Method and user equipment for logging mobility history information

Abstract

The disclosure provides a method and a User Equipment for logging mobility history information by a user equipment operating in a wireless communication system. The method includes detecting, by a user equipment (UE), a mobility event associated with a Primary Cell (PCell) or a Primary Secondary Cell Group Cell (PSCell). The method includes determining, by the UE in response to the detected mobility event, an activation duration representing time spent by the UE in the PSCell with the SCG activated. The method includes logging, by the UE in response to the detected mobility event, the time spent by the UE in the PSCell with the SCG activated, in Mobility History Information (MHI).

Description

METHOD AND USER EQUIPMENT FOR LOGGING MOBILITY HISTORY INFORMATION

[0001] The disclosure relates generally to wireless communication systems, and more particularly to method and user equipment for logging mobility history information.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz 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.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive 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.

[0004] Currently, 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 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, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, 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, 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 procedure (2-step 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 UE positions.

[0006] As 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 is 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.

[0007] Furthermore, 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 UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] The disclosure overcomes one or more shortcomings of the prior art and provides additional advantages discussed throughout the disclosure. Additional features and advantages are realized through the techniques of the disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

[0009] In an aspect, the disclosure provides method for logging mobility history information by a user equipment operating in a wireless communication system. The proposed method involves detecting by a user equipment (UE) a mobility event associated with a Primary Cell (PCell) or a Primary Secondary Cell Group Cell (PSCell). Determining in response to the detected mobility event, an activation duration representing time spent by the UE in the PSCell with the SCG activated and logging, by the UE in response to the detected mobility event, the time spent by the UE in the PSCell with the SCG activated, in Mobility History Information (MHI).

[0010] In an embodiment, detecting the mobility event comprises detecting one of change of the PSCell or release of the PSCell.

[0011] In an embodiment, the method further involves identifying, the time spent by the UE in the PSCell with the SCG activated, exceeds a predefined threshold value and logging, the predefined threshold value as the time spent by the UE in the PSCell with the SCG activated based on the identifying.

[0012] In an embodiment, the mobility event comprises change, or release of a PSCell while being connected to the current PCell, or release of a PSCell while entering 'camped normally' state in the same serving cell which was previously the PCell.

[0013] In an embodiment, the mobility event comprises PSCell release while entering 'any cell selection' state or 'camped on any cell' state from a suitable cell in RRC_CONNECTED state in NR or LTE, or the PSCell release while entering 'camped normally' state while previously in RRC_CONNECTED state in a PCell different from the current serving cell.

[0014] In an embodiment, method further involves storing time spent with SCG activated in a visitedPSCellInfoList of the MHI and reporting the visitedPSCellInfoList in a VarMobilityHistoryReport to a network entity (110).

[0015] In an embodiment, the mobility event involves change of suitable cell, including PCell or serving cell, to another cell, or when entering 'any cell selection' state from 'camped normally' state or when entering 'any cell selection' state or 'camped on any cell' state from a suitable cell and the UE performs one of: continues to be connected to the same PSCell during the change of the PCell, changes PSCell at the same time as the change of the PCell or release the PSCell at the same time as the change of the PCell.

[0016] In an aspect, the disclosure provides user equipment (UE) for logging mobility history information in a wireless communication system. The UE includes a processor and a memory storing instructions which, when executed by the processor to detect a mobility event associated with a Primary Cell (PCell) or a Primary Secondary Cell Group Cell (PSCell), determine in response to the detected mobility event, an activation duration representing time spent by the UE in the PSCell with the SCG activated and log in response to the detected mobility event, the time spent by the UE in the PSCell with the SCG activated, in Mobility History Information (MHI).

[0017] In another aspect, the disclosure provides wireless communication system including a user equipment (UE) configured to log Mobility History Information including a value representing time spent by the UE in a Primary Secondary Cell Group Cell (PSCell) with a Secondary Cell Group activated and a network entity configured to receive the Mobility History Information from the user equipment.

[0018] In an embodiment, value representing the time spent by the UE in the PSCell with the Secondary Cell Group activated is reported in units of seconds within a predefined representable range from zero to a maximum value N, and when an actual time spent by the UE in the PSCell with the Secondary Cell Group activated exceeds the maximum value N, the UE stores and reports the maximum value N in the Mobility History Information

[0019] In an embodiment, the maximum value N equals four thousand ninety-five seconds.

[0020] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

[0021] The embodiments of the disclosure itself, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings in which:

[0022] Fig. 1 illustrates an exemplary system environment in which embodiments of the disclosure may be practiced, in accordance with some embodiments of the disclosure.

[0023] FIG. 2 illustrates the User Equipment (UE) for logging mobility history information, in accordance with an embodiment of the disclosure

[0024] FIG. 3 illustrates a flow diagram of a method for logging mobility history information, in accordance with an embodiment of the disclosure.

[0025] FIG. 4 illustrates a sequence flow of a method for logging mobility history information by a user equipment (UE) and reporting a network entity, in accordance with some embodiments of the disclosure.

[0026] Fig. 5 illustrates a block diagram of an exemplary computer system, in accordance with some embodiments of the disclosure.

[0027] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0028] In describing the embodiments, while numerous details are set forth for the purpose of illustration, it is understood that some aspects of the disclosure may be practiced with less than all of these details. Numerous variations and alternatives to the details provided herein are possible and are considered within the scope of the disclosure. In some instances, descriptions related to technical contents well-known in the art may be omitted so as to not obscure an understanding of the disclosure, and such omitted descriptions are understood to be within the scope of the disclosure.

[0029] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Further, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals or different reference numerals.

[0030] The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described herein in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth herein, but may be implemented in various different forms. Other features, aspects, and advantages of the subject matter described herein will become apparent from the disclosure. The following embodiments are merely examples to aid in an understanding of the disclosure and should not be construed to narrow the scope or spirit of the subject matter described herein in any way, but on the contrary, the disclosure covers all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims and equivalents thereof. Throughout the specification, the same or like reference numerals designate the same or like elements. Furthermore, terms which will be described herein are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the operators, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

[0031] Herein, it will be understood that each block of flowchart illustrations, and combinations of blocks in the flowchart illustrations, may be performed based on computer program instructions. These computer program instructions may be loaded collectively onto at least one processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which perform through any one of, or in any combination of, the at least one processor of the computer or other programmable data processing apparatus, create means for performing the functions specified in the flowchart block(s). These computer program instructions may also be stored in a non-transitory computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that perform the function specified in the flowchart block(s). The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable data processing apparatus to produce a computer executed process such that the instructions that perform on the computer or other programmable data processing apparatus provide steps for executing the functions specified in the flowchart block(s).

[0032] Further, each block may represent a module, segment, or portion of code, which includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks(or functions) shown in succession may in fact be performed substantially concurrently or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved.

[0033] As used in embodiments of the disclosure, a "~unit / module" may refer to a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), which performs a predetermined function. However, the term including the word "~unit / module" does not always have a meaning limited to software or hardware. The "~unit / module" may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the "~unit / module" includes, for example, software elements, object-oriented software elements, components such as class elements and task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The components and functions provided by the "~unit / module" may be either combined into a smaller number of components and a "~unit / module," or divided into additional components and a "~unit / module." Moreover, the components and "~units / modules" may be implemented to reproduce one or more central processing units (CPUs) within a device or a security multimedia card. Further, in the embodiments, the "~unit / module" may include one or more processors.

[0034] The entirety of the one or more computer programs may be stored in a single memory device or the one or more computer programs may be divided with different portions stored in different multiple memory devices.

[0035] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP, e.g. a CPU), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural 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, connectivity chips, a sensor controller, a touch controller, a finger-print sensor controller, a display driver integrated circuit (IC), an audio CODEC chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, microprocessors, microcontrollers, digital　signal processors, FPGA, ASIC, a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like. The one processor or the combination of processors executes instructions that can be stored in a memory, such as the　operating system, in order to control the overall operation of the device.　Also, the one processor or the combination of processors is also capable of executing other processes and programs　resident in the memory, such as processes for the disclosure.

[0036] It will be appreciated that various embodiments of the disclosure according to the claims and description in the specification can be realized in the form of hardware, software or a combination of hardware and software.

[0037] Any such software may be stored in non-transitory computer readable storage media. The non-transitory computer readable storage media store one or more computer programs (software modules), the one or more computer programs include computer-executable instructions that, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure. Additionally, or alternatively, such software may be a computer program [product] comprising instructions which, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure.

[0038] Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like read only memory (ROM), whether erasable or rewritable or not, or in the form of memory such as, for example, random access memory (RAM), memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a compact disk (CD), digital versatile disc (DVD), magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are various embodiments of non-transitory machine-readable storage that are suitable for storing a computer program or computer programs comprising instructions that, when executed, implement various embodiments of the disclosure. Accordingly, various embodiments of the disclosure may provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a non-transitory machine-readable storage storing such a program.

[0039] Hereinafter, the determination of priority between A and B in the disclosure may refer to various actions such as selecting the one having a higher priority based on a predefined priority rule and performing an operation corresponding thereto, or omitting or dropping an operation corresponding to the one having a lower priority.

