target SN or the candidate target SN. The message may be an SCG failure information report. The information included in the message are the same as those in step 303 and will not be described in detail here. According to an embodiment of the disclosure, the target master base station or the candidate target master base station receives the UE identity from the source MN, and the target master base station may know the identity of the UE where the failure occurs, thereby sending a UE associated message to the target SN or the candidate target SN. The UE identity may be the MN UE AP ID allocated by the T-MN or the MN UE AP ID allocated by the source MN or other UE identity.

[0332] Heretofore, the embodiment 2 of the method for supporting self-configuration self-optimization of the disclosure has been completed, by which robustness of mobility for conditional handover with secondary node can be supported, cause for failure can be correctly identified in case of failure by conditional handover or conditional handover with SCG or conditional handover with candidate SCG to make reasonable optimization, occurrence of failure can be avoided, continuity of service can be guaranteed, and labor cost for operators can be reduced.

[0333]

[0334] Figure 6 illustrates embodiment 3 of a method for supporting self-configuration self-optimization in the disclosure.

[0335] In Figure 6, an S-MN represents a source master node, an S-SN represents a source secondary node, a T(C)-MN represents a target (candidate) master node, and a T(C)-SN represents a target (candidate) secondary node. The method comprises the steps of:

[0336] At step 601, the handover procedure is completed. The handover procedure may be a conditional handover procedure involving a SN. The conditional handover involving the SN includes a conditional handover with an SN (e.g., there is at least one candidate SN) or a conditional handover procedure with at least one candidate SCG.

[0337] The target MN may send the candidate PSCell information list to the target SN via the SN status transfer message. The candidate PSCell information includes candidate PSCell identities and execution conditions for each PSCell.

[0338] The target SN or the candidate SN may send mobility information in the target PSCell or the candidate target PSCell to the target MN or the candidate MN. The target SN or the candidate SN may send the mobility information in the target PSCell or candidate target PSCell to the target MN or the candidate MN via an SN addition request acknowledge message or other message.

[0339] At step 602, a MCG failure occurs. The MCG failure occurs in a cell in the target MN. The cell is the target cell of the last handover. The UE saves information of an RLF.

[0340] At step 603, a SCG failure occurs. The UE saves information on an SCG failure. This step is an optional step.

[0341] The UE saving the information on the failure is the same as that in step 301, and will not be repeated here.

[0342] Step 604 to step 605are the same as step 504 to step 505, and will not be repeated here.

[0343] At step 606, the RAN node that receives the information on the failure from the UE sends a message to the RAN node serving the UE when or before the failure occurs, e.g., for a failure occurring after the handover completion, the RAN node serving the UE when or before the failure occurs is the target MN, and the RAN node that receives the information on the failure from the UE sends a message to the target MN, the UE failure information includes RLF Report and / or SCG failure information. Both the RLF Report and the SCG failure message can be sent in this way. The message contains the information on the failure received from the UE. This step is an optional step. If the source MN receives a UE information response from the UE, the source MN sends the information on the failure received from the UE to the RAN node serving the UE when or before the failure occurs. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node may send the RLF Report and the information on the SCG failure to the RAN node serving the UE at the time of the failure or prior to the failure through two messages, respectively. The method for associating the RLF Report with the information on the SCG failure by the RAN node serving the UE at the time of the failure or prior to the failure is the same as that described in step 301, and will not be repeatedly described here. If the RAN node receives the RLF Report and the information on the SCG failure from the UE through different messages, the RAN node that receives the failure information from the UE can also send the RLF Report and the information on the SCG failure to the master base station last serving the UE through one message. In this case, the RAN node that receives the failure information from the UE needs to associate the RLF Report with the information on the failure SCG, and the specific associating method is the same as that in step 301, which is not repeated here.

[0344] For the way that the UE saves the RLF Report and the SCG failure information separately, the RLF Report and the information on the SCG failure information can also be sent to the different RAN nodes, for example, , for the failure after completing the handover, the RAN node serving the UE at the time of the failure or prior to the failure is the target MN, the RAN node receiving the RLF Report from the UE sends a message to the target MN, and the RAN node receiving the SCG failure information from the UE sends a message to the target MN or the source MN.

[0345] The message may be an RLF indication message, an HO report message, an access and mobility indication message, or other messages. The information contained in the message is the same as that described in step 303, and will not be repeated here.

[0346] At step 607, the RAN node serving the UE when or before the failure occurs detects the cause of the failure or the type of the failure. The specific cause or type of the failure and the method of detection are the same as those described in step 303, and will not be repeated here.

