Method for processing conditional configuration stored in UE

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system supporting a higher data rate than a fourth generation (4G) system with an Internet of Things (IoT) technology. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, healthcare, digital education, smart retail, security and safety services. In one embodiment, a method performed by a UE is provided. The method includes receiving a first message for configuring a second base station from a first base station connected to the UE; receiving a second message including a conditional primary and secondary cell (PSCell) change (CPC) configuration from the second base station, the CPC configuration including at least one configuration for at least one candidate PSCell and at least one condition for triggering CPC execution for each of at least one candidate PSCell; storing the CPC configuration; and releasing the stored CPC configuration in the event that a third message for releasing the secondary cell group of the second base station is received from the first base station.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly to a method and a user equipment (UE) for processing a conditional configuration stored in a UE in the wireless communication system. Background Art

[0002] In order to meet the increased demand for wireless data traffic since the deployment of the 4th generation (4G) communication system, efforts have been made to develop an improved 5th generation (5G) or quasi-5G communication system. 5G or quasi-5G communication systems are also referred to as "super 4G networks" or "post-long term evolution (LTE) systems". 5G communication systems are considered to be implemented in higher frequency (mmWave (millimeter wave)) bands, such as the 60GHz band, to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed for 5G communication systems. In addition, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0003] The Internet, a human-centered connected network in which humans generate and consume information, is now evolving toward the Internet of Things (IoT), in which distributed entities such as things exchange and process information without human intervention. The Internet of Everything (IoE), which is formed by combining IoT technology with big data processing technology through connection with cloud servers, has emerged. Since IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology", sensor networks, machine-to-machine (M2M) communication, machine-type communication (MTC), etc. have been recently studied. Such an IoT environment can provide intelligent Internet technology services to create new value for human life by collecting and analyzing data generated among connected things. Through the integration and combination between existing information technology (IT) and various industrial applications, IoT can be applied to a variety of fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Accordingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC, and M2M communications can be implemented through beamforming, MIMO, and array antennas. The application of cloud radio access networks (RANs) as the above-mentioned big data processing technology can also be considered as an example of the fusion between 5G technology and IoT technology.

[0005] The fifth generation (5G) communication system, i.e., New Radio (NR), is being developed to meet the growing demand for broadband through enhanced mobile broadband (eMBB), while also supporting new use cases of ultra-reliable low latency communications (URLLC) and massive machine type communications (mMTC). NR is an air interface based on orthogonal frequency division multiplexing (OFDM) and is designed to support a wide range of 5G device types, services, deployments, and spectrum. The network monitors UE behavior and provides the necessary resources to the UE to perform any operation required by the UE. The operation can be, for example, but not limited to, data uplink, data downlink, and calls. The signal strength and quality experienced by the UE varies depending on the proximity of the UE to the next generation Node B, i.e., gNB. UEs near the cell are expected to have better signal conditions than UEs far away from the gNB, i.e., cell edge situation.

[0006] Furthermore, a Radio Access Network (RAN) node in NR or an eNB in ​​gNB / Long Term Evolution (LTE) always maintains a context on the UE with which it is in an active Radio Resource Connection (RRC) connection. At any point in time, the gNB can handover the mobile device / UE from its control (i.e. source cell) to other gNB or other cell (i.e. target cell), thereby transferring the entire context of the UE to the target cell. This decision is made by the network, optionally based on assistance information received from the UE, with the help of measurement reports about neighboring cells. In other words, the gNB configures the UE to measure the signal conditions of the serving cell and neighboring cells that may belong to different gNBs. There are specific measurement criteria and specific reporting criteria, both of which are configured by the serving gNB. Due to various reasons like weak signal conditions, heavy load on the serving gNB, etc., the serving gNB can handover the UE to a neighboring cell or a target gNB, which can be done based on assistance information in the form of measurement reports received from the UE.

[0007] In NR, conditional handover (CHO) and conditional PSCell change (CPC) are introduced. In CHO, the network first provides the candidate target PCell configuration to the UE, and evaluates the conditions of these candidates. Once any candidate cell meets the configured conditions, a conditional handover to the candidate cell is performed. Similarly, for CPC, the secondary node (SN) first provides the candidate target PSCell configuration to the UE, and evaluates the conditions of these candidates. Once any candidate cell meets the configured conditions, a conditional PSCell change to the candidate cell is performed.

