Method and apparatus for retransmitting qoe measurement report in wireless communication system

Abstract

The present invention relates to a method comprising the steps of: receiving a radio resource control (RRC) message, the RRC message including at least one quality of experience (QoE) measurement configuration that includes information about a signaling radio bearer (SRB) to report a result of a QoE measurement, and / or information that indicates whether a RRC segmentation for a QoE measurement report message including the result of the QoE measurement in a changed cell group is allowed; identifying, on the basis of the reception of the RRC message, whether the transmission of the QoE measurement report message has been checked for success, the QoE measurement report message transmission being based on the configured SRB; identifying whether the RRC segmentation for the QoE measurement report message has been used, if it has not been checked whether the transmission of the QoE measurement report message is successful; and transmitting all segments of the QoE measurement report message on the basis of the SRB to report the result of the QoE measurement if the RRC segmentation for the QoE measurement report message has been used and the RRC segmentation for the QoE measurement report message is allowed in the changed cell group.

Description

Method and device for retransmitting QOE measurement report in wireless communication system

[0001] The present invention relates to the operation of a terminal and a base station in a wireless communication system. More specifically, the present invention relates to a method and device for retransmitting a QoE measurement report in a wireless communication system.

[0002] 5G (5th generation) mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G (6th generation) mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] The disclosed embodiment seeks to provide a method and device capable of effectively providing a service in a mobile communication system.

[0009] The present disclosure aims to retransmit QoE measurement reports.

[0010] The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0011] Based on the discussion described above, the present disclosure provides a method for processing a control signal in a mobile communication system, which may include: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

[0012] Specifically, according to one embodiment of the present invention, a method performed by a terminal in a communication system, the method comprising: receiving a radio resource control (RRC) message, wherein the RRC message includes at least one of: at least one QoE measurement configuration including information on a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement; and information indicating whether RRC segmentation for a QoE measurement report message including a result of the QoE measurement is allowed in a changed cell group; identifying, based on reception of the RRC message, whether successful transmission of the QoE measurement report message has been confirmed, wherein transmission of the QoE measurement report message is based on a configured SRB; identifying, when successful transmission of the QoE measurement report message has not been confirmed, whether RRC segmentation for the QoE measurement report message has been used; And, if RRC segmentation for the QoE measurement report message is used and if the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, a method is proposed characterized by including a step of transmitting all segments of the QoE measurement report message based on an SRB to which the result of the QoE measurement is to be reported.

[0013] In addition, according to one embodiment of the present invention, a method performed by a base station in a communication system comprises the steps of: transmitting a radio resource control (RRC) message to a terminal, the RRC message including at least one QoE measurement configuration including information on a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group; And a step of receiving a message about completion of cell group change from the terminal; wherein, if transmission of the QoE measurement report message by the terminal is not successfully performed based on an SRB set, RRC segmentation for the QoE measurement report message is used, and the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, a method is proposed characterized in that all segments of the QoE measurement report message are transmitted to the changed cell group based on an SRB to which the result of the QoE measurement is to be reported.

[0014] In addition, according to one embodiment of the present invention, in a terminal of a communication system, the terminal comprises a transceiver; And a control unit connected to the transceiver, wherein the control unit: receives a radio resource control (RRC) message, wherein the RRC message includes at least one QoE measurement configuration including information on a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement and information indicating whether RRC segmentation for a QoE measurement report message including a result of the QoE measurement is allowed in a changed cell group, and based on reception of the RRC message, identifies whether the transmission of the QoE measurement report message is confirmed to be successful, and transmission of the QoE measurement report message is based on a set SRB, and when the transmission of the QoE measurement report message is not confirmed to be successful, identifies whether RRC segmentation for the QoE measurement report message is used, and when RRC segmentation for the QoE measurement report message is used and when the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, reports the result of the QoE measurement. We propose a terminal characterized by transmitting all segments of the above QoE measurement report message based on SRB.

[0015] In addition, according to one embodiment of the present invention, in a base station of a communication system, the base station comprises: a transceiver; And a control unit connected to the transceiver, wherein the control unit: transmits, to a terminal, a radio resource control (RRC) message, wherein the RRC message includes at least one QoE measurement configuration including information on a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group, and receives, from the terminal, a message regarding completion of a cell group change, and when transmission of the QoE measurement report message by the terminal is not successfully performed based on a configured SRB, RRC segmentation for the QoE measurement report message is used, and the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, all segments of the QoE measurement report message are transmitted to the changed cell group based on the SRB to report the result of the QoE measurement.

[0016] The disclosed embodiments provide a device and method for effectively providing services in a mobile communication system. Specifically, the present disclosure provides a device and method capable of retransmitting a QoE measurement report.

[0017] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0018] FIG. 1a is a diagram illustrating the structure of a mobile communication system according to one embodiment of the present disclosure.

[0019] FIG. 1b is a diagram illustrating a wireless connection state transition in a mobile communication system according to an embodiment of the present disclosure.

[0020] FIG. 1c is a diagram illustrating a procedure for setting up and / or reporting signaling-based quality of experience (QoE) measurements according to one embodiment of the present disclosure.

[0021] FIG. 1d is a diagram illustrating a procedure for setting up and / or reporting management-based QoE measurements according to one embodiment of the present disclosure.

[0022] FIG. 1e is a diagram illustrating a procedure for setting up and / or reporting radio access network (RAN) visible QoE measurements according to one embodiment of the present disclosure.

[0023] FIG. 1f is a diagram illustrating a procedure for retransmitting a QoE measurement report when a terminal performs a handover according to an embodiment of the present disclosure.

[0024] FIG. 1g is a diagram illustrating a procedure for retransmitting a QoE measurement report when a terminal performs a handover (MN (master node) change) or SN (secondary node) change according to one embodiment of the present disclosure.

[0025] FIG. 1h is a diagram illustrating a procedure for retransmitting a QoE measurement report according to a configured SRB (signaling radio bearer) when a terminal performs a handover according to an embodiment of the present disclosure.

[0026] FIG. 1i is a diagram illustrating a procedure for retransmitting a QoE measurement report depending on whether a new base station allows RRC (radio resource control) segmentation when a terminal performs a handover according to one embodiment of the present disclosure.

[0027] FIG. 1ja is a diagram illustrating a procedure for retransmitting a QoE measurement report according to whether the configured SRB and the RRC segmentation of the new base station are permitted when a terminal performs a handover (MN change) or SN change according to one embodiment of the present disclosure.

[0028] FIG. 1jb is a diagram illustrating a procedure for retransmitting a QoE measurement report according to whether the configured SRB and the RRC segmentation of the new base station are permitted when a terminal performs a handover (MN change) or SN change according to one embodiment of the present disclosure.

[0029] FIG. 1k is a diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0030] FIG. 1l is a diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0031] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0032] The various embodiments of the present disclosure described below may illustrate a hardware-based approach. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0033] In the following description, terms referring to components of the device (control unit, processor, artificial intelligence (AI) model, encoder, decoder, autoencoder (AE), neural network (NN) model, etc.) and terms referring to data (signal, feedback, report, reporting, information, parameter, value, bit, codeword, etc.) are examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0034] Additionally, while this disclosure describes various embodiments using terminology used in certain communication standards (e.g., 3rd Generation Partnership Project (3GPP)), these are merely illustrative examples. The various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0035] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. It should be noted that, where possible, identical components are represented by identical reference numerals in the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted. In describing the embodiments, descriptions of technical details that are well-known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure may be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0036] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0037] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the present disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals may refer to like elements throughout the specification.