[0347] At step 608, if it is detected that the problem is caused by the source base station, the RAN node serving the UE when or before the failure occurs sends a message to the source base station. The message may be an RLF indication message, an HO report message, access and mobility indication message or other message. The message contains the same information as described in step 303 and will not be repeated here.

[0348] At step 609, according to an embodiment of the disclosure, the RAN node serving the UE when or before the failure occurs may be the target master base station. If the target master base station detects that the problem is caused by a target secondary node (SN) or a candidate target SN, the target master base station sends a message to the target SN or candidate target SN. For example, if a suitable PSCell is a candidate PSCell recommended / provided by the target master base station, but not a candidate PSCell selected by the target SN or candidate SN, then the a problem is caused by the target SN or candidate SN. The message may be an SCG failure information report. The information included in the message are the same as the information in step 303 and will not be described in detail here.

[0349] Heretofore, the embodiment 3 of the method for supporting self-configuration self-optimization of the disclosure has been completed, by which the mobility robustness of a conditional handover with a secondary node can be supported, the cause of the failure can be correctly identified in case of a failure caused by a conditional handover or a conditional handover with a SCG or a conditional handover with a candidate SCG, so as to make reasonable optimization, avoid occurrence of a failure, guarantee continuity of a service, and reduce a labor cost of an operator.

[0350]

[0351] Figure 7 illustrates embodiment 4 of a method for supporting self-configuration self-optimization in the disclosure.

[0352] In Figure 7, an S-MN represents a source master node, an S-SN represents a source secondary node, a T(C)-MN represents a target (candidate) master node, and a T(C)-SN represents a target (candidate) secondary node. The method comprises the steps of:

[0353] Step 700is the same as step 601, and will not be repeated here.

[0354] At step 701, an SCG failure occurs. A UE saves information on the SCG failure. The UE saving the information on the failure is the same as in step 301, and will not be repeated here.

[0355] At step 702, the UE transmits SCG failure information to the target master base station, and the content comprised in the SCG failure information is the same as that described in step 301, and will not be repeatedly described here. The target master base station is a master base station serving the UE when the SCG failure occurs.

[0356] The target master base station detects the cause of the failure.

[0357] At step 702a, if the problem is caused by the target SN, for example, if the suitable PSCell is a candidate PSCell recommended by the target master base station, but not a candidate PSCell selected by the target SN, the problem is caused by the target SN, and the target master base station sends a message to the target SN, and the message may be an SCG failure information report. The information contained in the message is the same as that in step 303, and will not be repeated here.

[0358] At step 703, an MCG fails. The UE saves information on an RLF. The UE saving information on the failure is the same as in step 301, and will not be repeated here. The MCG failure occurred in a cell of the target MN. The cell is the target cell of the last handover.

[0359]

[0360] Steps 704 to 708are the same as steps 604 to 608, and will not be repeated here.

[0361] Heretofore, the embodiment 4 of the method for supporting self-configuration self-optimization of the disclosure has been completed, by which the mobility robustness of a conditional handover with a secondary node can be supported, the cause of the failure can be correctly identified in case of a failure caused by a conditional handover or a conditional handover with a SCG or a conditional handover with a candidate SCG, so as to make reasonable optimization, avoid occurrence of a failure, guarantee continuity of a service, and reduce a labor cost of an operator.

[0362]

[0363] Figure 8 illustrates embodiment 5 of a method for supporting self-configuration self-optimization in the disclosure.

[0364] In Figure 8, an S-MN represents a source master node, an S-SN represents a source secondary node, a T(C)-MN represents a target (candidate) master node, and a T(C)-SN represents a target (candidate) secondary node. The method comprises the steps of:

[0365] At step 800, a UE receives configuration information of CHO with candidate SCG(s).

[0366] At step 801, an SCG failure occurs. The UE saves information on the SCG failure. The UE saving the information on the failure is the same as in step 301, and will not be repeated here.

[0367] At step 802, the UE transmits the SCG failure information to the master base station serving the UE. In the present embodiment, the source master base station is a master base station serving the UE. The content included in the SCG failure information is the same as that described in step 301, and will not be repeatedly described here.

[0368] In the method of the present invention, the source master base station receiving the SCG failure information can detect the cause of the failure or the target master base station can detect the cause of the failure. The specific detection method is the same as that in step 303, and will not be described here. Corresponding to the method of detection by the source master base station, if it is detected that the problem is caused by the target master base station or the candidate target master base station, the source master base station sends a message to the target master base station or the candidate target master base station, and the specific information comprised in the message is the same as those in step 303, so the details are not repeated here. Step 802a is executed corresponding to the method of detection by the target master base station.