[0040] Hereinafter, "A or B" as described in the disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0041] In addition, "at least one of A, B, and C" as described in the disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0042] In addition, "at least one of A, B, or C" as described in the disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0043] Furthermore, "A / B" as described in the disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0044] Furthermore, "A, B" as described in the disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0045] Furthermore, "A and B" as described in the disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0046] Furthermore, "if condition A and condition B are satisfied," as described in the disclosure, may not be limited to a case where both condition A and condition B are satisfied, but may be understood to include a case where either condition A or condition B is individually satisfied, both condition A and condition B are satisfied, or one or more additional conditions are satisfied in combination.

[0047] Furthermore, throughout this disclosure, ordinal terms such as "first," "second," "third," etc., (and similar qualifiers) are used merely to distinguish between different instances, occurrences, configurations, messages, stages, elements or aspects of elements, operations, or information as described herein. Unless the context clearly dictates otherwise, the use of such ordinal terms does not itself require that the elements, operations, or information distinguished by these terms be structurally different, numerically distinct, or substantively dissimilar. For example, a "first signal" and a "second signal" may refer to instances of the same signal transmitted at different times or containing the same core information despite minor variations, or they may refer to signals with different content or characteristics, depending on the specific context. Similarly, a "first value" and a "second value" may represent the same magnitude but measured or applied in different circumstances, or they may represent different magnitudes. The interpretation should be guided by the specific technical context, function, and relationship described in the relevant portion of the specification and claims.

[0048] Furthermore, the terms "first ~", "second ~", etc., as described in the disclosure with respect to various elements (e.g., information, objects, operation, sequences, or the like), should not limit those elements. These terms may only be intended to distinguish one element from another, and may not be intended to indicate a specific order. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element.

[0049] Furthermore, even if "first ~" and "second ~" are described in the disclosure, it may be understood that element(s) referred to by "first ~" and "second ~" may be the same or different. For example, in case of element(s) being information, first information and second information may both be same information and, in some cases, are separate and different information.

[0050] In addition, the terms "if ~" and "in case that ~" as used in the disclosure or claims may be interpreted to include the meanings of "when (or upon) ~," "in response to ~," "based on ~," or "according to ~," and may be used interchangeably with these expressions. In addition, expressions other than those exemplified herein may also be used, as long as they have substantially the same meaning and do not impair the technical features of the disclosure. If a method step (e.g. transmit a signal) is performed according to the disclosure of the application in connection with one of the above terms (such as "in case that ~" or the like), it may be interpreted to include the meanings (disclosure) of a prior determination that a feature has a specific state "~" (e.g. a bit length is above X), and then perform the method step in response to said determination.

[0051] For example, the physical layer signaling may be referred to as Layer 1 (L1) signaling and may include downlink control information (DCI). In addition, the higher layer signaling may include a medium access control (MAC) control message, a radio resource control (RRC) signaling message, a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as L3 (layer 3) signaling. It should be noted, however, that the higher layer signaling is not limited to the aforementioned examples.

[0052] In addition, the term "not perform" as used in the disclosure or claims may, in context, be understood to mean that the corresponding step is omitted or skipped. Such a term may be replaced with other terms having the same or substantially equivalent meaning.

[0053] In addition, "transmitting a message including A and B" as described in the disclosure, may be understood as encompassing both (i) transmitting A and B in a single message, and (ii) transmitting A and B separately via multiple messages (e.g., transmitting a first message including A and a second message including B). This interpretation may also apply to messages that include two or more items (e.g., A, B, C), transmitted either together or separately.

[0054] In addition, "transmitting a message including A and transmitting a message including B" may also be interpreted as transmitting a message including A and B in a single message.

[0055] In the embodiments of the disclosure described herein, terms or components included in the disclosure may be expressed in singular or plural form depending on the specific embodiments presented. However, such singular or plural expressions are selected appropriately for convenience of description, and the disclosure is not limited to a singular or plural number of components. A component expressed in the plural form may be implemented as a single component, and a component expressed in the singular form may be implemented as multiple components.

[0056] The drawings or flowcharts described herein illustrate example methods that may be implemented according to the principles of the disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the disclosure. For example, although illustrated as a series of steps, various steps in each drawing or flowchart may overlap, occur in parallel, occur in a different order, or be repeated. In other examples, any step may be omitted or replaced with another step.

[0057] The process of the flowchart may be performed by a device. One or more of the steps of the　flowchart can be implemented by one or more processors / computer programs executing　instructions to perform the noted functions.

[0058] The methods and apparatuses proposed in the embodiments of the disclosure may be disclosed in connection with drawings disclosing flowcharts to illustrate example methods that may be implemented according to the principles of the disclosure. Such flowcharts may contain different branches and / or sub-branches. It is understood that the principles of the disclosure do not only contain the combination of all branches / sub-branches disclosed in the embodiment, but the disclosure also contains at least one isolated branch / isolated sub-branch, in particular to a single branch / single sub-branch.

[0059] The methods and apparatuses proposed in the embodiments of the disclosure are not limited to each embodiment individually, but may also be applied in combination of all or some of the embodiments proposed in the disclosure. Therefore, the embodiments of the disclosure may be modified and applied without significantly departing from the scope of the disclosure, as would be understood by those skilled in the art.

[0060] In this case, even if certain wordings are described differently across embodiments, they may be used interchangeably or in substitution or in combination if their underlying concepts are equivalent. For example, for the same or equivalent concept, even if one embodiment uses the expression "A" and another embodiment uses the expression "B", such expressions may be understood interchangeably, in substitution, or in combination.

[0061] The terms used in the following description to refer to access nodes, network entities, messages, interfaces between network entities, various types of identification information, and the like, are provided merely for the convenience of explanation by way of example. Therefore, the disclosure is not limited to the terms described herein, and other terms having equivalent technical meanings may also be used. Such terms may also be interchangeable with terms defined in any 3rd generation partnership project　(3GPP) technical specifications (TS) or similar technical specifications, e.g., from the European telecommunications standards institute (ETSI), where appropriate.

[0062] Hereinafter, a base station (BS) is an entity that allocates resources to terminals, and may be at least one of a gNode B, an eNode B, a Node B, a wireless access unit, a BS controller, or a node on a network.

[0063] Furthermore, the base station of the disclosure may include a split architecture comprising a central unit (CU) and a distributed unit (DU). In this structure, the CU is configured to process the higher layers of the control and user planes, while the DU is configured to process lower-layer radio resource functions. The embodiments of the disclosure may be equally applicable to 5th generation (5G) base station architectures in which such CU and DU functional splits are implemented.

[0064] A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, a tablet, a wearable device, an Internet of Things (IoT) device, or any other device / system capable of performing communication functions.

[0065] In the disclosure, a downlink (DL) refers to a radio link through which a BS transmits a signal to a terminal, and an uplink (UL) refers to a radio link through which a terminal transmits a signal to a BS.

[0066] Furthermore, hereinafter, 5G mobile communication technologies (e.g., 5G new radio (NR)), 6th generation (6G) mobile communication technologies may be described by way of example, but the embodiments of the disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, newly evolved mobile communication systems developed after 5G and 6G may be included. Furthermore, based on determinations by those skilled in the art, the embodiments of the disclosure may also be applied to other communication systems (e.g., Wi-Fi systems) through some modifications without significantly departing from the scope of the disclosure

[0067] In the following description, the terms physical channel and signal may be used interchangeably with data or control signal. For example, the term physical downlink shared channel (PDSCH) refers to a physical channel through which data is transmitted, but the term PDSCH may also be used to refer to the data itself. That is, in the disclosure, the expression "transmit a physical channel" may be interpreted as being equivalent to the expression "transmit data or a signal via a physical channel."

[0068] Hereinafter, in the context of the disclosure, higher layer signaling may refer to signaling corresponding to at least one or any combination of the following: master information block (MIB), system information block (SIB) or SIB M (M = 1, 2, ...), RRC, or MAC control element (CE), or a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as Layer 3 (L3) signaling.

[0069] In addition, L1 signaling may refer to signaling corresponding to at least one or any combination of signaling techniques using the at least one or any combination of the following physical layer channels or signaling: physical downlink control channel (PDCCH), DCI, UE-specific DCI, group-common DCI, common DCI, scheduling DCI (e.g., DCI used for scheduling downlink or uplink data), non-scheduling DCI (e.g., DCI not used for scheduling downlink or uplink data) physical uplink control channel (PUCCH), or uplink control information (UCI). The L1 signaling message may be referred to as a physical layer signaling.

[0070] Hereinafter, the expression that information is configured by the BS, as used in the disclosure or claims, may, in context, be understood to mean that the terminal receives the corresponding information from the BS via a physical layer signaling or a higher layer signaling. Such an expression may be replaced with other terms having the same or substantially equivalent meaning.

[0071] Hereinafter, the operational principle of the disclosure will be described in detail with reference to the accompanying drawings.

[0072]

[0073] Modern wireless communication networks support a wide range of services and deployment scenarios that require efficient use of radio resources and reliable mobility management. To meet increasing performance demands, network architectures have evolved to support advanced connectivity modes in which a user equipment may be served by multiple cells simultaneously.

[0074] Dual connectivity is one such connectivity mode in which a user equipment may connect with a PCell of a master / primary node and a PSCell of a secondary node. This architecture enables improved throughput, coverage, and load balancing by allowing the user equipment to utilize resources from multiple network nodes.