[0008] It would therefore be desirable to address these shortcomings or at least provide useful alternatives. Summary of the invention

[0009] Technical issues

[0010] For a more efficient communication system, a method for handling conditional configuration stored in a UE is needed.

[0011] Technical Solution

[0012] Therefore, an embodiment of the present disclosure discloses a method for processing a conditional configuration stored in a UE. The method includes receiving, by the UE, a radio resource control (RRC) message indicating the release of a secondary cell group (SCG) from a master node (MN). In addition, the method includes, in response to receiving an RRC message indicating the release of the SCG, releasing, by the UE, at least one of a stored conditional PSCell change (CPC) configuration and a variable storing the CPC configuration.

[0013] In one embodiment, the method further comprises detecting, by the UE, at least one measurement identifier associated with the stored CPC configuration, and removing, by the UE, the at least one measurement identifier associated with the stored CPC configuration in response to releasing the stored CPC configuration.

[0014] In one embodiment, the method also includes, for each measurement identifier of at least one measurement identifier configured for a source special cell (SpCell), determining, by the UE, whether the reporting configuration has a reporting type set as a conditional triggering configuration, and removing, by the UE, the reporting configuration with a matching reporting configuration identifier from a reporting configuration list within the VarMeasConfig for the reporting configuration identifier.

[0015] In one embodiment, the method further includes removing, by the UE, the measurement object having a matching measurement object identifier (measObjectId) from a measurement object list (measObjectList) within VarMeasConfig if the measurement object identifier (measObjectId) is associated only with a report configuration (reportConfig) having a report type set to a conditional trigger configuration (condTriggerConfig).

[0016] In one embodiment, the method further comprises removing, by the UE, the measurement identifier having the matching measurement identifier from a measurement identifier list within the VarMeasConfig.

[0017] In one embodiment, the method further comprises, in response to releasing the stored CPC configuration, releasing, by the UE, the measurement object associated with the CPC.

[0018] In one embodiment, the measurement object includes at least one of a frequency to be monitored, a list of cells to be monitored, cell information, and frequency offset information.

[0019] In one embodiment, the release of the SCG is received without the network explicitly requiring the UE to release the stored CPC configuration.

[0020] In one embodiment, at least one of a CPC configuration stored on the UE and a variable storing the CPC configuration is autonomously released.

[0021] In one embodiment, the MN is one of an Evolved-UMTS Terrestrial Radio Access Network (E-UTRA) and a New Radio (NR) network.

[0022] In one embodiment, a method performed by a UE is provided. The method includes: receiving a first message for configuring a second base station from a first base station connected to the UE; receiving a second message including a conditional primary secondary cell (PSCell) change (CPC) configuration from the second base station, the CPC configuration including at least one configuration for at least one candidate PSCell and at least one condition for triggering CPC execution for each of the at least one candidate PSCell; storing the CPC configuration; and releasing the stored CPC configuration in the event that a third message for releasing a secondary cell group of the second base station is received from the first base station.

[0023] In one embodiment, a UE is provided. The UE includes: a transceiver; and a controller coupled to the transceiver and configured to: receive a first message for configuring a second base station from a first base station connected to the UE, receive a second message including a conditional primary secondary cell (PSCell) change (CPC) configuration from the second base station, the CPC configuration including at least one configuration for at least one candidate PSCell and at least one condition for triggering CPC execution for each of the at least one candidate PSCell, store the CPC configuration, and release the stored CPC configuration when a third message for releasing the secondary cell group of the second base station is received from the first base station.

[0024] Accordingly, an embodiment of the present disclosure provides a UE for processing a conditional configuration stored in the UE. The UE includes a processor coupled to a memory. The processor is configured to receive an RRC message indicating the release of the SCG from the MN. In addition, the processor is configured to release at least one of the stored CPC configuration and the variable storing the CPC configuration in response to receiving the RRC message indicating the release of the SCG.

[0025] These and other aspects of the embodiments of the present disclosure will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. However, it should be understood that the following description, although indicating preferred embodiments and many of their specific details, is given by way of illustration and not limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from their spirit, and the embodiments herein include all such modifications.