[0038] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment can create a means for performing the functions described in the flow diagram block(s).

[0039] These computer program instructions may also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing device to implement a function in a particular manner, so that the instructions stored in the computer-available or computer-readable memory can also produce an article of manufacture that includes instruction means for performing the function described in the flowchart block(s).

[0040] Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0041] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0042] Here, the term "~unit" used in this embodiment refers to software or hardware components such as FPGAs or ASICs, and the "~unit" can perform certain roles. However, the "~unit" is not limited to software or hardware. The "~unit" may be configured to reside on an addressable storage medium or may be configured to play one or more processors.

[0043] Thus, as an example, '~bu' may include components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.

[0044] The functionality provided within the components and '~sub-units' may be combined into a smaller number of components and '~sub-units' or further separated into additional components and '~sub-units'. Furthermore, the components and '~sub-units' may be implemented to activate one or more CPUs within the device or secure multimedia card. Furthermore, in an embodiment, the '~sub-unit' may include one or more processors.

[0045] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0046] For convenience of explanation, this disclosure uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP) LTE (Long Term Evolution) standard or the New Radio (NR) standard. However, this disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards.

[0047] Hereinafter, a base station (BS) is an entity that performs resource allocation of a terminal, and may be at least one of a radio access network (RAN) node, a next generation node B (gNB), an evolved node B (eNB), a Node B, a wireless access unit, a base station controller, or a node on a network. In the present disclosure, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as an eNB may represent a gNB.

[0048] Hereinafter, a terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Of course, the above examples are not limited thereto.

[0049] In particular, the present disclosure is applicable to 3GPP NR (the 5th generation mobile communications standard). Furthermore, the present disclosure may be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, healthcare, digital education, retail, security, and safety-related services) based on 5G communication technology and IoT (Internet of Things)-related technologies. Furthermore, the term "terminal" may refer to not only mobile phones, NB-IoT devices, and sensors, but also other wireless communication devices.

[0050] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e.

[0051] As a representative example of a broadband wireless communication system, the LTE system adopts the OFDM (Orthogonal Frequency Division Multiplexing) method in the downlink (DL) and the SC-FDMA (Single Carrier Frequency Division Multiple Access) method in the uplink (UL). The uplink refers to a wireless link in which a terminal (or UE) transmits data or control signals to a base station (or eNB, gNB), and the downlink refers to a wireless link in which a base station transmits data or control signals to a terminal. The above multiple access method distinguishes the data or control information of each user by allocating and operating the time-frequency resources to be transmitted to each user so that they do not overlap, that is, so as to achieve orthogonality.

[0052] As a future communications system beyond LTE, 5G communications systems must be able to freely reflect the diverse needs of users and service providers. Therefore, they must support services that simultaneously satisfy these diverse requirements. Services being considered for 5G communications systems include enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable low-latency communications (URLLC).

[0053] In one embodiment, eMBB may aim to provide data transmission rates that are significantly higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB should be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. Furthermore, a 5G communication system may need to provide both the peak data rate and the increased user-perceived data rate of a terminal. To meet these requirements, a 5G communication system may require improvements in various transmission and reception technologies, including improved multiple-input multiple-output (MIMO) transmission technology. Furthermore, while current LTE transmits signals using a maximum 20 MHz transmission bandwidth in the 2 GHz band, a 5G communication system can use a wider frequency bandwidth than 20 MHz in the 3-6 GHz or higher 6 GHz band, thereby meeting the data transmission rates required by the 5G communication system.

[0054] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the IoT, mMTC may require support for large-scale terminal connections within a cell, improved terminal coverage, improved battery life, and reduced terminal costs. The IoT requires the ability to support a large number of terminals (e.g., 1,000,000 terminals / km^2) within a cell, as it provides communication capabilities through the attachment of various sensors and devices. Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in shadow areas not covered by cells, such as basements, which may require wider coverage than other services provided by 5G communication systems. Terminals supporting mMTC should be comprised of low-cost terminals, and since frequent battery replacement is unlikely, very long battery lifespans, such as 10 to 15 years, may be required.

[0055] Finally, URLLC is a cellular-based wireless communication service used for specific purposes (mission-critical), such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles (UAVs), remote health care, and emergency alerts. Therefore, the communication provided by URLLC may need to provide very low latency (ultra-low latency) and very high reliability (ultra-reliability). For example, a service supporting URLLC may have to satisfy an air interface latency of less than 0.5 milliseconds and may also have a requirement of a packet error rate (PER) of 10^-5 or less. Therefore, for services supporting URLLC, 5G systems may be required to provide a smaller transmission time interval (TTI) than other services, while simultaneously allocating a wide range of resources in the frequency band to ensure the reliability of the communication link.

[0056] The three services considered in the aforementioned 5G communication system—eMBB, URLLC, and mMTC—can be multiplexed and transmitted in a single system. To meet the differing requirements of each service, different transmission and reception techniques and parameters may be used between services. However, the aforementioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types applicable to this disclosure are not limited to the aforementioned examples.

[0057] Furthermore, although embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro, 5G (or NR), or 6G systems as examples, the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0058] FIG. 1a is a diagram illustrating the structure of a mobile communication system according to one embodiment of the present disclosure.

[0059] Referring to FIG. 1a, a wireless access network of a mobile communication system (New Radio, NR) according to an embodiment of the present disclosure may be composed of a base station (next generation Node B, hereinafter referred to as gNB) (1a-10) and an access and mobility management function (AMF) (1a-05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1a-15) may access an external network through the gNB (1a-10) and the AMF (1a-05). The mobile communication system according to an embodiment of the present disclosure may be a next generation mobile communication system, and the base station may be a next generation base station.

[0060] In Fig. 1a, the gNB corresponds to the eNB (Evolved Node B) of the existing LTE system. The gNB is connected to the NR UE via a wireless channel and can provide a service superior to the existing Node B (1a-20). In the next-generation mobile communication system according to an embodiment of the present disclosure, since all user traffic is serviced through a shared channel, a device that collects status information such as the buffer status of UEs, available transmission power status, and channel status and performs scheduling is required, and this is handled by the gNB (1a-10). A single gNB can typically control multiple cells. In order to implement ultra-high-speed data transmission compared to the existing LTE, it can have a bandwidth higher than the existing maximum, and beamforming technology can be additionally grafted using the orthogonal frequency division multiplexing (OFDM) scheme as a wireless access technology. Additionally, an adaptive modulation and coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel status of the terminal can be applied.

[0061] AMF (1a-05) can perform functions such as mobility support, bearer setup, and QoS (quality of service) setup. AMF is a device that is responsible for various control functions as well as mobility management functions for terminals and can be connected to multiple base stations. In addition, a mobile communication system according to an embodiment of the present disclosure can be interoperable with an existing LTE system, and AMF can be connected to a mobility management function (MME) (1a-25) through a network interface. MME is connected to an existing base station, eNB (1a-30). A terminal that supports LTE-NR Dual Connectivity can transmit and receive data while maintaining a connection to not only a gNB but also an eNB (1a-35).