[0075] During operation in a dual connectivity environment, the configuration and utilization of secondary cell group cells may vary over time based on factors such as traffic demand, radio conditions, mobility, and network policies. As the user equipment moves within the network or experiences changes in connectivity, various mobility-related events may occur, including cell additions, cell changes, cell releases, and transitions between different operational states.

[0076] Wireless communication systems commonly maintain historical information related to cell usage and mobility behaviour of user equipment. Such historical information may be logged and reported by the UE to support network management, performance optimization, coverage analysis, and other operational or analytical functions. The logging and reporting of mobility-related historical information in complex connectivity scenarios, such as those involving multiple cell groups, present challenges in ensuring that the recorded information accurately reflects past network conditions and usage patterns. In particular, the dynamic nature of multi-cell group configurations and mobility events can complicate the interpretation and usefulness of stored historical data.

[0077] Additionally, user equipment implementations are subject to practical constraints related to memory capacity, processing capability, and signalling overhead. These constraints may limit the granularity or range of information that can be stored or reported while maintaining efficient operation and compliance with system requirements.

[0078] Accordingly, there is a need to manage how mobility-related historical information is collected, stored, and reported in wireless communication systems that support advanced connectivity modes, in a manner that balances informational value with implementation complexity and resource constraints.

[0079] The information disclosed in the background section is provided solely to assist in understanding the general technical context of the disclosure and should not be construed as an admission that any of the described material constitutes prior art known to a person skilled in the art.

[0080]

[0081] The multi-radio dual connectivity (MR-DC) in mobile communication networks, is specified in 3GPP standards such as TS 37.340. MR-DC enables a user equipment (UE) in RRC_CONNECTED state to utilize radio resources from two distinct schedulers located in different NG-RAN nodes. The nodes are connected via a non-ideal backhaul, with one providing NR (New Radio) access and another providing either E-UTRA (Evolved UMTS Terrestrial Radio Access) or NR access. One of the nodes serves as a Master Node (MN) while the other serves as a Secondary Node (SN), with the MN connected to the core network.

[0082] The configuration allows various forms of dual connectivity, including NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC) and NR-E-UTRA Dual Connectivity (NE-DC), supporting seamless communication and improved data rates for the UE. NG-RAN supports NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), in which the UE is connected to one ng-eNB (a E-UTRA base station that can connect to 5G core) that acts as a MN and one gNB (5G base station) that acts as a SN. NG-RAN also supports NR-E-UTRA Dual Connectivity (NE-DC), in which a UE is connected to one gNB that acts as a MN and one ng-eNB that acts as a SN

[0083] In MR-DC, key concepts include the Master Cell Group (MCG) and Secondary Cell Group (SCG), where the MCG consists of cells associated with the MN, and the SCG consists of cells associated with the SN. The cell groups include primary and secondary serving cells (SpCell and PSCell) that ensure efficient data transmission and management of connectivity. The process for Secondary Node Addition and PSCell Addition involves coordination between the MN and SN, with specific conditions triggering the Conditional PSCell Addition (CPA) by the UE.

[0084] The Secondary Node Addition procedure is initiated by the MN and is used to establish a UE context at the SN to provide resources from the SN to the UE. PSCell Addition takes place during SN Addition procedure. A Conditional PSCell Addition (CPA) is defined as a PSCell addition that is executed by the UE when execution condition(s) is met. The UE starts evaluating the execution condition(s) upon receiving the CPA configuration and stops evaluating the execution condition(s) once PSCell addition or PCell change is triggered.

[0085] Therefore, there is a need to improve the existing frameworks defined by 3GPP for improving the performance, reliability, and efficiency of dual connectivity operations in modern 5G networks, addressing challenges related to multi-cell coordination, resource allocation, and mobility management. Particularly, there is a need for method and system to report information about the time SCG was activated in mobility history information (MHI).

[0086] In an embodiment, UE informs the network entity whether it is capable of supporting enhancements for reporting the SCG activation and deactivation related information in Mobility history information (MHI). UE informs the network entity whether UE supports storage of information related to SCG activation and deactivation in MHI and reports the information via UEInformationResponse. The information related to SCG activation and deactivation in MHI may be:

[0087] - 　duration when the SCG is activated for a PSCell in a PCell or the percentage of time when the SCG is activated for a PSCell in a PCell out of the total time the PSCell was configured,

[0088] - 　duration when the SCG is deactivated for a PSCell in a PCell or the percentage of time when the SCG was deactivated for a PSCell in a PCell out of the total time the PSCell was configured.

[0089] In NR, the capability information related to SCG activation and deactivation in MHI may be reported as per UE capability without Frequency Division Duplex - Time Division Duplex (FDD-TDD) difference or frequency range (FR) difference (i.e. FR1-FR2 difference).

[0090] In an embodiment, the network entity may configure the UE to store and report the information related to the SCG activation and deactivation. The network entity may configure the UE to store and report the time related information about SCG activation and deactivation. The time-related information may include:

[0091] - 　duration when the SCG is activated for a PSCell in a PCell or the percentage of time when the SCG is activated for a PSCell in a PCell out of the total time the PSCell was configured,

[0092] - 　duration when the SCG deactivated for a PSCell in a PCell or the percentage of time when the SCG was deactivated for a PSCell in a PCell out of the total time the PSCell was configured and the like.

[0093] In an embodiment, if the network entity has configured the UE to store and report the information related to the SCG activation and deactivation, UE may log (In the context of the disclosure "log" is used as synonymous to "store and report". Reporting is typically based on the request by the network as defined in 3GPP TS such as TS 38.331) the information related to the SCG activation and deactivation. In an embodiment, this may be time related information about SCG activation and deactivation such as:

[0094] - 　duration when the SCG is activated for a PSCell in a PCell or the percentage of time when the SCG is activated for a PSCell in a PCell out of the total time the PSCell was configured,

[0095] - 　duration when the SCG deactivated for a PSCell in a PCell or the percentage of time when the SCG was deactivated for a PSCell in a PCell out of the total time the PSCell was configured and the like.

[0096] In an embodiment, if the network entity has configured the UE to store and report the information related to the SCG activation and deactivation, the UE may log the duration of stay in the PSCell with SCG activated instead of logging the duration of stay in the PSCell. In NR, if the network entity has configured the UE to store and report the information related to the SCG activation and deactivation, the UE may log the duration of stay in the PSCell with SCG activated in the field timeSpent (as defined in TS 38.331).

[0097] In an embodiment, if the network entity has configured the UE to store and report the information related to the SCG activation and deactivation, the UE logs timeSpent to the duration of stay in the PSCell with SCG activated. If the network entity has not configured the UE to store and report the information related to the SCG activation and deactivation, the UE logs timeSpent to the duration of stay in the PSCell (i.e. including SCG activated and SCG deactivated, not considering the SCG activation status).

[0098] In an embodiment, the UE includes an indicator in MHI which indicates whether UE is logging information related to the time the UE has stayed in PSCell with SCG activated. The indicator informs the network whether the UE is logging timeSpent for the duration of stay in the PSCell or whether the UE is logging timeSpent for the duration of stay in the PSCell with SCG activated.

[0099] In an embodiment, If the UE supports PSCell mobility history information and based on change, or release of a PSCell while being connected to the current PCell, or based on release of a PSCell while entering 'camped normally' state or 'any cell selection' state or 'camped on any cell' state, the UE includes an entry for the PSCell mapped to the PCell, possibly after removing the oldest PSCell entry. Further, If the PSCell is changed or released while being connected to the current PCell, or if the PSCell is released while entering 'camped normally' state in the same serving cell which was previously the PCell, the UE may store and report the time spent in the previous PSCell with SCG activated (or SCG deactivated) while being connected to the current PCell / serving cell. Logging the activation time in this scenario helps the current PCell to decide whether to add or move to the same PSCell soon even if the radio conditions are favourable. If the SCG is deactivated, it means the user activity is less. So the MN may not add an SCG immediately.

[0100] Additionally, if the PSCell is released while entering 'any cell selection' state or 'camped on any cell' state from a suitable cell in RRC_CONNECTED state in NR or LTE, or if the PSCell is released while entering 'camped normally' state while previously in RRC_CONNECTED state in a PCell different from the current serving cell, UE may store and report the time spent in the previous PSCell with SCG activated while being connected to the current PCell / serving cell. This helps the new PCell whether to add SCG immediately or wait further before adding the SCG. If the MN identifies that time spent in SCG activated state in the previous PSCell is high while transitioning to RRC_CONNECTED, MN may add the PSCell even without receiving the SCG measurements (blind addition of the PSCell). Since the blind addition has a risk of SCG failure, if the MN identifies that time spent in SCG activated state in the previous PSCell is low, while transitioning to RRC_CONNECTED, MN may decide to avoid the risk and configure PSCell later, after configuring the measurements and receiving the measurement results.

[0101] In an embodiment, the above information is provided if the UE is configured to store and report SCG activation / deactivation related information in MHI. In an embodiment, the above information is provided if the UE is capable to store and report SCG activation / deactivation related information in MHI. In an embodiment, the above information is provided in field timeSpent in NR (or equivalent field in other RAT). In an embodiment, the above information is provided in a field other than timeSpent in NR (or equivalent field in other RAT).

[0102] In an embodiment, instead of timeSpent, percentage of time spent is provided.