[0026] Advantageous Effects of the Invention

[0027] The main purpose of the embodiments of this document is to provide a method for processing conditional configurations and conditional failures stored in a UE, so that the UE has no ambiguity about the CHO configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present disclosure is shown in the accompanying drawings, and the same reference numerals indicate corresponding parts in all the drawings. The embodiments of the present invention will be better understood through the following description in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a sequence diagram illustrating that a UE retains a stored CPC configuration and a corresponding measurement configuration when receiving an SCG release without a CPC release from the network;

[0030] Figure 2 is a sequence diagram illustrating a provided method for a UE to autonomously clear a stored CPC configuration and a corresponding measurement configuration when receiving an SCG release without a CPC release from a network according to an embodiment of the present disclosure;

[0031] Figure 3 An overview of a wireless communication system according to an embodiment of the present disclosure is shown, wherein a UE autonomously removes a stored CPC configuration and a corresponding measurement configuration upon receiving an SCG release from the network;

[0032] Figure 4A is a flow chart illustrating a method for autonomously removing a stored CPC configuration and a corresponding measurement configuration upon receiving an SCG release from a network according to an embodiment of the present disclosure;

[0033] Figure 4B is a flow chart illustrating a method for autonomously removing a stored CPC configuration and a corresponding measurement configuration upon receiving an SCG release from a network according to an embodiment of the present disclosure;

[0034] Figure 4C is a flow chart illustrating a method for autonomously removing a stored CPC configuration and a corresponding measurement configuration upon receiving an SCG release from a network according to an embodiment of the present disclosure;

[0035] Figure 5 A UE according to an embodiment of the present disclosure is shown; and

[0036] Figure 6 A base station according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0037] Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives are meant to include, but are not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may mean including, included, interconnected, containing, contained within, connected to or connected with, coupled to or coupled with, communicable with, cooperating with, interlaced, juxtaposed, proximate, bound to or bound with, having, having a property of, etc.; and the term "controller" means any device, system, or part thereof that controls at least one operation; such a device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0038] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data, or parts thereof suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD), or any other type of memory. "Non-transitory" computer-readable media do not include wired, wireless, optical, or other communication links that transmit temporary electrical or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and then rewrite, such as rewritable optical disks or erasable storage devices.

[0039] Definitions for other specific words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0040] Discussed below Figures 1 to 6 The various embodiments used to describe the principles of the present disclosure in this patent document are only for illustration and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure may be implemented in any appropriately arranged system or device.

[0041] The embodiments herein and their various features and advantageous details are more fully explained with reference to the non-limiting embodiments shown in the accompanying drawings and described in detail in the following description. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily confuse the embodiments herein. In addition, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. As used herein, the term "or" refers to a non-exclusive or, unless otherwise specified. The examples used herein are intended only to facilitate understanding of the ways in which the embodiments herein can be practiced, and to enable those skilled in the art to practice the embodiments herein. Therefore, the examples should not be interpreted as limiting the scope of the embodiments herein.

[0042] As is conventional in the art, embodiments may be described and illustrated in terms of blocks that perform one or more functions described. These blocks may be referred to herein as managers, units, modules, hardware components, etc., physically implemented by analog and / or digital circuits (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hard-wired circuits, etc.), and may optionally be driven by firmware. For example, the circuit may be embodied in one or more semiconductor chips, or embodied on a substrate support such as a printed circuit board. The circuits constituting the blocks may be implemented by dedicated hardware or processors (such as one or more programmed microprocessors and associated circuits) or by a combination of dedicated hardware that performs certain functions of the blocks and processors that perform other functions of the blocks. Without departing from the scope of the present disclosure, each block of the embodiment may be physically separated into two or more interacting and discrete blocks. Similarly, the blocks of the embodiment may be physically combined into more complex blocks without departing from the scope of the present disclosure.

[0043] Therefore, the embodiments herein provide a method for processing a conditional configuration stored in a UE. The method includes receiving, by the UE, an RRC message indicating the release of an SCG from an MN. In addition, the method includes, in response to receiving an RRC message indicating the release of the SCG, releasing, by the UE, at least one of the stored CPC configuration and a variable storing the CPC configuration.

[0044] Referring now to the drawings, and more particularly to Figures 2 to 6 , showing a preferred embodiment.

[0045] Figure 1 is a sequence diagram showing that a UE (100) retains a stored CPC configuration and a corresponding measurement configuration when receiving an SCG release without a CPC release from a network according to the prior art.

[0046] A method for handling UE stored CPC configuration upon SCG release event.