[0062] FIG. 1b is a diagram illustrating a wireless connection state transition in a mobile communication system according to an embodiment of the present disclosure.

[0063] A mobile communication system according to an embodiment of the present disclosure may have three types of radio connection states (RRC states) or RRC modes. The connected mode (RRC_CONNECTED, 1b-05) is a radio connection state in which a terminal can transmit and receive data. The idle mode (RRC_IDLE, 1b-30) is a radio connection state in which a terminal monitors whether paging is transmitted to itself. The connected mode or idle mode is a radio connection state that is also applied to the existing LTE system, and the detailed technology may be the same as that of the existing LTE system. The mobile communication system according to an embodiment of the present disclosure may be a next-generation mobile communication system.

[0064] In a mobile communication system according to an embodiment of the present disclosure, a new inactive (RRC_INACTIVE) radio connection state (1b-15) is defined. In this radio connection state, UE context is maintained between the base station and the terminal, and RAN (radio access network)-based paging can be supported. The characteristics of this new radio connection state are listed below.

[0065] - Cell re-selection mobility;

[0066] - CN (core network) - NR RAN connection (both C / U-planes (control plane / user plane)) has been established for UE;

[0067] - The UE AS (Access Stratum) context is stored in at least one gNB and the UE;

[0068] - Paging is initiated by NR RAN;

[0069] - RAN-based notification area is managed by NR RAN;

[0070] - NR RAN knows the RAN-based notification area which the UE belongs to;

[0071] According to one embodiment of the present disclosure, a terminal in an INACTIVE wireless connection state can transition to a connected mode or a standby mode using a specific procedure. The terminal can transition from INACTIVE mode to a connected mode through a Resume procedure, and can transition from a connected mode to INACTIVE mode through a Release procedure including suspend configuration information (1b-10). The procedure is performed by transmitting and receiving one or more RRC messages between the terminal and a base station, and can consist of one or more steps. In addition, transition from INACTIVE mode to standby mode is possible through a Release procedure after Resume (1b-20). The transition between the connected mode and the standby mode can follow the existing LTE technology. That is, the transition between the modes can be achieved through an establishment or release procedure (1b-25).

[0072] FIG. 1c is a diagram illustrating a procedure for setting and / or reporting signaling-based quality of experience (QoE) measurement according to one embodiment of the present disclosure.

[0073] In the embodiment of FIG. 1c, the UE AS (access stratum) (1c-05) may be defined as a terminal, and the NG-RAN (1c-15) may be defined as a base station. The UE AS may be defined as the AS layer of the terminal, and the UE APP (1c-45) may be defined as the terminal application layer. Operations performed by the UE AS and the UE APP may be interpreted as operations performed by the terminal.

[0074] Referring to FIG. 1c, in step 1c-10, the UE AS may transmit capability information to the NG RAN. The UE AS (1c-05) may transmit information (e.g., qoe-Streaming-MeasReport, qoe-MTSI-MeasReport, qoe-VR-MeasReport) indicating whether QoE measurement is supported by service type (e.g., streaming, MTSI (multimedia telephony service for IMS (IP (internet protocol) multimedia subsystem)), VR (virtual reality)) to the base station (or NG-RAN, 1c-15) via a UE capability message (e.g., UECapabilityInformation). Before the terminal transmits the UE capability message to the base station, the base station may transmit a message (e.g., UECapabilityEnquiry) to the terminal for requesting the UE capability message. In addition, the terminal can report to the base station whether it supports RAN visible QoE measurement by service type (e.g., streaming, VR) through the UE capability message (e.g., ran-VisibleQoE-Streaming-MeasReport, ran-VisibleQoE-VR-MeasReport). In addition, the terminal can report to the base station whether it supports UL RRC segmentation for QoE report message (e.g., ul-MeasurementReportAppLayer-Seg) through the UE capability message. The UE capability message can include ASN.1 (abstract syntax notation one) information as shown in Table 1 below.A description of the relevant parameters (e.g., QoE measurement parameters) may be as shown in Table 2 below.

[0075] [Table 1]

[0076]

[0077] [Table 2]

[0078]

[0079] The types of services supported in LTE may include at least one of streaming or MTSI. In the case of NR, in addition to the types of services supported in LTE, support for VR services was defined in Rel-17, and it was defined that additional services such as MBMS (multimedia broadcast multicast services) and XR (extended reality) may be supported in future releases. The services supported in NR systems are not limited to the examples above.

[0080] In step 1c-30, the operations administration and maintenance (OAM, 1c-20) can configure QoE measurement to the core network (CN, 1c-25). The OAM can provide or transmit QoE measurement configuration information (e.g., QoE measurement configuration) to the CN (1c-30).

[0081] The CN (1c-25) that has received QoE measurement configuration information can activate QoE measurement in step 1c-35. The CN can activate QoE measurement by transmitting the QoE measurement configuration information to the base station (1c-15) (1c-35).

[0082] The base station (1c-15) may transmit or forward QoE configuration information to the UE AS (1c-05) via an RRC message (e.g., an RRCReconfiguration or RRCResume message) in step 1c-40. The RRC message may include an information element (IE) (e.g., APPLayerMeasConfig) as shown in Table 3 below. The description of the related parameters may be as shown in Table 4 below.

[0083] [Table 3]

[0084]

[0085] [Table 4]

[0086]

[0087] According to one embodiment of the present disclosure, the operation of a terminal AS (1c-05) that receives QoE setting information from a base station via an RRC message may be as shown in Table 5 below.

[0088] [Table 5]

[0089]

[0090]

[0091] The UE AS (1c-05) may provide or transmit QoE measurement configuration information to the UE APP (1c-45) in step 1c-50. At this time, the UE AS may use an AT command. For the QoE measurement configuration included in measConfigAppLayerToAddModList, the UE AS (1c-05) may transmit part or all of the QoE measurement configuration information to the upper layer or application layer (UE APP, 1c-45) of the terminal via an AT command (1c-50). In addition, the UE AS (1c-05) may send an AT command to the UE APP (1c-45) to instruct or command the UE to delete stored configuration information for the QoE measurement configuration included in measConfigAppLayerToAddReleaseList.

[0092] The UE APP (1c-45) can perform QoE measurement based on the received configuration information. In addition, the UE APP (1c-45) can report a QoE measurement report (e.g., QoE report) including the measurement results based on the configuration information in step 1c-55d to the UE AS (1c-05) via an AT command (1c-55).

[0093] The UE AS (1c-05) can report the QoE measurement results to the base station (1c-15) via an RRC message (e.g., a MeasurementReportAppLayer message) in step 1c-60 (1c-60). SRB (signaling radio bearer) 4 can be used to report the QoE measurement results. The MeasurementReportAppLayer message can include ASN.1 information as shown in Table 6 below. The description of the related parameters can be as shown in Table 7 below.

[0094] [Table 6]

[0095]

[0096]

[0097] [Table 7]

[0098]

[0099] The procedure of UE AS (1c-05) reporting QoE measurement results may be as shown in Table 8 below. In Table 8 below, UE corresponds to a terminal or UE AS (1c-05), and network corresponds to an NG-RAN or base station.

[0100] [Table 8]

[0101]

[0102]

[0103] The base station (1c-15) can transmit the measurement result report received from the terminal to the final server (TCE (trace collection entity) or MCE (measurement collection entity), 1c-65) that collects the measurement report in step 1c-70 (1c-70).