[0103] In an embodiment, if the UE supports PSCell mobility history information and if:

[0104] - 　the UE continues to be connected to the same PSCell during the change of the PCell in RRC_CONNECTED, or

[0105] - 　the UE changes PSCell at the same time as the change of the PCell in RRC_CONNECTED, or

[0106] - 　the PSCell is released at the same time as the change of the PCell in RRC_CONNECTED, UE may include an entry for the PSCell mapped to the PCell, possibly after removing the oldest PSCell entry and UE may store and report the time spent in the previous PSCell with SCG activated (or SCG deactivated) while being connected to the current PCell / serving cell. This allows the new PCell to determine the strategy for SCG activation / deactivation. If the SCG was active in the previous PCell, the new PCell also may decide to keep SCG active. Similarly, if the SCG was not active in the previous PCell, new PCell may deactivate SCG. In another example, if the PSCell supports a selected set of slices and the activity in those slices are less, the PSCell will be deactivated mostly. So the current PCell may decide not to add the same PSCell even when the radio conditions are favourable.

[0107] In an embodiment, the above information is provided if the UE is configured to store and report SCG activation / deactivation related information in MHI. In an embodiment, the above information is provided if the UE is capable to store and report SCG activation / deactivation related information in MHI. In an embodiment, the above information is provided in field timeSpent in NR (or equivalent field in other RAT). In an embodiment, the above information is provided in a field other than timeSpent in NR (or equivalent field in other RAT). In an embodiment, instead of timeSpent, percentage of time spent is provided.

[0108] To optimize battery consumption and ensure fast usage of SCG, the system supports an activation and deactivation mechanism for SCG. When the SCG is deactivated, transmission via SCG RLC bearers is halted, and various control mechanisms ensure that there is no unnecessary uplink control signalling. The system also facilitates the monitoring of radio links and beam failure detection while SCG is deactivated. The SCG can be activated or deactivated based on network configurations such as PSCell addition, PSCell change, or handover procedures, with the UE required to adjust its behavior accordingly.

[0109] Moreover, mobility history information plays a crucial role in maintaining efficient connectivity during movement. The UE may report its mobility history when connecting to a cell, including records from both PCell and PSCell. The mobility history information is managed and stored according to predefined procedures, ensuring that the UE can maintain connectivity even during transitions between cells.

[0110] In an embodiment, Mobility history information may be as shown in Table 1.

[0111] [Table 1]

[0112]

[0113]

[0114]

[0115]

[0116] In an embodiment, Mobility history information may be as shown in Table 2.

[0117] [Table 2]

[0118]

[0119]

[0120]

[0121] In an embodiment, UE stores and reports both the time spent in PSCell and the time spent in PSCell with SCG activated in MHI. Time spent in PSCell with SCG activated (e.g. timeSpentwithSCGActivated) in MHI may be stored and reported in seconds, with range from 0 to N seconds. N can be typically 4095 seconds. If the Time spent in PSCell with SCG activated exceeds N, UE may store and report N, i.e. an approximate value may be reported instead of the actual time spent thereby keeping a balance between the memory of the UE and the need for optimization. Since the information related to each PSCell in relation to each PCell is logged, it is important to reduce the memory consumption while maintaining the advantages of receiving the information. Informing N such as 4095 will help both. If the SCG was activated for more than 4095 seconds, it indicates that the UE has been active in the PSCell well. So upper limit like 4095 will help the network to do acceptable level of optimisations with a minimal cost.

[0122] In an embodiment, UE stores and reports both the timeSpent in PSCell and timeSpentwithSCGActivated separately in MHI. It is also possible that UE stores reports Time spent in PSCell with SCG deactivated instead of timeSpentwithSCGActivated in MHI. Same embodiments related to reporting the time spent in PSCell with SCG activated will be applicable for this case.

[0123] In an embodiment, Mobility history information may be as shown in Table 3.

[0124] [Table 3]

[0125]

[0126]

[0127]

[0128] In an embodiment, the UE 102 stores and reports percentage of time with SCG activated in PSCell to the total time spent in the PSCell, instead of the time with SCG activated in the PSCell.

[0129] In an embodiment, Mobility history information may be as shown in Table 4.

[0130] [Table 4]

[0131]

[0132]

[0133]

[0134] The disclosure provides a method for logging PSCELL information in mobility history information (MHI), according to one of the embodiments enclosed.

[0135] The method includes reporting UE capability about supporting storage and reporting of information about the time the UE has spent in PSCell with SCG activated or deactivated in MHI. Further method includes receiving configuration for storage and reporting of information about the time the UE has spent in PSCell with SCG activated or deactivated in MHI. Furthermore, the method includes, including information about the time the UE has spent in PSCell with SCG activated or deactivated in the Mobility History Information.

[0136] The sequence of operations of the method need not be necessarily executed in the same order as they are presented. Further, one or more operations may be grouped together and performed in form of a single step, or one operation may have several sub-steps that may be performed in parallel or in sequential manner.

[0137] The disclosed method, or one or more operations of the system may be implemented using software including computer-executable instructions stored on one or more computer-readable media (e.g., non-transitory computer-readable media, such as one or more optical media discs, volatile memory components (e.g., DRAM or SRAM), or non-volatile memory or storage components (e.g., hard drives or solid-state non-volatile memory components, such as Flash memory components) and executed on a computer (e.g., any suitable computer, such as a laptop computer, net book, Web book, tablet computing device, smart phone, or other mobile computing device). Such software may be executed, for example, on a single local computer.

[0138] The method and system described in the disclosure provides various advantages and technical effects. The method and system described in the disclosure reduce network management traffic resulting in reduced energy consumption and enable proactive zero-touch resolution of network fault and performance degradation. Further, the method and system described in the disclosure enable AI-native network management support inside management function and / or managed function.

[0139] In the disclosure, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0140] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.

[0141] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a device or system or apparatus proceeded by "comprises ... a" does not, without more constraints, preclude the existence of other elements or additional elements in the device or system or apparatus.

[0142] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0143] It may be noted that, for convenience of explanation, the disclosure uses terms, states, parameters, and message structures as defined in the specifications of the 3rd Generation Partnership Project (3GPP), particularly those relating to Radio Access Network (RAN) procedures. More specifically, terms such as Primary Cell (PCell), Primary Secondary Cell Group Cell (PSCell), Secondary Cell Group (SCG), dual connectivity, mobility history information (MHI), visitedPSCellInfoList, VarMobilityHistoryReport, RRC_CONNECTED, RRC_INACTIVE, RRC_IDLE, camped normally, any cell selection, camped on any cell, New Radio (NR), and E-UTRA are to be interpreted in accordance with the relevant 3GPP technical specifications.

[0144] Unless otherwise stated, the use of such terminology in the disclosure is intended to be consistent with the meanings and behaviors defined by the applicable 3GPP standards and is provided solely to facilitate understanding of the described embodiments, without limiting the scope of the disclosure.

[0145] Disclosed herein are a method and User Equipment for logging mobility history information in a wireless communication system. In modern cellular networks supporting dual connectivity, a user equipment (UE) may operate with a Primary Cell (PCell) and, selectively, a Primary Secondary Cell Group Cell (PSCell) associated with a Secondary Cell Group (SCG). However, existing mobility history mechanisms do not reliably capture the time spent by the UE in the PSCell specifically during periods when the SCG is activated or deactivated, particularly across mobility events such as PSCell changes, PSCell releases, or suitable cell changes. This results in incomplete or inefficient mobility history reporting, limiting the network's ability to analyse UE mobility behaviour and optimize radio resource management. The disclosure addresses these limitations by enabling the UE to detect mobility events associated with a PCell or a PSCell, determine an activation duration representing time spent by the UE in the PSCell and time spent by the UE in the PSCell with the SCG activated, and log this information in Mobility History Information (MHI).

[0146] Fig. 1 illustrates an exemplary system environment 100 (also referred to as wireless communication system 100) in which embodiments of the disclosure may be practiced. The system environment 100 includes a user equipment (UE) 102 operating within a communication network 104. The communication network 104 provides radio access connectivity to the UE 102 through one or more serving cells. In an embodiment, the communication network 104 supports dual connectivity operation, in which the UE 102 is configured to connect with a Primary Cell (PCell) 106 and is further configurable to connect, activate, deactivate, change, add, or release a Primary Secondary Cell Group Cell (PSCell) 108. The UE 102 may maintain an active connection with the PCell 106 and may selectively establish or modify a connection with the PSCell 108 based on network configuration, mobility procedures, or UE state transitions. In such embodiments, addition of a PSCell, change of a PSCell, activation or deactivation of a Secondary Cell Group, or release of a PSCell is treated as a mobility event relevant for mobility history logging, even when the UE 102 remains connected to the PCell 106.sss.

[0147] The PCell 106 serves as a primary anchor cell for the UE 102 and is responsible for radio resource control (RRC) signalling, mobility management, and maintenance of the UE's connection state within the communication network 104. In an embodiment, the PCell 106 corresponds to a serving cell operating in a radio resource control connected state and remains associated with the UE 102 across mobility events unless explicitly changed or released by network procedures.