[0047] In the conventional method, such UE behavior has been captured in the specification of 3GPP TS 38.331v16.0.0, that is, when a UE (100) configured with CHO is sent to the RRC_INACTIVE state, that is, an RRC release message with a suspended configuration is sent to the CHO configured UE, which transitions the UE state from the RRC_CONNECTED state to the RRC_INACTIVE state. When the UE (100) with the stored CHO configuration receives the RRC release message, the UE (100) can autonomously release the CHO configuration when entering the RRC_INACTIVE state. However, the 3GPP specification does not discuss the handling of the CPC configuration when the SCG is released by the network. In addition, it has been agreed that the CPC configuration stored in the UE (100) is released upon a successful CPC execution or a successful regular PSCell change.

[0048] Similar to CHO, the CPC configuration and linked measurement configuration stored by the UE (100) are released upon successful CPC execution or successful completion of a regular PSCell change. The conditional configuration stored by the UE (100) is also released upon entering the RRC IDLE or RRC_INACTIVE state. However, with respect to RAN2, the handling of the CPC configuration stored by the UE (100) upon an SCG release event is not discussed in the 3GPP specifications.

[0049] CPC configuration is limited to intra-SN conditional PSCell changes and is configured by the SN to the UE (100) without MN involvement. When the SCG is released, the UE (100) resets the SCG Media Access Control (MAC), releases all Radio Link Control (RLC) entities on the SCG, and releases the SCG bearers. Only the radio bearer configuration may remain. The UE (100) is now only connected to the MCG, and the radio bearers can be released or reconfigured by the MCG. In such a state, the stored CPC configuration has no benefit.

[0050] As specified in the current 3GPP specification TS 38.331v16.0.0, when the SCG is released, the CPC configuration stored in the UE (100) is retained and not released. This leads to a scenario where the UE (100) is no longer in multi-radio dual connectivity (MR-DC) but still maintains a conditional configuration for PSCell changes. Since simultaneous configuration of CHO and CPC cannot be provided to the UE (100), only one variable is defined for storing the conditional configuration. Therefore, the received configuration is stored in a common variable, i.e., the CPC and CHO configurations are stored in VarConditionalConfig. Therefore, if the stored CPC configuration is retained after the SCG is released, the received configuration will cause ambiguity to the UE (100). This may even cause the UE (100) to regard future CHO configurations from the MN (200) as invalid configurations because it already has the stored CPC configuration. Therefore, when the NR SCG is released, the CPC configuration stored by the UE (100) must be released. In addition, the measID (measurement ID) and reportConfig (report configuration) associated with the CPC configuration, as well as the measObject (measurement object) associated only with the CPC (such as Figure 2 ).

[0051] like Figure 1 As shown, at S102, an RRC connection is established between the UE (100) and the SN (300), and a dual connection (DC) connection is established between the UE (100) and the SN (300). At S104, the SN (300) sends a CPC candidate configuration to the MN (200). At S106, an RRC reconfiguration including a CPC configuration container and a CPC condition is shared between the UE (100) and the MN (200). At S108, the UE (100) receives the CPC configuration and the measurement configuration stored in VarConditionalConfig. At S110, an RRC reconfiguration with SCG release but no CPC release is shared between the UE (100) and the MN (200). At S112, the UE (100) maintains the stored CPC configuration and the associated measurement configuration. At S114, the UE (100) is connected only to the MN (200). At S116, since the CPC configuration is stored, there is ambiguity regarding the CHO configuration for the UE.

[0052] Figure 2 1 is a sequence diagram showing a method for a UE (100) to autonomously clear a stored CPC configuration and a corresponding measurement configuration when receiving an SCG release without a CPC release from a network according to an embodiment of the present disclosure.

[0053] At S202, an RRC connection is established between the UE (100) and the SN (300), and a DC connection is established between the UE (100) and the SN (300). At S204, the SN (300) sends a CPC candidate configuration to the MN (200). At S206, an RRC reconfiguration including a CPC configuration container and a CPC condition is shared between the UE (100) and the MN (200). At S208, the UE (100) receives the CPC configuration and the measurement configuration stored in VarConditionalConfig. At S210, an RRC reconfiguration with SCG release but no CPC release is shared between the UE (100) and the MN (200). At S212, the UE (100) autonomously releases the stored CPC and measurement configuration. At S214, the UE (100) is connected only to the MN (200). At S216, the UE (100) has no ambiguity about the CHO configuration.