[0104] FIG. 1d is a diagram illustrating a procedure for setting up and / or reporting management-based QoE measurements according to one embodiment of the present disclosure.

[0105] In the embodiment of FIG. 1d, the UE AS (1d-05) may be defined as a terminal, and the NG-RAN (1d-50) may be defined as a base station. The UE AS (1d-05) may be defined as an AS layer of the terminal, and the UE APP (4-45) may be defined as a terminal application layer. The operations performed by the UE AS (4-05) and the UE APP (4-45) may be interpreted as operations performed by the terminal.

[0106] Referring to Fig. 1d, operations performed in the Management-based QoE configuration and / or reporting procedure may be similar to operations performed in the signaling-based QoE configuration and / or reporting procedure described in Fig. 1c. Therefore, among the operations of Fig. 1d, operations that are identical or similar to or overlapping with the operations of Fig. 1c may be omitted for separate description, and the omitted operations may refer to the description of 1c. In the present disclosure, the Management-based QoE configuration and / or reporting procedure is described, and only differences from the signaling-based procedure may be described.

[0107] The UE AS (1d-05) may transmit capability information to the NG-RAN (1d-50) at step 1d-40 (1d-10). The operation of 1d-10 and related operations refer to the operation of 1c-10 and related description of FIG. 1c.

[0108] OAM can activate QoE measurement by transmitting QoE measurement settings (e.g., QoE measurement configuration) to NG-RAN in step 1d-15. In this case, in a method related to management-based QoE settings and / or reporting procedures, OAM (1d-05) can directly transmit QoE measurement settings to the base station (1d-50) without going through the CN, thereby instructing the base station to activate QoE measurement of the terminal (1d-15).

[0109] The base station (1d-50) can search for a single or multiple terminals that meet at least one condition (e.g., at least one of area scope, application layer capability, and service type). The base station (1d-50) can transmit or forward QoE measurement settings to any one of the single or multiple terminals searched in step 1d-20. At this time, the base station can transmit or forward QoE measurement settings to the terminal via an RRC message (e.g., an RRCReconfiguration message or an RRCResume) (1d-20).

[0110] The terminal may transmit an AT command including QoE measurement settings to the UE APP in step 1d-30. The UE APP may perform measurements and transmit an AT command including the measurement results (e.g., QoE report) to the UE AS in step 1d-35. The UE AS may transmit an RRC message including the QoE report to the NG-RAN (1d-50). The NG-RAN may transmit the QoE report to the TCE or MCE in step 1d-45. For specific descriptions of 1d-30, 1d-35, 1d-40, and 1d-45, refer to the description of the corresponding operations in FIG. 1c.

[0111] FIG. 1e is a diagram illustrating a procedure for setting up and reporting radio access network (RAN) visible QoE measurements according to one embodiment of the present disclosure.

[0112] In the embodiment of FIG. 1e, the UE AS may be defined as a terminal, and the NG-RAN may be defined as a base station. The terminal AS may be defined as the terminal's AS layer, and the UE APP may be defined as the terminal application layer. The operations performed by the UE AS and the UE APP may be interpreted as operations performed by the terminal.

[0113] According to one embodiment of the present disclosure, when following the method related to the signaling-based QoE setting and / or reporting procedure in FIG. 1c or the Management-based QoE setting and / or reporting procedure in FIG. 1d, QoE measurement is set by OAM, and QoE measurement reports generated according to the QoE measurement settings are collected in TCE or MCE, and the QoE measurement reports can be used by operators for network optimization.

[0114] Base stations may have difficulty reading or understanding QoE measurement reports transmitted by terminals. MeasurementReportAppLayer messages can contain measurement reports generated by the terminal's application layer in the MeasurementReportAppLayerContainer . However, because they are stored in OCTEC STRING format, the base station or its RRC layer may have difficulty reading or understanding the QoE measurement reports.

[0115] To address the issue of difficulty in reading or understanding QoE measurement reports, 3GPP allows base stations to read QoE measurement reports from terminals and utilize the QoE measurement reports for network optimization, such as radio resource management, by using RAN visible QoE (RVQoE) measurements.

[0116] According to one embodiment of the present disclosure, RVQoE measurement may be defined to be limited to a specific service type (e.g., streaming or VR). The terminal may report information indicating whether RVQoE measurement is supported for each service type (e.g., streaming or VR) to the base station in step 1e-05. At this time, the UECapabilityInformation message may be used. For example, the terminal may include or set the ran-VisibleQoE-Streaming-MeasReport parameter in the UECapabilityInformation message and transmit it to the base station for a Streaming service, and may include or set the ran-VisibleQoE-VR-MeasReport parameter in the UECapabilityInformation message and transmit it to the base station for a VR service.

[0117] By including or setting a parameter indicating whether the terminal supports RVQoE measurement, the base station can determine whether the terminal supports RVQoE measurement for each service type. The base station can generate an RVQoE measurement configuration based on whether RVQoE measurement is supported. The base station can transmit RVQoE configuration information to the terminal in step 1e-10 (1e-10). At this time, the RVQoE measurement configuration can be transmitted together with the OAM-based QoE measurement configuration. The RVQoE measurement configuration can be included in an RRCReconfiguration or RRCResume message. For example, the base station can instruct the terminal to set up or release RVQoE measurement by setting or releasing the ran-VisibleParameters parameter in the AppLayerMeasConfig IE. The ran-VisibleParameters parameter can include the RAN-VisibleParameters IE. At least one of the following parameters can be provided from the base station to the terminal through this step.

[0118] - RVQoE measurement report period (e.g., ran-VisiblePeriodicity): UE AS or UE APP can send RVQoE measurement report to base station every RVQoE period.

[0119] - The maximum number of reportable buffer levels (e.g., numberOfBufferLevelEntries): When reporting RVQoE measurements, the UE AS or UE APP may include multiple buffer levels, and a number of buffer levels equal to or less than the value set as numberOfBufferLevelEntries may be included in the RVQoE measurement report.

[0120] - Whether to report playout delay at media start (e.g., reportPlayoutDelayForMediaStartup): If the value of reportPlayoutDelayForMediaStartup is indicated as true, the UE AS or UE APP can include the playout delay at media start in the RVQoE report and transmit it. If the value of reportPlayoutDelayForMediaStartup is indicated as false, the UE AS or UE APP may not include the playout delay at media start in the RVQoE report.

[0121] The UE AS may forward or transmit RVQoE configuration information to the UE APP in step 1e-15 (1e-15). The RVQoE configuration information may include the configuration information described above (for example, at least one of ran-VisiblePeriodicity, numberOfBufferLevelEntries, or reportPlayoutDelayForMediaStartup). The UE AS may forward or transmit RVQoE configuration information to the UE APP using an AT command. At this time, the RVQoE configuration information may be forwarded to the APP layer together with the OAM-based QoE measurement configuration. The UE APP may perform QoE measurement based on the RVQoE measurement configuration information, generate an RVQoE measurement report, and transmit the same to the UE AS in step 1e-20 (1e-20). The UE APP may transmit the RVQoE measurement report to the UE AS using an AT command. At this time, the RVQoE measurement report can be delivered to the AS layer together with the OAM-based QoE measurement report.