[0369] At step 802a, the source master base station transmits a failure information indication to the target master base station. The failure information indication includes the SCG failure information received from the UE. The specific information comprised in the failure information indication is the same as those in step 303, and will not be repeated here. The failure indication information may be an RLF indication message or another message.

[0370] The target master base station detects the cause of the SCG failure occurring. The detection method is the same as that in step 303, and will not be repeated here.

[0371] At step 802b, if the problem is caused by the target SN, for example, if the suitable PSCell is a candidate PSCell recommended by the target master base station but not a candidate PSCell selected by the target SN, the problem is caused by the target SN, and the target master base station sends a message to the target SN, and the message may be an SCG failure information report. The information contained in the message is the same as that in step 303, and will not be repeated here.

[0372] At step 803, an MCG failure occurs. The UE saves information on an RLF. The UE saving the information on the failure is the same as that in step 301, and will not be repeated here.

[0373] Steps 804 to 807are the same as steps 504 to 507 and will not be repeatedly described herein

[0374] It should be noted that the target master base station receives the RLF Report from the UE at step 805, and the target master base station receives the SCG failure information at step 802a. The target master base station associates the RLF Report and the SCG failure information according to the method described in step 301, in order to determine that the RLF Report and the SCG failure information correspond to the same handover event. If the RLF Report and the SCG failure information correspond to the same handover event, the target master base station decides whether the suitable PSCell is the PSCell recommended by the target MN. If not, the SCG failure is caused by the unsuitable PSCell recommended by the target master base station, and the target master base station can optimize the selection of the PSCell.

[0375] Heretofore, the embodiment 5 of the method for supporting self-configuration self-optimization of the disclosure has been completed, by which the mobility robustness of a conditional handover with a secondary node can be supported, the cause of the failure can be correctly identified in case of a failure caused by a conditional handover or a conditional handover with a SCG or a conditional handover with a candidate SCG, so as to make reasonable optimization, avoid occurrence of a failure, guarantee continuity of a service, and reduce a labor cost of an operator.

[0376]

[0377] Figure 9 is a block diagram illustrating an exemplary structure of a network node in a network according to the disclosure.

[0378] The network nodes in the network may be used to implement the MN, the SN, the S-SN, the T-SN, other candidate T-SNs, etc. in the disclosure. Referring to Figure 9, a network node according to the disclosure comprises a transceiver 910, a controller 920 and a memory 9730. The transceiver 910, the controller 920, and the memory 930 are configured to perform the operations of the methods and / or embodiments of the disclosure. Although the transceiver 910, the controller 920, and the memory 930 are shown as separate entities, they may be implemented as a single entity, such as a single chip. The transceiver 910, the controller 920, and the memory 930 may be electrically connected or coupled to each other. The transceiver 910 may transmit and receive signals to and from other network nodes, such as UEs, MNs, SNs, S-SNs, T-SNs, other candidate T-SNs, or core network nodes. The controller 920 may include one or more processing units and may control the network node to perform operations and / or functions according to one of the above-described embodiments. The memory 930 may store instructions for implementing an operation and / or functionality of one of the embodiments described above.

[0379]

[0380] Figure 10 is a block diagram illustrating the structure of a user equipment UE according to an embodiment of the disclosure.

[0381] Referring to Figure 10, the UE according to the disclosure includes a transceiver 1010, a controller 1020, and a memory 1030. The transceiver 1010, the controller 1020, and the memory 1030 are configured to perform the operations of methods and / or embodiments of the disclosure. Although the transceiver 1010, controller 1020, and memory 1030 are shown as separate entities, they may be implemented as a single entity, such as a single chip. The transceiver 1010, the controller 1020, and the memory 1030 may be electrically connected or coupled to each other. The transceiver 1010 may transmit and receive signals to and from other network nodes, such as UEs, MNs, SNs, S-SNs, T-SNs, other candidate T-SNs, or core network nodes. The controller 1020 may include one or more processing units and may control the UE to perform an operation and / or function according to one of the above-described embodiments. The memory 1030 may store instructions for implementing operations and / or functionalities of one of the embodiments described above.

[0382] Those of skill in the art will appreciate that the above illustrative embodiments are described herein and are not intended to be limiting. It should be understood that any two or more of the embodiments disclosed herein may be combined in any combination. Further, other embodiments may be utilized, and other changes may be made, without departing from the spirit and scope of the subject matter presented herein. It will be readily understood that the aspects of the disclosure of the disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are contemplated herein.