[0054] In one example, when the SCG is released, the UE (100) autonomously releases the stored CPC configuration. In addition, when the SCG is released, the UE (100) may remove the measID and reportConfig associated with the CPC configuration, as well as the measObject(s) associated only with the CPC. The changes made to the specification to implement these embodiments are as follows.

[0055]

Table 1

[0056]

[0057]

[0058] Meanwhile, the above-mentioned operations of the UE are merely examples, and the present disclosure is not limited thereto. That is, some of the above-mentioned operations may be omitted or may be performed simultaneously.

[0059] Releasing a cell group means releasing only the lower layer configuration of the cell group, but not releasing RadioBearerConfig .

[0060] In addition, there are 2 configurations associated with CHO:

[0061] 1. Measurement configuration:

[0062] a. Measurement object,

[0063] b. Report configuration, and

[0064] c. The measurement ID that links the measurement object and the report configuration;

[0065] 2. Conditional configuration of each candidate cell.

[0066] Upon receiving the CHO / CPC configuration, the UE (100) stores an entry for each candidate cell. The entry is identified using the CHO id signaled by the BS. Each entry includes a candidate conditional configuration, and an associated measurement configuration.

[0067] Figure 3 An overview of a wireless communication system (300) according to an embodiment of the present disclosure is shown, in which a UE (100) autonomously removes a stored CPC configuration and a corresponding measurement configuration upon receiving an SCG release from an MN (200). The wireless communication system (1000) includes a UE (100) and a MN (200). The UE (100) may be, for example, but not limited to, a cellular phone, a smart phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, an Internet of Things (IoT), a virtual reality device, and an immersive system. The UE (100) includes a processor (110), a transceiver (120), a memory (130), and an event handle controller (140) based on SCG release. The processor (110) is coupled to the transceiver (120), the memory (130), and the event handle controller (140) based on SCG release.

[0068] The event handler controller (140) based on SCG release is configured to receive an RRC message indicating the release of the SC from the MN (200). In one embodiment, the MN (200) is one of an evolved UMTS terrestrial radio access network (E-UTRA) and an NR network. In response to receiving the RRC message indicating the release of the SCG, the event handler controller (140) based on SCG release is configured to release the stored CPC configuration and the variables storing the CPC configuration. In one embodiment, the release of the SCG is received without the network explicitly requesting the UE (100) to release the stored CPC configuration. In one embodiment, the stored CPC configuration and the variables storing the CPC configuration are autonomously released on the UE (100).

[0069] In one embodiment, the SCG release based event handler controller (140) is configured to detect a measurement identifier associated with a stored CPC configuration and remove the measurement identifier associated with the stored CPC configuration in response to releasing the stored CPC configuration.

[0070] In another embodiment, for each measurement identifier configured for a source special cell (SpCell), an SCG release based event handler controller (140) is configured to determine whether a reporting configuration has a reporting type set as a conditional trigger configuration and remove the reporting configuration with a matching reporting configuration identifier from a reporting configuration list within VarMeasConfig for the reporting configuration identifier.

[0071] In another embodiment, the SCG release based event handler controller (140) is configured to remove the measurement object with the matching measurement object identifier (measObjectId) from the measurement object list (measObjectList) within VarMeasConfig if the measObjectId is associated only with a report configuration (reportConfig) having a report type set to a conditional trigger configuration (condTriggerConfig). The measurement object may be, for example, but not limited to, a frequency to be monitored, a cell list to be monitored, cell information, and frequency offset information.

[0072] In another embodiment, the SCG release based event handler controller (140) is configured to remove the measurement identifier with the matching measurement identifier from the measurement identifier list within VarMeasConfig.

[0073] In another embodiment, the SCG release based event handler controller (140) is configured to release the measurement objects associated with the CPC in response to releasing the stored CPC configuration.

[0074] The processor (110) is configured to execute instructions stored in the memory (130) and perform various processes. The transceiver (120) is configured to communicate internally between internal hardware components and to communicate with external devices via one or more networks. The memory (130) also stores instructions to be executed by the processor (110). The memory (130) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or an electrically programmable memory (EPROM) or an electrically erasable programmable (EEPROM) memory. In addition, in some examples, the memory (130) may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier or propagated signal. However, the term "non-transitory" should not be interpreted as the memory (130) being non-removable. In some examples, the non-transitory storage medium may store data that can change over time (e.g., in a random access memory (RAM) or a cache).