[0122] The UE AS may forward, transmit, or report the RVQoE measurement report to the base station at step 1e-25 (1e-25). The UE AS may forward, transmit, or report the RVQoE measurement report to the base station via an RRC message. At this time, the RVQoE measurement report may be forwarded, transmitted, or reported to the base station together with an OAM-based QoE measurement report. At step 1e-25, the RVQoE measurement report may be transmitted via a RAN-VisibleMeasurements IE in a MeasurementReportAppLayer message, and the RAN-VisibleMeasurements IE may include at least one of the following parameters.

[0123] - APP layer buffer level list (e.g., appLayerBufferLevelList): The terminal can include multiple buffer levels measured by the UE APP and report multiple buffer levels to the base station through appLayerBufferLevelList. The number of parameters included in the RVQoE configuration information may be limited by numberOfBufferLevelEntries.

[0124] - Playout delay (e.g., playoutDelayForMediaStartup): The terminal can include a playout delay when starting media and report the playout delay to the base station via playoutDelayForMediaStartup. The playout delay value can be indicated in ms. The terminal can include playoutDelayForMediaStartup in the RVQoE measurement report if reportPlayoutDelayForMediaStartup is set to true in the RVQoE configuration information.

[0125] - PDU session ID list (e.g., pdu-SessionIdList): The terminal can indicate to the base station the PDU (Protocol Data Unit) session(s) used in the application data flow that is the target of RVQoE measurement through pdu-SessionIdList. The base station can identify for which PDU session(s) the RVQoE values ​​(e.g., buffer level and playout delay) were measured through pdu-SessionIdList, and based on the identification result, can optimize resource allocation and scheduling for the PDU session(s) indicated by this parameter.

[0126] The base station can read the RVQoE report and utilize it to perform network optimization. For example, the base station may determine that a specific terminal is experiencing poor QoE for a specific service based on the RVQoE report. In this case, the base station can improve the QoE of the terminal by allocating more radio resources to the terminal determined to be experiencing poor QoE. The terminal can (re)transmit the QoE measurement report that was not fully transmitted during the handover (e.g., after the handover is completed) to the new base station.

[0127] The terminal may perform, for example, all or part of the following sequence of operations.

[0128] 1) A terminal (e.g., UE AS and / or UE APP) can receive QoE configuration information (e.g., QoE configuration information or QoE measurement configuration) according to FIG. 1c or FIG. 1d.

[0129] 2) A terminal (e.g., UE AS and / or UE APP) can perform QoE measurement according to FIG. 1c or FIG. 1d.

[0130] 3) The UE AS can receive a QoE measurement report (e.g., QoE measurement report or QoE report) from the UE APP (e.g., 1c-55 or 1d-35).

[0131] 4) The UE AS can generate a QoE measurement report message (e.g., MeasurementReportAppLayer message) to transmit the QoE measurement report received from the UE APP.

[0132] 5) The terminal (e.g., UE AS and / or UE APP) can forward the QoE measurement report message to a lower layer to be transmitted to the base station (e.g., NG-RAN). The terminal can determine whether to perform RRC segmentation to forward the QoE measurement report message to the lower layer. The terminal can perform RRC segmentation if all of the following conditions are satisfied.

[0133] - Condition 1. When the size of the generated QoE measurement report message is larger than the size of the maximum SDU (Service Data Unit) supported by the lower layer (e.g., PDCP layer).

[0134] - Condition 2. If the terminal supports RRC segmentation

[0135] - Condition 3. If the base station allows RRC segmentation in the SRB (e.g., SRB4 or SRB5) used for QoE measurement reporting (e.g., sets at least one of the indicators rrc-SegAllowed, rrc-SegAllowedSRB4, or rrc-SegAllowedSRB5).

[0136] If all of the above conditions are satisfied, the terminal can perform RRC segmentation on the QoE report message to divide the QoE report message into multiple RRC segments. The multiple RRC segments can be transmitted from the terminal to the lower layer.

[0137] If at least one of the above conditions is not satisfied, the terminal may forward the QoE report message to a lower layer (e.g., PDCP layer) without segmenting it.

[0138] 6) The UE can receive an RRCReconfiguration message from the base station. The MCG (Master Cell Group)-related configuration information (e.g., masterCellGroup) in the RRCReconfiguration message can include a reconfigurationWithSync indicator. The reconfigurationWithSync indicator can mean that the base station instructs the UE to perform a handover to another base station (or cell) or an MN change (e.g., an MCG change).

[0139] 7) The terminal can apply the settings to the new base station included in the RRCReconfiguration message. The terminal can send the RRCReconfigurationComplete message to the new base station (or cell). The RRCReconfigurationComplete message can indicate the successful completion of the handover.

[0140] 8) The terminal can determine whether the QoE measurement report message or RRC segments have been successfully transmitted. For example, the terminal can receive confirmation from a lower layer whether the QoE measurement report message or RRC segments have been successfully transmitted.

[0141] If the terminal does not receive confirmation from the lower layer regarding successful transmission completion, it may determine that the transmission of the QoE measurement report to the previous base station (e.g., the source base station, the base station prior to the handover, or the cell) is not complete. Therefore, the terminal may retransmit the QoE measurement report message or RRC segments to the new base station to prevent loss or omission of the QoE measurement report.

[0142] If a terminal transmits at least one RRC segment (e.g., segment 1) to a previous base station and receives an acknowledgment for it from a lower layer, but does not receive an acknowledgment for the remaining RRC segments (e.g., segment 2) except for some of the transmitted RRC segments from the lower layer, the terminal may retransmit all RRC segments (e.g., segments 1 and segments 2) to a new base station. This is because the new base station may not have at least one of the RRC segments (e.g., segment 1) transmitted to the previous base station. In this case, the terminal needs to transmit all RRC segments (e.g., segments 1 and segments 2) to the base station, because the base station may not be able to assemble the existing QoE measurement report with only some of the RRC segments (e.g., segment 2).

[0143] The specific operation of the above terminal may be as shown in Table 9 below.

[0144] [Table 9]

[0145]

[0146] FIG. 1f is a diagram illustrating a procedure for retransmitting a QoE measurement report when a terminal performs a handover according to an embodiment of the present disclosure.

[0147] In the embodiment of FIG. 1F, the terminal may be defined as a UE AS or a UE APP, and the base station may be defined as an NG-RAN. The UE AS may be defined as the AS layer of the terminal, and the UE APP may be defined as the terminal application layer. The operations performed by the terminal may be interpreted as operations performed by the UE AS and / or the UE APP.

[0148] The specific actions performed by the terminal may be actions in the order mentioned above. The specific description of the actions performed in the following steps may follow the description in the order mentioned above. Therefore, some of the specific descriptions of the actions performed in the following steps may be omitted.

[0149] In step 1f-05, a terminal in a connected mode can perform a QoE measurement report (e.g., QoE reporting). In step 1f-10, the QoE measurement report of the terminal can be transmitted to the base station through SRB4 configured by the base station.

[0150] The UE AS can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The UE can transmit the QoE measurement report message to the base station.

[0151] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in step 1f-15. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0152] In step 1f-20, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via an RRCReconfiguration message as described above.

[0153] In step 1f-25, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) through SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the new base station through SRB4.