[0148] The PSCell 108 is associated with a Secondary Cell Group (SCG) that may be configured, activated, deactivated, changed, or released independently of the PCell 106. In an embodiment, the PSCell 108 provides additional radio resources, such as user plane capacity or throughput enhancement, when the SCG is activated. The activation state of the SCG associated with the PSCell 108 may vary over time based on network conditions, mobility procedures, or UE state transitions, and such activation or deactivation affects the duration for which the UE 102 effectively utilizes the PSCell 108. Mobility events involving the PCell 106 and the PSCell 108, including changes, releases, or state transitions, define boundaries for logging mobility history information by the UE 102, as described in subsequent embodiments.

[0149] The UE 102 may include, but is not limited to, a mobile phone, smartphone, tablet, laptop computer, wearable device, Internet-of-Things (IoT) device, vehicle-mounted communication device, or any other device capable of wireless communication in accordance with cellular communication standards.

[0150] The communication network 104 may comprise one or more radio access network nodes, such as base stations, configured to operate as the PCell 106 and the PSCell 108. The communication network 104 may support various radio resource control (RRC) states including, but not limited to, RRC_CONNECTED, RRC_INACTIVE, RRC_IDLE, camped-normally, any-cell-selection, and camped-on-any-cell states.

[0151] During operation, the UE 102 may experience mobility events associated with the PCell 106 and / or the PSCell 108. Such mobility events may include, for example, addition of the PSCell 108, change of the PSCell 108, release of the PSCell 108, change of the PCell or serving cell, or transitions between different radio resource control states. These mobility events may occur while the UE 102 is connected to the PCell 106, while the PSCell 108 is active, or during transitions between connected and camped states.

[0152] In accordance with embodiments of the disclosure, the UE 102 is configured to detect mobility events associated with the PCell 106 or the PSCell 108. In response to detecting a mobility event, the UE 102 determines an activation duration representing the time spent by the UE 102 in the PSCell 108 while the Secondary Cell Group is activated.

[0153] The UE 102 further logs the determined activation duration as part of Mobility History Information (MHI). In an embodiment, the logged mobility history information includes values indicating the time spent by the UE 102 in the PSCell 108 with the Secondary Cell Group activated. Such values may be stored using predefined fields within a mobility history data structure maintained by the UE 102.

[0154] The environment 100 further includes a network entity 110 configured to receive MHI from the UE 102. In an embodiment, the network entity 110 may include a network node, management function, or control function associated with the communication network 104. The UE 102 may report the mobility history information to the network entity 110 using a mobility history report, such as a VarMobilityHistoryReport.

[0155] In some embodiments, the mobility history information reported by the UE 102 includes time values represented in seconds within a predefined representable range. When an actual time spent by the UE 102 in the PSCell 108 with the Secondary Cell Group activated exceeds a maximum representable value, the UE 102 stores and reports the maximum value, thereby limiting memory usage while preserving useful mobility information.

[0156] Fig. 1 illustrates a logical representation of the system environment for explaining the concepts of the disclosure. The specific number of network entities, cells, and communication links shown are exemplary and are not intended to limit the scope of the disclosure. It is to be appreciated that, while Fig. 1 illustrates an exemplary dual connectivity configuration in which the UE 102 is connected to a Primary Cell (PCell) 106 and a Primary Secondary Cell Group Cell (PSCell) 108, the disclosure is not limited to the specific cell roles, connectivity arrangements, or radio access technologies depicted. Any communication system configuration in which a user equipment maintains a primary serving cell relationship and an additional secondary cell group association, and in which mobility events related to such cells may occur, is within the scope of the disclosure without limitation.

[0157] Further, the terms PCell, PSCell, Secondary Cell Group (SCG), serving cell, camped state, connected state, idle state, and cell selection state are used herein for ease of explanation and are to be interpreted broadly to encompass equivalent or analogous concepts defined in present or future wireless communication standards, including but not limited to 3GPP LTE, NR, and subsequent releases. Variations in signalling procedures, state definitions, or cell role assignments that achieve substantially the same mobility history logging behaviour are considered within the scope of the disclosure.

[0158] FIG. 2 illustrates the User Equipment (UE) 102 for logging mobility history information, in accordance with an embodiment of the disclosure. Referring to FIG. 2, the UE 102 described with respect to FIG. 1 is shown. The UE 102 is configured to establish and maintain radio access connectivity with one or more network entities via a communication network for communication operations and is further configured to autonomously detect mobility events and log Mobility History Information (MHI) associated with such mobility events involving a Primary Cell (PCell) 106 and a Primary Secondary Cell Group Cell (PSCell) 108.

[0159] In an embodiment, the UE 102 operates in a dual connectivity configuration in which the UE 102 is connected to a PCell 106 and is selectively configured with a PSCell 108 associated with a Secondary Cell Group (SCG). The UE 102 may transition among radio resource control (RRC) states including RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE, and may further enter cell selection-related states such as an any-cell-selection state or a camped-on-any-cell state. During operation, the UE 102 monitors changes in cell configuration, SCG configuration, serving cell identity, and RRC state transitions to detect mobility events. In an embodiment, detecting a mobility event comprises detecting a change of the PSCell 108 or a release of the PSCell 108, irrespective of whether the UE 102 remains connected to the same PCell 106 or transitions between RRC states.

[0160] In an embodiment, the mobility event detected by the UE 102 may include a change or release of the PSCell 108 while the UE 102 remains connected to the current PCell in an RRC_CONNECTED state. In another embodiment, the mobility event comprises release of the PSCell 108 while the UE 102 enters a camped normally state in the same serving cell that previously functioned as the PCell 106. In yet another embodiment, the UE 102 detects a mobility event when the PSCell 108 is released while the UE 102 transitions from an RRC_CONNECTED state in NR or LTE to an any-cell-selection state or a camped-on-any-cell state from a suitable cell. In a further embodiment, the mobility event comprises PSCell release while entering a camped normally state after the UE 102 was previously operating in an RRC_CONNECTED state with a PCell different from the current serving cell.

[0161] In an embodiment, the mobility event comprises a change of a suitable cell, including a change of the PCell 106 or serving cell to another cell, or a transition into an any-cell-selection state from a camped normally state, or into an any-cell-selection state or a camped-on-any-cell state from a suitable cell. In such scenarios, the UE 102 further determines the status of the PSCell 108 relative to the suitable cell change.

[0162] In one embodiment, the UE 102 continues to remain connected to the same PSCell 108 during the change of the PCell 106. In one embodiment, the UE 102 continues to remain connected to the same PSCell 108 during a change of the PCell 106. Although the PSCell 108 itself is not changed or released in this scenario, the change of the PCell 106 constitutes a mobility event because the PCell 106 acts as the primary control anchor for the UE 102. When the PCell 106 changes, the UE's control plane context, radio resource control configuration, and mobility management responsibilities are transferred from the source PCell to a target PCell. As a result, the coordination relationship between the new PCell 106 and the PSCell 108 is re-established or updated.

[0163] In particular, the new PCell 106 assumes responsibility for managing the UE's overall configuration, including control signalling, mobility decisions, and coordination of the Secondary Cell Group associated with the PSCell 108. This transition may involve reconfiguration of UE parameters, updating of serving cell identifiers, synchronization of control information, and reassignment of resource management responsibilities. Consequently, even though the PSCell 108 remains unchanged at the radio level, the effective operational context of the UE 102 with respect to the PSCell 108 is modified due to the change in the controlling PCell 106.

[0164] Accordingly, the UE 102 treats a change of the PCell 106 while remaining connected to the same PSCell 108 as a mobility event, since the change introduces a new mobility boundary for control-plane ownership and resource coordination. This mobility boundary defines a logical point at which ongoing tracking of time spent in the PSCell 108 with the Secondary Cell Group activated must be finalized and logged. Treating this scenario as a mobility event ensures accurate accounting of PSCell usage across PCell transitions and enables consistent mobility history logging irrespective of whether the PSCell itself is changed, released, or retained.

[0165] In another embodiment, the UE 102 changes the PSCell 108 at substantially the same time as the change of the PCell 106. In yet another embodiment, the UE 102 releases the PSCell 108 concurrently with the change of the PCell 106.

[0166] Based on detecting any of the above mobility events, the UE 102 determines an activation duration representing the time spent by the UE 102 in the PSCell 108 while the SCG is activated, and, in some embodiments, while the SCG is deactivated prior to release or change. The UE 102 then logs the determined information as part of Mobility History Information, thereby enabling accurate recording of PSCell-related usage across diverse mobility scenarios, RRC state transitions, and serving cell changes.

[0167] In an embodiment, the UE 102 logs the Mobility History Information in a standardized and structured format maintained within the UE memory. In one implementation, the MHI is organized as a visitedPSCellInfoList, which comprises one or more entries corresponding to PSCells 108 that were configured, activated, deactivated, changed, or released during operation of the UE 102. Each entry in the visitedPSCellInfoList may include, but not limited to, identifiers of the PSCell 108, timing-related information, and one or more values representing time spent by the UE 102 in the PSCell 108 while the Secondary Cell Group (SCG) was activated and, in some embodiments, while the SCG was deactivated prior to a mobility event.