[0075] Although Figure 3 Various hardware components of the UE (100) are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments, the UE (100) may include fewer or more components. In addition, the labels or names of the components are for illustrative purposes only and do not limit the scope of the present disclosure. One or more components may be combined together to perform the same or substantially similar functions to process conditional configurations stored in the UE (100).

[0076] FIG. 4A to FIG. 4C is a flow chart (S400) showing a method for autonomously removing stored CPC configuration and corresponding measurement configuration upon receiving SCG release from MN according to an embodiment of the present disclosure. Operations (S402-S418) are performed by an event handler controller (140) based on SCG release.

[0077] At S402, the method includes receiving an RRC message indicating release of the SCG from the MN (200). At S404, the method includes releasing the stored CPC configuration and the variable storing the CPC configuration in response to receiving the RRC message indicating release of the SCG.

[0078] In one embodiment, at S406, the method includes removing the measurement object with the matching measurement object identifier from the measurement object list within VarMeasConfig if the measObjectId is only associated with a report configuration having a report type set as a conditional trigger configuration.

[0079] In another embodiment, at S408, the method includes removing the measurement identifier having the matching measurement identifier from the measurement identifier list in VarMeasConfig.

[0080] In another embodiment, at S410 , the method includes releasing the measurement object associated with the CPC in response to releasing the stored CPC configuration.

[0081] In another embodiment, at S412, the method includes detecting a measurement identifier associated with the stored CPC configuration.At S414, the method includes removing at least one measurement identifier associated with the stored CPC configuration in response to releasing the stored CPC configuration.

[0082] In another embodiment, at S416, the method includes, for each measurement identifier of the source special cell (SpCell) configuration, determining whether the report configuration has a report type set as a conditional trigger configuration. At S418, the method includes, for the report configuration identifier, removing the report configuration with a matching report configuration identifier from the report configuration list in VarMeasConfig.

[0083] The various activities, actions, blocks, steps, etc. in the flowchart (S400) may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, some activities, actions, blocks, steps, etc. may be omitted, added, modified, skipped, etc. without departing from the scope of the present disclosure.

[0084] Method for performing CHO failure recovery: In CHO, the UE (100) may be configured with attemptCondReconfig-r16. If a CHO failure occurs, or a normal handover failure occurs or a radio link failure is detected for the UE (100) configured with attemptCondReconfig-r160, if the cell selected for recovery at T311 operation belongs to the configured CHO candidate cell, CHO is triggered to the selected cell. Otherwise, RRC reestablishment is triggered.

[0085] Furthermore, there are also cases where the UE (100) in NR-DC is configured to perform fast MCG recovery when RLF is detected or PCell handover fails. When configured, the UE (100) sends an MCG Failure Information message via the SCG to indicate the failure on the MCG to the network. Therefore, if the UE (100) is configured with both MCG Failure Recovery and attemptCondReconfig-r16, there may be a conflict between which procedure to perform.

[0086] One approach is to restrict the network from providing these two configurations to the UE (100). Since it is the same network node, i.e., the MN (200), that provides these configurations to the UE (100), the MN (200) can ensure that both are not configured for the UE (100) at the same time. However, this is in network control, and if both are configured on the UE (100) at the same time, a mechanism must be defined on the UE (100). In one embodiment, CHO-based recovery is prioritized and the UE (100) performs CHO on the selected cell. In this method, MCG recovery using the MCG failure information message is not initiated at all. On the other hand, if the selected cell belongs to the list of candidate cells configured for CHO, the UE (100) is checked. If the selected cell is part of the CHO configuration, CHO is performed, i.e., CHO-based recovery is performed. Otherwise, MCG failure recovery is performed, i.e., if the selected cell is not a configured CHO candidate, MCG failure information is sent to the SCG.

[0087] Method for performing multiple CPC attempts before failure declaration: In most cases, the UE (100) will be configured with more than one candidate target cell for CPC. In addition to T310 expiration, i.e., RLF, other common failures for PSCell changes include T304 expiration. The UE (100) initiates CPC execution when the execution conditions for the CPC target cell are met. Starting T304, the UE RF tunes to the candidate target cell frequency and acquires the cell. In order to send the RRC reconfiguration complete message, random access is initiated. If the random access is not successful until T304 expires, failure is declared.