[0154] The UE AS can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The UE can transmit the QoE measurement report message to the base station.

[0155] If all conditions for performing the aforementioned RRC segmentation are satisfied, the terminal can perform RRC segmentation on the QoE measurement report message in step 1f-30 to generate RRC segments. The terminal can transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS can forward the RRC segments to a lower layer.

[0156] In step 1f-35, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via an RRCReconfgiuration message as described above.

[0157] In step 1f-40, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be retransmitted to the new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. The terminal may forward or transmit all RRC segments to the lower layer for retransmission of the RRC segments to the new base station via SRB4.

[0158] According to one embodiment of the present invention, a terminal can be configured with dual connectivity (DC) (e.g., NR-DC) from a base station. A terminal in DC state can be simultaneously connected to two base stations (a master node (MN) and a secondary node (SN)). If a terminal in DC state is configured with SRB4, the terminal can transmit a QoE measurement report to the MN via SRB4. If a terminal in DC state is configured with SRB5, the terminal can transmit a QoE measurement report to the SN via SRB5.

[0159] The terminal may be instructed to perform a handover or MN change as shown in FIG. 1f. As shown in FIG. 1f, if the terminal performs a handover and fails to successfully transmit the QoE measurement report transmitted to the previous base station via SRB4, the terminal in NR may retransmit the QoE measurement report to the new base station.

[0160] A terminal in NR can receive instructions for not only an MN change (or MCG change) but also an SN change (or SCG change). A terminal that receives such instructions can perform a handover to the instructed node (or cell).

[0161] For example, a terminal may receive an RRCReconfiguration message from a base station. The SCG (Secondary Cell Group)-related configuration information (e.g., secondaryCellGroup) in the RRCReconfiguration message may include a reconfigurationWithSync indicator. The reconfigurationWithSync indicator may indicate that the base station instructs the terminal to perform an SN change (or SCG change) to another base station (or cell).

[0162] When a terminal in NR receives an instruction for a SN change and performs a handover, it may not successfully transmit the QoE measurement report that was being transmitted to the previous SN via SRB5. In the following, the present disclosure defines an operation for the terminal to retransmit the QoE measurement report to the new SN to prevent loss or omission of the QoE measurement report.

[0163] If a QoE measurement report is not retransmitted to the SN, resulting in a loss or insufficient QoE measurement report, at least one of the TCE, MCE, or OAM that collects the QoE measurement report may perform incorrect network optimization actions. For example, if a loss of a QoE measurement report containing a measurement result indicating that the QoE of a terminal is poor occurs, at least one of the TCE, MCE, or OAM may make an incorrect judgment about the QoE of the terminal. If a wrong judgment is made that the QoE has never been poor during the QoE measurement session, actions to improve the poor QoE situation of the terminal may not be performed. If this situation is repeated, the terminal may continue to not receive improvement in the poor QoE.

[0164] FIG. 1g is a diagram illustrating a procedure for retransmitting a QoE measurement report when a terminal performs a handover (MN change) or SN change according to one embodiment of the present disclosure.

[0165] In the embodiment of FIG. 1g, the terminal may be defined as a UE AS or a UE APP, and the base station may be defined as an NG-RAN. The UE AS may be defined as the AS layer of the terminal, and the UE APP may be defined as the terminal application layer. The operations performed by the terminal may be interpreted as operations performed by the UE AS and / or the UE APP.

[0166] The specific actions performed by the terminal may be actions in the order mentioned above. The specific description of the actions performed in the following steps may follow the description in the order mentioned above. Therefore, some of the specific descriptions of the actions performed in the following steps may be omitted.

[0167] In step 1g-05, a terminal in a connected mode can perform QoE measurement reporting (e.g., QoE reporting).

[0168] In step 1g-10, the terminal's QoE measurement report can be transmitted to the base station through SRB4 set by the base station.

[0169] In the following steps, the operation of the terminal transmitting the QoE measurement report to the base station via SRB4 may follow the operation in FIG. 1f.

[0170] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0171] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in step 1g-15. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0172] In step 1g-20, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via an RRCReconfiguration message as described above.

[0173] In step 1g-25, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) through SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the new base station through SRB4.

[0174] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0175] If all conditions for performing the aforementioned RRC segmentation are satisfied, the UE may perform RRC segmentation on the QoE measurement report message in step 1g-30 to generate RRC segments. The UE may transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS may forward the RRC segments to a lower layer.

[0176] In step 1g-35, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via an RRCReconfgiuration message as described above.

[0177] In step 1g-40, if the UE does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), it may retransmit all RRC segments to the new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. The UE may forward or transmit all RRC segments to the lower layer to retransmit the RRC segments to the new base station via SRB4.

[0178] In step 1g-45, the terminal's QoE measurement report can be transmitted to the base station through SRB5 set by the base station.

[0179] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0180] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in step 1g-50. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0181] In step 1g-55, the terminal may be instructed by the base station to perform an SN change. The SN change instruction may be provided via an RRCReconfiguration message as described above.

[0182] In step 1g-60, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message to the previous base station (e.g., the source base station, the base station before the handover, or the cell) from the lower layer (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station after the handover, or the cell) through SRB5. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the new base station through SRB5.

[0183] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0184] If all conditions for performing the aforementioned RRC segmentation are satisfied, the UE may perform RRC segmentation on the QoE measurement report message in step 1g-65 to generate RRC segments. The UE may transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS may forward the RRC segments to a lower layer.

[0185] In step 1g-70, the terminal may be instructed by the base station to perform a SN change. The SN change instruction may be provided via an RRCReconfgiuration message as described above.

[0186] In step 1g-75, if the UE does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), it may retransmit all RRC segments to the new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. The UE may forward or transmit all RRC segments to the lower layer to retransmit the RRC segments to the new base station via SRB5.

[0187] When a terminal receives a QoE configuration, the terminal may be instructed by the base station (e.g., via an RRCReconfiguration message or an RRCResume message) which SRB (e.g., a reporting SRB or a reporting leg (e.g., reportingSRB)) the terminal should use for QoE measurement reporting. The reportingSRB may indicate at least one of SRB4 or SRB5. The terminal may be configured for multiple QoE measurements, and each QoE measurement may be distinguished by an RRC ID (e.g., measConfigAppLayerId). A reportingSRB may be separately instructed for each QoE measurement configuration. For example, if all reportingSRBs for all QoE measurements configured by the terminal are SRB4, the terminal may perform QoE measurement reporting only with SRB4. Alternatively, if all reportingSRBs for all QoE measurements configured by the terminal are SRB5, the terminal may perform QoE measurement reporting only with SRB5. Alternatively, if the reportingSRB for some QoE measurements set by the terminal is SRB4 and the reportingSRB for other QoE measurements is SRB5, the terminal can separately perform QoE measurement reporting to SRB4 and QoE measurement reporting to SRB5.

[0188] When a UE receives an RRCReconfiguration message from the base station indicating a handover or SN change, it may be instructed to send a reportingSRB. When performing a handover, the UE may not receive confirmation of successful transmission of the QoE report. In this case, the UE in NR can only retransmit the QoE measurement report using SRB4 (see Table 9).