[0383] Those skilled in the art will understand that the various illustrative logical blocks, modules, circuits, and steps described in this application may be implemented as hardware, software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in the form of their functional sets. Whether such function sets are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Technicians may implement the described functional sets in different ways for each specific application, but such design decisions should not be interpreted as causing a departure from the scope of this application.

[0384] The various illustrative logic blocks, modules, and circuits described in this application may be implemented or performed by a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic devices, discrete gates or transistor logics, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0385] The steps of the method or algorithm described in this application may be embodied directly in hardware, in a software module executed by a processor, or in a combination thereof. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor to enable the processor to read and write information from / to the storage media. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in the user terminal as discrete components.

[0386] In one or more exemplary designs, the functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, each function may be stored as one or more pieces of instructions or codes on a computer-readable medium or delivered through it. The computer-readable medium includes both a computer storage medium and a communication medium, the latter including any medium that facilitates the transfer of computer programs from one place to another. The storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.

[0387] In addition, the functions or operations described in the disclosure may be processed by a single processor or a combination of processors. The single processor or the combination of processors may include a circuit that performs processing, such as an application processor (AP, e.g., a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural network processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near-field communication (NFC) chip, a connectivity chip, a sensor controller, a touch controller, a fingerprint sensor controller, a display driver integrated circuit (IC), an audio codec (CODEC) chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, a microprocessor unit (MPU), a system on a chip (SoC), an IC, or a similar circuit.

[0388] In addition, it should be noted that various embodiments in the claims and description of the disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. Such software may be stored in a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium stores one or more computer programs (software modules), wherein the one or more computer programs, when executed alone or collectively by one or more processors of the electronic device, include computer-executable instructions that cause the electronic device to perform a method according to the disclosure. The software may be stored in a temporary or non-transitory storage device, and may be stored in, for example, a read-only memory (ROM) (whether erasable or rewritable), a random access memory (RAM), a memory chip, a device, or an integrated circuit (IC). In addition, the software may be stored in an optically or magnetically readable medium, such as a compact disc (CD), a digital versatile disc (DVD), a magnetic disk, or a magnetic tape. It should be understood that the storage device and the storage medium are examples of non-transitory machine-readable storage media suitable for storing programs for implementing various embodiments of the disclosure. Accordingly, various embodiments provide a program comprising code for implementing a device or method according to any one of the claims of the specification and a non-transitory machine-readable storage medium storing such program.

[0389] The above description is only an exemplary implementation of the disclosure, and is not intended to limit the scope of protection of the disclosure, which is determined by the appended claims.