[0088] Since there is more than one candidate cell configured for the UE (100), all of which belong to the same gNB (i.e., cells within the SN), it is likely that other candidate cells also meet the CPC execution conditions. In one embodiment, the UE (100) attempts CPC execution on all candidate cells that meet the execution conditions. If CPC execution fails for all of these candidate cells, SCG failure is declared. If CPC execution is successful for any of these cells, the UE (100) successfully completes CPC and releases the stored CPC configuration and linked measurement configuration.

[0089] The UE (100) attempts random access to the candidate cell until T304 expires. However, there is also a maximum number of preamble transmissions configured for the UE (100). In one embodiment, the UE (100) attempts random access to CPC to the candidate cell only for the maximum number of preamble attempts configured for the UE (100). If random access fails, but T304 is still running, the UE (100) attempts CHO execution on the next cell, and so on. SCG failure is declared only when T304 expires, not when access to the first cell fails.

[0090] In another embodiment, a method may be used to handle conditional failures. The method includes checking, by the UE, whether the selected cell belongs to a list of candidate cells configured for CHO. If the selected cell is part of the CHO configuration, CHO is performed, i.e., CHO-based recovery is performed. Otherwise, MCG failure recovery is performed, i.e., if the selected cell is not a configured CHO candidate, MCG failure information is sent to the SCG.

[0091] In another embodiment, a method may be used to perform multiple CPC attempts before declaring SCG failure. The method includes the UE (100) attempting CPC on all candidate cells that have met the execution conditions. If CPC execution fails for all of these candidate cells, SCG failure is declared. If CPC execution is successful for any of these cells, the UE (100) successfully completes CPC and releases the stored CPC configuration and linked measurement configuration. The method also includes the UE (100) attempting random access to CPC on the candidate cells only for the maximum number of preamble code attempts configured for the UE. If random access fails, but T304 is still running, the UE attempts CHO execution on the next cell, and so on. SCG failure is declared only when T304 expires, rather than when access to the first cell fails.

[0092] The method can be used to prioritize CHO-based failure recovery over fast MCG recovery. If the cell selected after MCG failure is a CHO candidate cell, the method can be used to perform CHO, otherwise perform MCG failure recovery. The method can be used to attempt CHO execution on all candidate cells that have met the execution conditions. If access to all cells fails, SCG failure is declared. When the maximum preamble code attempt on the selected candidate fails and T304 is still running, the method can be used to attempt CPC execution on another candidate that meets the execution conditions.

[0093] Figure 5 A UE according to an embodiment of the present disclosure is shown.

[0094] Reference Figure 5 UE (500) may include a processor (510), a transceiver (520), and a memory (530). However, not all of the components shown are required. UE (500) may include a processor (510), a transceiver (520), and a memory (530). Figure 5 The components shown may be implemented with more or fewer components. In addition, according to another embodiment, the processor (510) and the transceiver (520) and the memory (530) may be implemented as a single chip.

[0095] The UE (500) may correspond to the above-mentioned UE.

[0096] The above-mentioned components will now be described in detail.

[0097] The processor (510) may include one or more processors or other processing devices that control the provided functions, processes and / or methods. The operation of the UE (500) may be implemented by the processor (510). According to an embodiment of the present disclosure, the processor (510) may control the signal flow between each block to perform the provided functions, processes and / or methods.

[0098] The transceiver (520) may include an RF transmitter for up-converting and amplifying transmitted signals, and an RF receiver for down-converting the frequency of received signals. However, according to another embodiment, the transceiver (520) may be implemented by more or fewer components than shown in the components.

[0099] The transceiver (520) may be connected to the processor (510) and transmit and / or receive signals. The signals may include control information and data. In addition, the transceiver (520) may receive signals through a wireless channel and output the signals to the processor (510). The transceiver (520) may transmit signals output from the processor (510) through a wireless channel.

[0100] The memory (530) may store control information or data included in a signal obtained by the UE (500). The memory (530) may be connected to the processor (510) and store at least one instruction or protocol or parameter for the provided functions, processes and / or methods. The memory (530) may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0101] Figure 6 A base station according to an embodiment of the present disclosure is shown.

[0102] Reference Figure 6 , the base station (600) may include a processor (610), a transceiver (620), and a memory (630). However, all of the components shown are not required. The base station (600) may include a processor (610), a transceiver (620), and a memory (630). Figure 6 The components shown may be implemented with more or fewer components. In addition, according to another embodiment, the processor (610) and the transceiver (620) and the memory (630) may be implemented as a single chip.