[0189] When performing a handover or SN change, a UE may be instructed to use SRB5 as the reporting SRB. A UE that receives SRB5 as the reporting SRB can then transmit a QoE measurement report to SRB4. However, the base station (MN) may not understand the QoE measurement report or may not have the corresponding QoE settings. Therefore, it may not be able to forward the QoE measurement report to the TCE or MCE, which may result in loss or omission of the QoE measurement report.

[0190] FIG. 1h is a diagram illustrating a procedure for retransmitting a QoE measurement report according to a set SRB when a terminal performs a handover according to an embodiment of the present disclosure.

[0191] In the embodiment of FIG. 1h, the terminal may be defined as a UE AS or a UE APP, and the base station may be defined as an NG-RAN. The UE AS may be defined as the AS layer of the terminal, and the UE APP may be defined as the terminal application layer. The operations performed by the terminal may be interpreted as operations performed by the UE AS and / or the UE APP.

[0192] The specific actions performed by the terminal may be actions in the order mentioned above. The specific description of the actions performed in the following steps may follow the description in the order mentioned above. Therefore, some of the specific descriptions of the actions performed in the following steps may be omitted.

[0193] At step 1h-05, a terminal in a connected mode can perform QoE measurement reporting (e.g., QoE reporting).

[0194] In step 1h-10, the terminal's QoE measurement report can be transmitted to the base station through SRB4 set by the base station.

[0195] In the following steps, the operation of the terminal transmitting a QoE measurement report to the base station via SRB4 may follow the operation in FIG. 1f or FIG. 1g. In addition, in the following steps, the operation of the terminal transmitting a QoE measurement report to the base station via SRB5 may follow the operation in FIG. 1g.

[0196] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0197] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in steps 1h-15. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0198] In step 1h-20, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to the SRB4 from the base station via the QoE configuration in the RRCReconfiguration message indicating the handover.

[0199] In step 1h-25, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the QoE measurement report message may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID for which the reporting leg has been instructed to SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the new base station.

[0200] In step 1h-30, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to the SRB5 from the base station via the QoE configuration in the RRCReconfiguration message indicating the handover.

[0201] In step 1h-35, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the QoE measurement report message may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID for which the reporting leg has been instructed to SRB5. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the new base station.

[0202] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0203] If all conditions for performing the aforementioned RRC segmentation are satisfied, the terminal can perform RRC segmentation on the QoE measurement report message in step 1h-40 to generate RRC segments. The terminal can transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS can forward the RRC segments to a lower layer.

[0204] In step 1h-45, the terminal may be instructed to perform a handover by the base station. The handover instruction may be provided through the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to SRB4 by the base station through the QoE configuration in the RRCReconfiguration message indicating the handover.

[0205] In step 1h-50, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. At this time, the retransmission of RRC segments may be performed only for the QoE configuration ID for which the reporting leg has been instructed to SRB4. The terminal may forward or transmit all RRC segments to the lower layer in order to retransmit the RRC segments to the new base station.

[0206] In step 1h-55, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to the SRB5 from the base station via the QoE configuration in the RRCReconfiguration message indicating the handover.

[0207] In step 1h-60, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. At this time, the retransmission of RRC segments may be performed only for the QoE configuration ID that has been instructed to the SRB5 through the reporting leg. The terminal may forward or transmit all RRC segments to the lower layer in order to retransmit the RRC segments to the new base station.

[0208] The terminal can forward the QoE measurement report message to the lower layer to transmit it to the base station. The terminal can determine whether to perform RRC segmentation to forward the QoE measurement report message to the lower layer. The terminal can perform RRC segmentation if all of the above conditions are satisfied. As one of the above conditions, if the base station allows or supports performing RRC segmentation in the SRB used for QoE measurement report (for example, if at least one indicator among rrc-SegAllowed, rrc-SegAllowedSRB4, or rrc-SegAllowedSRB5 is set), the terminal can perform RRC segmentation.

[0209] In NR, a UE can retransmit QoE measurement report segments to a new eNB during a handover, regardless of whether the new eNB allows RRC segmentation (see Table 9). However, if the new eNB does not allow or support RRC segmentation and the UE transmits RRC segments, the eNB may not be able to understand or assemble the RRC segments. If the eNB cannot understand or assemble the RRC segments, it may ignore or discard the received QoE measurement report, which may result in loss or omission of the QoE measurement report. This may result in incorrect network optimization in at least one of the TCE, MCE, or OAM that collects the QoE measurement report. Furthermore, radio resources and energy of the UE may be consumed in transmitting the RRC segments, resulting in waste of resources and energy of the UE.

[0210] FIG. 1i is a diagram illustrating a procedure for retransmitting a QoE measurement report depending on whether a new base station allows RRC segmentation when a terminal performs a handover according to one embodiment of the present disclosure.

[0211] In the embodiment of FIG. 1i, the terminal may be defined as a UE AS or a UE APP, and the base station may be defined as an NG-RAN. The UE AS may be defined as the AS layer of the terminal, and the UE APP may be defined as the terminal application layer. The operations performed by the terminal may be interpreted as operations performed by the UE AS and / or the UE APP.

[0212] The specific actions performed by the terminal may be actions in the order mentioned above. The specific description of the actions performed in the following steps may follow the description in the order mentioned above. Therefore, some of the specific descriptions of the actions performed in the following steps may be omitted.

[0213] In step 1i-05, a terminal in connected mode can perform QoE measurement reporting (e.g., QoE reporting).

[0214] In step 1i-10, the terminal's QoE measurement report can be transmitted to the base station through SRB4 set by the base station.

[0215] In the following steps, the operation of the terminal transmitting the QoE measurement report to the base station via SRB4 may follow the operation in FIG. 1f, FIG. 1g, or FIG. 1h.

[0216] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0217] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in steps 1i-15. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0218] In steps 1i-20, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via an RRCReconfiguration message as described above.

[0219] In step 1i-25, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) through SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer to retransmit the QoE measurement report message to the new base station.

[0220] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0221] If all conditions for performing the aforementioned RRC segmentation are satisfied, the terminal can perform RRC segmentation on the QoE measurement report message in step 1i-30 to generate RRC segments. The terminal can transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS can forward the RRC segments to a lower layer.

[0222] In step 1i-35, the terminal may be instructed to perform a handover from the base station. The handover instruction may be provided via the RRCReconfiguration message as described above. The RRCReconfiguration message indicating the handover may include QoE settings. At this time, the base station may indicate through RRCReconfiguration that the new base station allows RRC segmentation for QoE measurement reports using SRB4.

[0223] In step 1i-40, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), it may retransmit all RRC segments to the new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. The terminal may forward or transmit all RRC segments to the lower layer to retransmit the RRC segments to the new base station.

[0224] In step 1i-45, the terminal may be instructed to perform a handover by the base station. The RRCReconfiguration message indicating the handover may include QoE settings. At this time, the base station may indicate through RRCReconfiguration that the new base station does not allow RRC segmentation for QoE measurement reports using SRB4.

[0225] In step 1i-50, if the terminal does not receive confirmation of successful transmission of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station before the handover, or the cell) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be discarded without retransmitting. The discarding of RRC segments may be due to the new base station not allowing RRC segmentation.

[0226] FIG. 1ja and FIG. 1jb are diagrams illustrating a procedure for retransmitting a QoE measurement report depending on whether the configured SRB and the RRC segmentation of the new base station are permitted when a terminal performs a handover (MN change) or SN change according to one embodiment of the present disclosure.