[0168] In an embodiment, the UE 102 stores the time spent with the SCG activated in units of seconds within a predefined threshold value. The predefined threshold value defines a maximum value N that serves as a threshold for storage and reporting of the time information. During operation, the UE 102 identifies whether an accumulated time spent by the UE 102 in the PSCell 108 with the SCG activated exceeds the predefined threshold corresponding to the maximum value N. The predefined threshold value defines a maximum value N that serves as a threshold for storage and reporting of the time information. The maximum value N may be configured according to implementation constraints, encoding limitations, or standard-defined field sizes, and in one non-limiting example, N equals 4095 seconds.

[0169] During operation, the UE 102 identifies whether an accumulated time spent by the UE 102 in the PSCell 108 with the SCG activated exceeds the predefined threshold corresponding to the maximum value N. Upon identifying that the accumulated activation duration exceeds the maximum value N, the UE 102 applies threshold handling by capping the activation duration to N and storing and reporting the capped value instead of the actual accumulated duration. For example, when the accumulated activation duration is 5100 seconds, which exceeds the maximum value 4095 seconds, the UE 102 stores and reports the value 4095 seconds in the Mobility History Information...

[0170] By identifying that the accumulated time spent by the UE 102 in the PSCell 108 with the Secondary Cell Group activated exceeds a predefined threshold corresponding to a maximum representable value N, the UE 102 applies threshold handling to store and report a capped value equal to the predefined maximum. In this manner, when the actual time spent exceeds the maximum value N, the UE 102 stores and reports the threshold value instead of the actual accumulated duration.

[0171] By reporting an approximate but bounded value rather than the full accumulated time beyond the threshold, the UE 102 limits memory consumption and signalling overhead while maintaining sufficient accuracy for mobility optimization, Secondary Cell Group usage analysis, and network-side mobility analytics. This approach enables consistent and efficient reporting of PSCell usage while preserving the ability of the network entity 110 to infer relative mobility behaviour, SCG utilization patterns, and long-term usage trends without requiring unbounded storage or signalling resources.

[0172] In an example, logging of the visitedPSCellInfoList may be performed by the UE 102 based on detection of a mobility event, such as a PSCell change, PSCell release, suitable cell change, or RRC state transition. In an example, logging of the visitedPSCellInfoList may be performed autonomously by the UE 102 based on detection of a mobility event, such as a PSCell change, PSCell release, suitable cell change, or RRC state transition, without requiring an explicit request from the network entity 110. In another embodiment, logging may be performed continuously based on internal timers or counters that track the duration for which the PSCell 108 remains configured and the SCG remains activated or deactivated. The logged information may be updated at each mobility event to ensure that the recorded durations accurately reflect the UE's operational history.

[0173] In an embodiment, reporting of the visitedPSCellInfoList to the network entity 110 may be configurable. The UE 102 may transmit the VarMobilityHistoryReport in response to an explicit request from the network entity 110, for example as part of mobility management, load optimization, or radio resource management procedures. In another embodiment, the UE 102 may proactively report the Mobility History Information, such as during connection establishment, re-establishment, handover, or other network-defined reporting occasions. In yet another embodiment, reporting may be deferred and aggregated, allowing multiple mobility events to be included in a single VarMobilityHistoryReport. By logging Mobility History Information in a standardized list-based structure and supporting flexible reporting mechanisms, the UE 102 enables the network entity 110 to obtain meaningful insights into PSCell 108 usage, SCG activation behaviour, and UE mobility characteristics, while maintaining efficient use of UE memory and radio signalling resources.

[0174] In an embodiment, the UE 102 comprises a processor 202, a memory 204, an input / output (I / O) module 206, and a communication interface 208. It shall be noted that, in some embodiments, the UE 102 may include more or fewer components than those depicted in FIG. 2. The various components of the UE 102 may be implemented using hardware, software, firmware, or any combination thereof, and may be operably coupled to one another via communication buses, interconnects, or other suitable communication media.

[0175] In one embodiment, the processor 202 may be embodied as a multi-core processor, a single-core processor, or a combination thereof. For example, the processor 202 may be implemented using one or more processing devices such as a microprocessor, a controller, a digital signal processor (DSP), a microcontroller unit (MCU), a hardware accelerator, or a dedicated processing circuit.

[0176] In one embodiment, the memory 204 may store machine-executable instructions, referred to herein as instructions 205. The processor 202 executes the instructions 205 stored in the memory 204 to perform one or more operations described in the disclosure. Further, the memory 204 may store MHI, activation duration values, time spent with SCG activated value, visitedPSCellInfoList entries, threshold values, configuration parameters, and historical mobility records associated with previously detected mobility events. The memory 204 may include volatile memory, non-volatile memory, or a combination thereof, such as RAM, ROM, flash memory, or other semiconductor-based storage technologies.

[0177] In an embodiment, the I / O module 206 includes mechanisms configured to receive inputs from and provide outputs to a user of the UE 102. The I / O module 206 may include one or more input interfaces such as a keypad, touchscreen, microphone, or sensors, and one or more output interfaces such as a display, speaker, or haptic feedback unit. While the I / O module 206 is not directly involved in mobility history logging, it supports normal user interaction and operation of the UE 102.

[0178] In an embodiment, the communication interface 208 includes mechanisms configured to enable wireless communication between the UE 102 and one or more network entities via a communication network. The communication interface 208 may support one or more radio access technologies, including New Radio (NR) and E-UTRA. The communication interface 208 enables the UE 102 to report MHI, including activation duration values representing time spent in the PSCell with the SCG activated, to a network entity 110. The reporting may be performed using standardized signalling procedures defined in applicable communication specifications.

[0179] In an embodiment, the UE 102 is operatively coupled to a database 210. The database 210 may be configured to store MHI, visited PSCell records, activation duration values, threshold values, and historical mobility data. In some embodiments, the database 210 is integrated within the UE 102. In other embodiments, the database 210 is external to the UE 102 and accessible via a storage interface. The database 210 may include one or more storage units such as solid-state memory, flash storage, or other persistent storage technologies, enabling efficient storage and retrieval of mobility history information.

[0180] FIG. 3 illustrates a flow diagram of a method for logging mobility history information, in accordance with an embodiment of the disclosure.

[0181] In various embodiments, the UE 102 operates in a wireless communication system supporting dual connectivity, carrier aggregation, or multi-cell connectivity, where the UE 102 maintains a primary connection via a PCell 106 and is additionally configured with a PSCell associated with a Secondary Cell Group (SCG). The PSCell 108 provides supplementary radio resources that may be dynamically configured, activated, deactivated, changed, or released by the network.

[0182] The UE 102 continuously evaluates radio configuration state, cell association status, RRC state transitions, and SCG activation state to determine whether a mobility event has occurred that impacts the continuity or termination of PSCell usage.

[0183] At step 302, the UE 102 detects a mobility event associated with the PCell 106 or the PSCell 108. Detection may be performed by monitoring control plane signalling, configuration changes, and state transitions rather than relying on a single trigger. In an embodiment, the UE 102 may maintain internal state variables indicating but not limited to currently configured PCell identity, currently configured PSCell identity, SCG activation state, UE RRC state, and serving cell suitability status. Any change in these parameters is evaluated against predefined mobility detection rules stored in UE logic.

[0184] In one embodiment, the UE 102 may detect a mobility event when a PSCell change occurs. A PSCell 108 change may be identified when the UE 102 receives reconfiguration signalling that replaces a currently configured PSCell with a different PSCell. This may occur due to load balancing, radio quality variation, network topology optimization, or handover preparation. Internally, the UE 102 may compare the previously stored PSCell identifier with the newly configured PSCell identifier. If the identifiers differ, the UE 102 determines that the association with the previous PSCell 108 has terminated. Even if the UE 102 remains connected to the same PCell and continues SCG operation with a new PSCell 108, the UE 102 treats the termination of the previous PSCell108 association as a mobility event because the continuity of time spent in the previous PSCell 108 has ended. This ensures that time accounting is bounded strictly to the lifecycle of each PSCell association.

[0185] In another embodiment, the UE 102 may detect a mobility event when the PSCell 108 is released. PSCell 108 release may occur when the network reconfigures the SCG or explicitly removes the PSCell 108 as part of mobility management, resource optimization, fallback procedures, or RRC state transitions. The UE 102 may detect PSCell 108 release based on receipt of signalling indicating removal of the PSCell 108 configuration or deactivation of the SCG. The UE 102 may update its internal state to reflect that no PSCell remains associated. The UE 102 may treat PSCell release as a mobility event because the PSCell 108 association ends definitively, requiring finalization of SCG-related timing and logging.

[0186] In another embodiment, the UE 102 detects a mobility event when the PSCell 108 changes or is released while the UE 102 continues to maintain a connection with the current PCell. In an example scenario, the UE 102 remains in an RRC_CONNECTED state with the PCell, and the serving cell identity does not change. However, the SCG topology changes due to PSCell 108 modification. The UE 102 differentiates this scenario from PCell mobility by determining that the PCell 106 configuration remains unchanged and that the mobility event is confined to the PSCell layer. The UE 102 treats such events as mobility events to ensure that PSCell-specific usage is logged independently of PCell continuity.