[0103] The base station (600) may correspond to an MN or a SN according to an embodiment of the present disclosure.

[0104] The above-mentioned components will now be described in detail.

[0105] The processor (610) may include one or more processors or other processing devices that control the functions, processes and / or methods provided. The operations of the base station (600) may be implemented by the processor (610). According to an embodiment of the present disclosure, the processor (610) may control the signal flow between each block to perform the functions, processes and / or methods provided.

[0106] The transceiver (620) may include an RF transmitter for up-converting and amplifying transmitted signals, and an RF receiver for down-converting the frequency of received signals. However, according to another embodiment, the transceiver (620) may be implemented by more or fewer components than shown in the components.

[0107] The transceiver (620) may be connected to the processor (610) and transmit and / or receive signals. The signals may include control information and data. In addition, the transceiver (620) may receive signals through a wireless channel and output the signals to the processor (610). The transceiver (620) may transmit signals output from the processor (610) through a wireless channel.

[0108] The memory (630) may store control information or data included in a signal obtained by the base station (600). The memory (630) may be connected to the processor (610) and store at least one instruction or protocol or parameter for the provided functions, processes and / or methods. The memory (630) may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0109] The embodiments of the present disclosure are applicable to LTE, NR and other cellular communication technologies. Reference to any one of these technologies in the present disclosure is for illustrative purposes only and is not limited thereto.

[0110] The above description of the specific embodiments will fully reveal the general nature of the embodiments herein, so that others can easily modify and / or adapt various applications such as the specific embodiments by applying current knowledge without departing from the general concept, and therefore, such adaptations and modifications should and are intended to be understood as being within the equivalent meaning and scope of the disclosed embodiments. It should be understood that the words or terms used herein are for the purpose of description rather than limitation. Therefore, although the embodiments herein have been described in accordance with the preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.

[0111] Although the present disclosure has been described by various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method performed by a user equipment UE in a communication system, the method comprising: Receiving, from a first base station associated with a primary cell group MCG, a first message for configuring a second base station associated with a secondary cell group SCG; receiving from the second base station a second message including a conditional primary and secondary cell (PSCell) CPC configuration change, wherein the CPC configuration includes at least one configuration for at least one candidate PSCell and at least one condition for triggering CPC execution for each of the at least one candidate PSCell; storing the CPC configuration; as well as In case a third message for releasing the SCG of the second base station is received from the first base station, the stored CPC configuration is removed.

2. The method according to claim 1, wherein: Each of the at least one condition includes at least one measurement identifier ID associated with at least one measurement object and at least one reporting configuration.

3. The method according to claim 1, wherein: The first base station is associated with at least one of a New Radio (NR) network and an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and wherein the second base station is associated with the NR network.

4. The method according to claim 1, wherein: The secondary cell group includes zero or more secondary cells and a PSCell of the second base station.

5. The method of claim 1, further comprising, in a case where the CPC configuration is stored in the UE, skipping storing a conditional handover (CHO) configuration.

6. The method according to claim 1, wherein: The second message is received via radio resource control (RRC) signaling without involving the first base station.

7. A user equipment (UE) in a communication system, the UE comprising: Transceiver; as well as A controller is coupled to the transceiver and is configured to: receiving, from a first base station associated with a primary cell group MCG, a first message for configuring a second base station associated with a secondary cell group SCG, receiving from the second base station a second message including a conditional primary and secondary cell (PSCell) CPC configuration change, wherein the CPC configuration includes at least one configuration for at least one candidate PSCell and at least one condition for triggering CPC execution for each of the at least one candidate PSCell, storing the CPC configuration; as well as In case a third message for releasing the SCG of the second base station is received from the first base station, the stored CPC configuration is removed.

8. The UE according to claim 7, wherein: Each of the at least one condition includes at least one measurement identifier ID associated with at least one measurement object and at least one reporting configuration.

9. The UE according to claim 7, wherein: The first base station is associated with at least one of a New Radio (NR) network or an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and wherein the second base station is associated with the NR network.

10. The UE according to claim 7, wherein: The secondary cell group includes zero or more secondary cells and a PSCell of the second base station. 11 . The UE according to claim 7 , wherein the controller is further configured to, in a case where the CPC configuration is stored in the UE, skip storing a conditional handover (CHO) configuration.

12. The UE according to claim 7, wherein: The second message is received via Radio Resource Control (RRC) signaling without involving the first base station.

Images