Claims

1.A method performed by a terminal in a wireless communication system, the method comprising:receiving, from a source base station, configuration information for a conditional reconfiguration associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell);identifying a failure for an execution associated with the conditional reconfiguration, based on the configuration information;generating failure information based on a cause of the failure, the failure information including first information on whether a condition of the execution is fulfilled and second information on a time that the condition is fulfilled; andtransmitting, to a base station that a radio resource control (RRC) connection is established with the terminal, the failure information.2.The method of claim 1,wherein the conditional reconfiguration includes a conditional handover (CHO) and a conditional PSCell addition / change (CPAC) associated with the CHO.3.The method of claim 2,wherein the failure information further includes third information on a measurement result of the PCell and the PSCell,wherein the first information includes at least one of information indicating whether an execution condition for the CHO is fulfilled for the PCell, information indicating whether an execution condition for the CPAC is fulfilled for the PSCell, identification information of the PCell, and identification information of the PSCell, andwherein the second information includes at least one of information indicating a first-fulfilled condition between the execution condition for the CHO and the execution condition for the CPAC, information on a time gap between the first-fulfilled condition and a second-fulfilled condition, and information on a time gap between the first-fulfilled condition and the failure.4.The method of claim 2,wherein the cause of the failure is identified as a too late handover, in case that an execution condition for the CHO is fulfilled after an execution condition for the CPAC is fulfilled,wherein the base station is a target base station,wherein the failure information is forwarded to the source base station via the base station, andwherein the failure information being included in a handover report message transmitted from the target base station to the source base station.5.A method performed by a base station in a wireless communication system, the method comprising:obtaining failure information for a terminal, the failure information including first information on whether a condition of an execution associated with a conditional reconfiguration is fulfilled and second information on a time that the condition is fulfilled, wherein the conditional reconfiguration is associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell); anddetermining a cause of a failure for the execution for optimization, based on the failure information.6.The method of claim 5,wherein the conditional reconfiguration includes a conditional handover (CHO) and a conditional PSCell addition / change (CPAC) associated with the CHO, andwherein the failure information is obtained from the terminal where a radio resource control (RRC) connection is established with the base station.7.The method of claim 6,wherein the failure information further includes third information on a measurement result of the PCell and the PSCell,wherein the first information includes at least one of information indicating whether an execution condition for the CHO is fulfilled for the PCell, information indicating whether an execution condition for the CPAC is fulfilled for the PSCell, identification information of the PCell, and identification information of the PSCell, andwherein the second information includes at least one of information indicating a first-fulfilled condition between the execution condition for the CHO and the execution condition for the CPAC, information on a time gap between the first-fulfilled condition and a second-fulfilled condition, and information on a time gap between the first-fulfilled condition and the failure.8.The method of claim 6, further comprising:in case that an execution condition for the CHO is fulfilled after an execution condition for the CPAC is fulfilled, transmitting, to a source base station, a handover report message including the failure information,wherein the cause of the failure is determined as a too late handover,wherein the optimization is associated with the source base station, andwherein the base station is a target base station.9.A terminal in a wireless communication system, the terminal comprising:a transceiver; anda processor coupled with the transceiver and configured to:receive, from a source base station, configuration information for a conditional reconfiguration associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell),identify a failure for an execution associated with the conditional reconfiguration, based on the configuration information,generate failure information based on a cause of the failure, the failure information including first information on whether a condition of the execution is fulfilled and second information on a time that the condition is fulfilled, andtransmit, to a base station that a radio resource control (RRC) connection is established with the terminal, the failure information.10.The terminal of claim 9,wherein the conditional reconfiguration includes a conditional handover (CHO) and a conditional PSCell addition / change (CPAC) associated with the CHO.11.The terminal of claim 10,wherein the failure information further includes third information on a measurement result of the PCell and the PSCell,wherein the first information includes at least one of information indicating whether an execution condition for the CHO is fulfilled for the PCell, information indicating whether an execution condition for the CPAC is fulfilled for the PSCell, identification information of the PCell, and identification information of the PSCell, andwherein the second information includes at least one of information indicating a first-fulfilled condition between the execution condition for the CHO and the execution condition for the CPAC, information on a time gap between the first-fulfilled condition and a second-fulfilled condition, and information on a time gap between the first-fulfilled condition and the failure.12.The terminal of claim 10,wherein the cause of the failure is identified as a too late handover, in case that an execution condition for the CHO is fulfilled after an execution condition for the CPAC is fulfilled,wherein the base station is a target base station,wherein the failure information is forwarded to the source base station via the base station, andwherein the failure information being included in a handover report message transmitted from the target base station to the source base station.13.A base station in a wireless communication system, the base station comprising:a transceiver; anda processor coupled with the transceiver and configured to:obtain failure information for a terminal, the failure information including first information on whether a condition of an execution associated with a conditional reconfiguration is fulfilled and second information on a time that the condition is fulfilled, wherein the conditional reconfiguration is associated with at least one of a primary cell (PCell) and a primary secondary cell (PSCell), anddetermine a cause of a failure for the execution for optimization, based on the failure information.14.The base station of claim 13,wherein the conditional reconfiguration includes a conditional handover (CHO) and a conditional PSCell addition / change (CPAC) associated with the CHO,wherein the failure information is obtained from the terminal where a radio resource control (RRC) connection is established with the base station,wherein the failure information further includes third information on a measurement result of the PCell and the PSCell,wherein the first information includes at least one of information indicating whether an execution condition for the CHO is fulfilled for the PCell, information indicating whether an execution condition for the CPAC is fulfilled for the PSCell, identification information of the PCell, and identification information of the PSCell, andwherein the second information includes at least one of information indicating a first-fulfilled condition between the execution condition for the CHO and the execution condition for the CPAC, information on a time gap between the first-fulfilled condition and a second-fulfilled condition, and information on a time gap between the first-fulfilled condition and the failure.15.The base station of claim 14,wherein the processor is further configured to transmit, to a source base station, a handover report message including the failure information, in case that an execution condition for the CHO is fulfilled after an execution condition for the CPAC is fulfilled,wherein the cause of the failure is determined as a too late handover,wherein the optimization is associated with the source base station, andwherein the base station is a target base station.

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