[0187] In another embodiment, the UE 102 may detect a mobility event when the PSCell 108 is released as the UE 102 transitions to a camped normally state on the same serving cell that previously operated as the PCell. In an embodiment, the UE 102 transitions from an RRC_CONNECTED state to a camped normally state due to inactivity, network instruction, or release procedures, without changing the serving cell identity. During this transition, the PSCell and SCG configuration terminate as part of the RRC state change. The UE 102 detects that although the serving cell remains the same, the PSCell association ends, and therefore identifies a mobility event relevant to PSCell history logging. PSCell Release During Cell Selection or Camped States

[0188] In another embodiment, the UE 102 may detect a mobility event when the PSCell is released while the UE 102 enters an any-cell-selection state or a camped-on-any-cell state from a suitable cell in an RRC_CONNECTED state. Such transitions may occur for example but not limited due to radio link failure, loss of coverage, or network-initiated mobility actions.

[0189] In a further embodiment, the UE 102 detects PSCell release when entering a camped normally state after previously operating in an RRC_CONNECTED state with a PCell different from the current serving cell. Here, the UE 102 identifies that both the PCell association and PSCell association have terminated, and that the termination coincides with a broader mobility context.

[0190] In another embodiment, the UE 102 may detect a mobility event when a suitable cell changes. A suitable cell includes a PCell or a serving cell meeting cell selection criterion. The UE 102 may detect such a change when transitioning from one suitable cell to another, or when entering an any-cell-selection or camped-on-any-cell state. In one case, the UE 102 determines that the PSCell remains connected during the suitable cell change. The UE 102 treats the suitable cell change as a mobility event boundary and finalizes PSCell timing accumulated prior to the PCell transition. In another case, the UE 102 may detect that PSCell changes concurrently with the suitable cell change. The UE 102 finalizes timing for the previous PSCell and initializes tracking for the newly configured PSCell. In another case, the UE 102 detects that PSCell is released concurrently with the suitable cell change and logs the PSCell history accordingly.

[0191] At step 304, the UE 102 may determine an activation duration representing time spent in the PSCell with the SCG activated. In an embodiment, the UE 102 may maintain activation duration timer that increments only during periods when the SCG is activated. The timer is started or resumed based on SCG activation and paused or stopped based on SCG deactivation or PSCell release. If the SCG is activated again after the SCG deactivation before the mobility event, the duration SCG is activated can include the time spent in SCG activated state previously also, i.e., SCG activation duration can be accumulated time.

[0192] In an embodiment, the UE 102 supports SCG deactivation without immediate PSCell release. Based on SCG deactivation, the UE 102 stops incrementing the activation duration timer and retains the accumulated value. If a mobility event occurs thereafter, the UE 102 logs the retained activation duration as time spent in the previous PSCell with SCG deactivated prior to the mobility event.

[0193] In another embodiment, the UE 102 applies threshold handling to the activation duration representing the time spent in the PSCell 108 with the SCG activated. In an embodiment, the activation duration is measured, stored, and reported in units of seconds within a predefined representable range from zero to a maximum value N. The maximum value N may be configured according to implementation constraints and, in one non-limiting example, N equals 4095 seconds. When the accumulated activation duration exceeds the maximum value N, the UE 102 caps the activation duration to N and stores and reports the capped value. By reporting an approximate value instead of the actual time spent beyond N, the UE 102 limits memory consumption and signalling overhead while maintaining sufficient accuracy for mobility optimization and network analytics. In an example, when the activation duration is 5100 seconds, which is higher than the maximum value 4095 seconds, the value 4095 is stored in the memory.

[0194] At step 306, the UE 102 logs the determined timing information in Mobility History Information. In an embodiment, logging the time spent by the UE 102 in the PSCell 108 with the SCG activated involves storing time spent with SCG activated in a visitedPSCellInfoList of the MHI. The time spent with SCG activated is expressed in units of seconds within a predefined representable range and are stored as part of a visitedPSCellInfoList maintained in a memory of the UE.

[0195] FIG. 4 illustrates a sequence flow of a method 400 for logging mobility history information by a user equipment (UE) and reporting a network entity, in accordance with some embodiments of the disclosure.

[0196] At step 402, the UE 102 may detect a mobility event associated with a Primary Cell (PCell) 106 or a Primary Secondary Cell Group Cell (PSCell) 108. In various embodiments, the UE 102 performs the detection autonomously based on monitoring of radio conditions, radio resource control (RRC) state transitions, and cell configuration changes. In other embodiments, the detection is event-driven, for example in response to signalling received from the network entity.

[0197] In one embodiment, the UE 102 may detect the mobility event by identifying a change of the PSCell 108 or a release of the PSCell 108, such as through RRC reconfiguration signalling, SCG deactivation, or PSCell deconfiguration. In another embodiment, the UE detects the mobility event based on a change of a suitable cell comprising the PCell 106 or a serving cell or based on entry into an any-cell-selection state, a camped-normally state, or a camped-on-any-cell state.

[0198] In further embodiments, the UE 102 detects the mobility event while remaining connected to a current PCell, while transitioning between suitable cells, or while the PSCell remains connected, changes, or is released concurrently with a PCell 106 or serving cell change. Any event that terminates or modifies the association between the UE 102 and the PSCell 108 or the UE 102 and the PCell 106 is treated as a mobility event relevant for mobility history logging.

[0199] At step 404, the UE 102 may determine timing information associated with the PSCell. In an embodiment, the UE 102 determines a time spent with SCG activated value representing a duration within the timeSpent during which the Secondary Cell Group (SCG) was activated. In various embodiments, the UE 102 may track SCG activation and deactivation using one or more timers or counters while the PSCell 108 is configured and derives the time spent with SCG activated based on accumulated SCG activation intervals.

[0200] In an embodiment, the UE 102 applies threshold handling to time spent with SCG activated value. If a determined duration exceeds a predefined maximum representable value, the UE 102 stores a capped value. The durations may be represented in units of seconds within a predefined range from zero to a maximum value N, for example 4095 seconds, to balance memory usage, reporting overhead, and optimization accuracy.

[0201] At step 406, the UE 102 logs the determined time spent with SCG activated in Mobility History Information (MHI). In an embodiment, the UE 102 stores time spent with SCG activated value as part of an entry in a visitedPSCellInfoList maintained in UE memory. In various embodiments, the logged time spent with SCG activated correspond to time spent in a previous PSCell while remaining connected to a current PCell or serving cell, time spent in a PSCell 108 prior to PSCell release, or time spent in a PSCell 108 when the SCG is deactivated prior to or during a mobility event. The UE 102 may log the information irrespective of whether the SCG remains activated or is deactivated at the time of logging.

[0202] At step 408, the UE 102 may report the stored mobility history information to a network entity 110 by transmitting the visitedPSCellInfoList in a VarMobilityHistoryReport. In one example, the reporting is initiated autonomously by the UE, for example based on internal reporting criteria, periodic reporting configuration, or occurrence of mobility events. In another example, the reporting is triggered in response to a request or configuration from the network entity 110. Accordingly, reporting of the visitedPSCellInfoList may be UE-initiated, network-initiated, or conditionally triggered, without limitation.

[0203] Consequently, the disclosure provides a user equipment (UE) and a method for accurately logging mobility history information in a wireless communication system by detecting mobility events associated with a Primary Cell (PCell) and a Primary Secondary Cell Group Cell (PSCell). The disclosed approach enables the UE to detect a wide range of mobility scenarios, including PSCell change, PSCell release, suitable cell change, and radio resource control (RRC) state transitions, while operating in single- or dual-connectivity configurations. Based on detection of such mobility events, the UE determines precise activation durations representing time spent in the PSCell with a Secondary Cell Group (SCG) activated or deactivated, using internal timers and counters that continuously track SCG state over time.

[0204] The disclosed method further supports threshold-based handling of activation duration values, whereby accumulated time values may be capped to a predefined maximum representable range to balance memory usage, signalling efficiency, and reporting accuracy. The UE logs the resulting mobility history information in a structured format and report the logged mobility history information to a network entity.

[0205] By enabling precise, consistent, and standardized logging of PSCell- and SCG-related mobility behaviour across heterogeneous mobility scenarios, the disclosed system and method provide the network with improved visibility into UE mobility patterns and secondary cell utilization. This facilitates more informed network optimization decisions, including mobility management, resource allocation, and dual-connectivity optimization, while avoiding ambiguity, double counting, or excessive signalling overhead. As a result, the disclosure improves both UE efficiency and network-level performance across varying radio conditions, deployment architectures, and mobility profiles.

[0206] Fig. 5 illustrates a block diagram of an exemplary computer system 500, for implementing embodiments consistent with the disclosure. The computer system 500 may be, without limitation to, the UE 102 and the network entity 110. The computer system 500 may include a central processing unit ("CPU" or "processor") 501. The processor 501 may include at least one data processor for executing processes. The processor 501 may include specialized processing units such as, integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc.

[0207] The processor 501 may be disposed in communication with one or more input / output (I / O) devices 508 and 509 via I / O interface 507. The I / O interface 507 may employ communication protocols / methods such as, without limitation, audio, analog, digital, monaural, RCA, stereo, IEEE-1394, serial bus, universal serial bus (USB), infrared, PS / 2, BNC, coaxial, component, composite, digital visual interface (DVI), high-definition multimedia interface (HDMI), RF antennas, S-Video, VGA, IEEE 902.n / b / g / n / x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), WiMax, or the like), etc.

[0208] Using the I / O interface 507, the computer system 500 may communicate with one or more I / O devices 508 and 509. For example, the input devices 508 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touchpad, trackball, stylus, scanner, storage device, transceiver, video device / source, etc. The output devices 509 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), plasma, Plasma display panel (PDP), Organic light-emitting diode display (OLED) or the like), audio speaker, etc.

[0209] In some embodiments, the processor 501 may be disposed in communication with external elements such as external computer systems, servers, network elements. The network interface 510 may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10 / 100 / 1000 Base T), transmission control protocol / internet protocol (TCP / IP), token ring, IEEE 802.11a / b / g / n / x, etc.

[0210] In some embodiments, the processor 501 may be disposed in communication with a memory 503 (e.g., RAM, ROM, etc.) via a storage interface 502. The storage interface 502 may connect to memory 503 including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as, serial advanced technology attachment (SATA), Integrated Drive Electronics (IDE), IEEE-1394, Universal Serial Bus (USB), fibre channel, Small Computer Systems Interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, Redundant Array of Independent Discs (RAID), solid-state memory devices, solid-state drives, etc.

[0211] The memory 503 may store a collection of program or database components, including, without limitation, user interface 504, an operating system 505, a web browser 506 etc. In some embodiments, computer system 500 may store user / application data, such as, the data, variables, records, etc., as described in this disclosure. Such databases may be implemented as fault-tolerant, relational, scalable, secure databases such as Oracle® or Sybase®.

[0212] The operating system 505 may facilitate resource management and operation of the computer system 500. Examples of operating systems include, without limitation, APPLE MACINTOSH® OS X, UNIX®, UNIX-like system distributions (e.g., BERKELEY SOFTWARE DISTRIBUTIONTM (BSD), FREEBSDTM, NETBSDTM, OPENBSDTM, etc.), LINUX DISTRIBUTIONSTM (e.g., RED HATTM, UBUNTUTM, KUBUNTUTM, etc.), IBMTM OS / 2, MICROSOFTTM WINDOWSTM (XPTM, VISTATM / 7 / 8, 10 etc.), APPLE® IOSTM, GOOGLE® ANDROIDTM, BLACKBERRY® OS, or the like.

[0213] In some embodiments, the computer system 500 may implement the web browser 506 stored program components. The web browser 506 may be a hypertext viewing application, such as MICROSOFT® INTERNET EXPLORER®, GOOGLETM CHROMETM, MOZILLA® FIREFOX®, APPLE® SAFARI®, etc. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport Layer Security (TLS), etc. Web browsers 706 may utilize facilities such as AJAX, DHTML, ADOBE® FLASH®, JAVASCRIPT®, JAVA®, Application Programming Interfaces (APIs), etc. In some embodiments, the computer system 500 may implement a mail server stored program component. The mail server may be an Internet mail server such as Microsoft Exchange, or the like. The mail server may utilize facilities such as Active Server Pages (ASP), ACTIVEX®, ANSI® C++ / C#, MICROSOFT®, .NET, CGI SCRIPTS, JAVA®, JAVASCRIPT®, PERL®, PHP, PYTHON®, WEBOBJECTS®, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFT® exchange, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), or the like. In some embodiments, the computer system 700 may implement a mail client stored program component. The mail client may be a mail viewing application, such as APPLE® MAIL, MICROSOFT® ENTOURAGE®, MICROSOFT® OUTLOOK®, MOZILLA® THUNDERBIRD®, etc.

[0214] The described operations may be implemented as a method, system or article of manufacture using standard programming and / or engineering techniques to produce software, firmware, hardware, or any combination thereof.　The described operations may be implemented as code maintained in a "non-transitory computer readable medium", where a processor may read and execute the code from the computer readable medium. The processor is at least one of a microprocessor and a processor capable of processing and executing the queries. A non-transitory computer readable medium may include media such as magnetic storage medium (e.g., hard disk drives, floppy disks, tape, etc.), optical storage (CD-ROMs, DVDs, optical disks, etc.), volatile and non-volatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs, SRAMs, Flash Memory, firmware, programmable logic, etc.), etc. Further, non-transitory computer-readable media may include all computer-readable media except for a transitory. The code implementing the described operations may further be implemented in hardware logic (e.g., an integrated circuit chip, Programmable Gate Array (PGA), Application Specific Integrated Circuit (ASIC), etc.).

[0215] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words "comprising," "having," "containing," and "including," and other similar forms are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. It must also be noted that as used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0216] Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the disclosure. A computer readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term "computer readable medium" should be understood to include tangible items and exclude carrier waves and transient signals, i.e., are non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media.

[0217] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the embodiments of the disclosure is intended to be illustrative, but not limiting, of the scope of the disclosure.

[0218] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:identifying a change or a release of at least one of a primary cell (PCell) or a primary secondary cell (PSCell);based on the change or the release of the at least one of the PCell or the PSCell, including an entry in a visited PSCell information list; andif the UE supports storing and reporting secondary cell group (SCG) activation information in mobility history information, setting a first field of the included entry to a time spent in a previous PSCell with a SCG activated.2.The method of claim 1, wherein setting the first field of the included entry includes:identifying whether the time spent in the previous PSCell with the SCG activated exceeds a certain value; andif the time spent in the previous PSCell with the SCG activated exceeds the certain value, setting the first field to the certain value.3.The method of claim 1 or 2, further comprising:setting a second field of the included entry as a time spent in the previous PSCell.4.The method of any one of claims 1 to 3, wherein the change or the release of the at least one of the PCell or the PSCell includes the change, or the release of the PSCell while being connected to a current PCell, or the release of the PSCell while entering a 'camped normally' state or an 'any cell selection' state or a 'camped on any cell' state.5.The method of claim 4, wherein setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated includes:if the PSCell is changed or released while being connected to the current PCell, or if the PSCell is released while entering the 'camped normally' state in a same serving cell which was previously the PCell, or if the PSCell is released while entering the 'any cell selection' state or the 'camped on any cell' state from a suitable cell in a radio resource control (RRC) connected state, or if the PSCell is released while entering the 'camped normally' state while previously in the RRC connected state in a PCell different from a current serving cell,　if the UE supports storing and reporting the SCG activation information in the mobility history information, setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated.6.The method of any one of claims 1 to 3, wherein the change or the release of the at least one of the PCell or the PSCell includes a change of a suitable cell, comprising the PCell or a serving cell, to an another cell, or entering an 'any cell selection' state from a 'camped normally' state or entering an 'any cell selection' state or a 'camped on any cell' state from the suitable cell.7.The method of claim 6, wherein setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated includes:if the UE continues to be connected to the same PSCell during the change of the PCell in a radio resource control (RRC) connected state, or if the UE changes the PSCell at a same time as the change of the PCell in the RRC connected state, or if the PSCell is released at the same time as the change of the PCell in the RRC connected state,　if the UE supports storing and reporting the SCG activation information in the mobility history information, setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated.8.A user equipment (UE) in a wireless communication system, the UE comprising:a processor; anda memory storing instructions which, when executed by the processor, cause the UE to:identify a change or a release of at least one of a primary cell (PCell) or a primary secondary cell (PSCell);based on the change or the release of the at least one of the PCell or the PSCell, include an entry in a visited PSCell information list; andif the UE supports storing and reporting secondary cell group (SCG) activation information in mobility history information, set a first field of the included entry to a time spent in a previous PSCell with a SCG activated.9.The UE of claim 8, wherein setting the first field of the included entry includes:identifying whether the time spent in the previous PSCell with the SCG activated exceeds a certain value; andif the time spent in the previous PSCell with the SCG activated exceeds the certain value, setting the first field to the certain value.10.The UE of claim 8 or 9, wherein the instructions further cause the UE to:set a second field of the included entry as a time spent in the previous PSCell.11.The UE of any one of claims 8 to 10, wherein the change or the release of the at least one of the PCell or the PSCell includes the change, or the release of the PSCell while being connected to a current PCell, or the release of the PSCell while entering a 'camped normally' state or an 'any cell selection' state or a 'camped on any cell' state.12.The UE of claim 11, wherein setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated includes:if the PSCell is changed or released while being connected to the current PCell, or if the PSCell is released while entering the 'camped normally' state in a same serving cell which was previously the PCell, or if the PSCell is released while entering the 'any cell selection' state or the 'camped on any cell' state from a suitable cell in a radio resource control (RRC) connected state, or if the PSCell is released while entering the 'camped normally' state while previously in the RRC connected state in a PCell different from a current serving cell,　if the UE supports storing and reporting the SCG activation information in the mobility history information, setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated.13.The UE of any one of claims 8 to 10, wherein the change or the release of the at least one of the PCell or the PSCell includes a change of a suitable cell, comprising the PCell or a serving cell, to an another cell, or entering an 'any cell selection' state from a 'camped normally' state or entering an 'any cell selection' state or a 'camped on any cell' state from the suitable cell.14.The UE of claim 13, wherein setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated includes:if the UE continues to be connected to the same PSCell during the change of the PCell in a radio resource control (RRC) connected state, or if the UE changes the PSCell at a same time as the change of the PCell in the RRC connected state, or if the PSCell is released at the same time as the change of the PCell in the RRC connected state,　if the UE supports storing and reporting the SCG activation information in the mobility history information, setting the first field of the included entry to the time spent in the previous PSCell with the SCG activated.15.A non-transitory computer readable storage medium storing instructions which, when executed by a processor of a user equipment (UE), cause the UE to implement the method of any one of claims 1 to 7.

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