[0227] In the embodiments of FIGS. 1ja and 1jb, the terminal may be defined as a UE AS or a UE APP, and the base station may be defined as an NG-RAN. The UE AS may be defined as the AS layer of the terminal, and the UE APP may be defined as the terminal application layer. The operations performed by the terminal may be interpreted as operations performed by the UE AS and / or the UE APP.

[0228] The specific actions performed by the terminal may be actions in the order mentioned above. The specific description of the actions performed in the following steps may follow the description in the order mentioned above. Therefore, some of the specific descriptions of the actions performed in the following steps may be omitted.

[0229] In step 1j-05, a terminal in a connected mode can perform QoE measurement reporting (e.g., QoE reporting).

[0230] In step 1j-10, the terminal's QoE measurement report can be transmitted to the base station through SRB4 set by the base station.

[0231] In the following steps, the operation of the terminal transmitting the QoE measurement report to the base station via SRB4 may follow the operation in FIG. 1f, FIG. 1g, FIG. 1h, or FIG. 1i.

[0232] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0233] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in steps 1j-15. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0234] In steps 1j-20, the terminal may be instructed to perform a handover by the base station. The handover instruction may be provided via the RRCReconfiguration message as described above. The terminal may be instructed to report to the SRB4 the reporting leg for some or all of the QoE configuration IDs from the base station via the QoE configuration in the RRCReconfiguration message indicating the handover.

[0235] In step 1j-25, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) through SRB4. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID for which the reporting leg has been instructed to SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer before retransmitting the QoE measurement report message to the base station.

[0236] In step 1j-30, the terminal may be instructed to perform a handover from the base station. The handover instruction may be indicated via the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to the SRB5 from the base station via the QoE configuration in the RRCReconfiguration message indicating the handover.

[0237] In step 1j-35, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID that has been instructed to the reporting leg by SRB5. The terminal may forward or transmit the QoE measurement report message to the lower layer before retransmitting the QoE measurement report message to the new base station.

[0238] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0239] If all conditions for performing the aforementioned RRC segmentation are satisfied, the terminal can perform RRC segmentation on the QoE measurement report message in step 1j-40 to generate RRC segments. The terminal can transmit the RRC segments to the base station. To transmit the RRC segments to the base station, the UE AS can forward the RRC segments to a lower layer.

[0240] In step 1j-45, the terminal may be instructed to perform a handover from the base station. The handover instruction may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed by the base station to report some or all of the QoE configuration IDs to SRB4 through the QoE configuration in the RRCReconfiguration message instructing the handover. In addition, the RRCReconfiguration message instructing the handover may include a QoE configuration. The QoE configuration may indicate that the new base station allows RRC segmentation for QoE measurement reporting using SRB4.

[0241] In step 1j-50, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. At this time, the retransmission of RRC segments may be performed only for the QoE configuration ID that has been instructed to the reporting leg to SRB4. The terminal may forward or transmit all RRC segments to the lower layer in order to retransmit the RRC segments to the new base station.

[0242] In step 1j-55, the terminal may be instructed to perform a handover from the base station. The handover instruction may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to SRB5 from the base station through the QoE configuration in the RRCReconfiguration message instructing the handover. In addition, the RRCReconfiguration message instructing the handover may include a QoE configuration. The QoE configuration may indicate that the new base station allows RRC segmentation for QoE measurement reporting using SRB5.

[0243] In step 1j-60, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), it may retransmit all RRC segments to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. At this time, the retransmission of RRC segments may be performed only for the QoE configuration ID that has been instructed to the reporting leg to SRB5. The terminal may forward or transmit all segments to the lower layer before retransmitting the RRC segments to the new base station.

[0244] In step 1j-65, the terminal may be instructed to perform a handover from the base station. The handover instruction may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed to report some or all of the QoE configuration IDs to the SRB4 from the base station through the QoE configuration in the RRCReconfiguration message instructing the handover. In addition, the RRCReconfiguration message instructing the handover may include a QoE configuration. The QoE configuration may indicate that the new base station does not allow RRC segmentation for QoE measurement reporting using SRB4.

[0245] In step 1j-70, if the terminal does not receive confirmation of successful transmission of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell prior to the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be discarded without retransmitting. This may be because the new base station does not allow or support RRC segmentation.

[0246] In step 1j-75, the terminal may be instructed to perform a handover from the base station. The handover instruction may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed by the base station to report some or all of the QoE configuration IDs to SRB5 through the QoE configuration in the RRCReconfiguration message instructing the handover. In addition, the RRCReconfiguration message instructing the handover may include a QoE configuration. The QoE configuration may indicate that the new base station does not allow RRC segmentation for QoE measurement reporting using SRB5.

[0247] In step 1j-80, if the terminal does not receive confirmation of successful transmission of at least one RRC segment from a lower layer to the previous base station (e.g., the source base station, the base station or cell prior to the handover) (or if the transmission of at least one RRC segment is not completed), it may discard all RRC segments without retransmitting them. This may be because the new base station does not allow or support RRC segmentation.

[0248] In step 1j-85, the terminal's QoE measurement report can be transmitted to the base station through SRB5 set by the base station.

[0249] In the following steps, the operation of the terminal transmitting the QoE measurement report to the base station via SRB5 may follow the operation in FIG. 1g or FIG. 1h.

[0250] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0251] If at least one of the conditions for performing the above-mentioned RRC segmentation is not satisfied, RRC segmentation may not be performed. The UE AS may transmit a QoE measurement report message to the base station (without performing RRC segmentation) in step 1j-90. To transmit the QoE measurement report message to the base station, the UE AS may forward the QoE measurement report message to a lower layer.

[0252] In step 1j-95, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed by the base station to report to SRB5 some or all of the QoE configuration IDs through the QoE configuration in the RRCReconfiguration message indicating the SN change.

[0253] In step 1j-100, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the terminal may retransmit the QoE measurement report message to a new base station (e.g., the target base station, the base station or cell after the handover) through SRB5. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID for which the reporting leg has been instructed to SRB5. The terminal may forward or transmit the QoE measurement report message to the lower layer in order to retransmit the QoE measurement report message to the base station.

[0254] In step 1j-105, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through the RRCReconfiguration message as described above. The terminal may be instructed by the base station to report to SRB4 some or all of the QoE configuration IDs through the QoE configuration in the RRCReconfiguration message indicating the SN change.

[0255] In step 1j-110, if the terminal does not receive confirmation of successful transmission completion of the QoE measurement report message from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of the QoE measurement report message is not completed), the QoE measurement report message may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. At this time, the retransmission of the QoE measurement report message may be performed only for the QoE configuration ID that has been instructed to the reporting leg by SRB4. The terminal may forward or transmit the QoE measurement report message to the lower layer before retransmitting the QoE measurement report message to the new base station.

[0256] A terminal can generate (encode) a QoE measurement report message using QoE measurement report information received from an upper layer. The terminal can transmit the QoE measurement report message to a base station.

[0257] If all conditions for performing the aforementioned RRC segmentation are satisfied, the terminal can perform RRC segmentation on the QoE measurement report message in 1j-115 to generate RRC segments. The terminal can transmit the RRC segments to the base station. The UE AS that transmits the RRC segments to the base station can forward the RRC segments to a lower layer.

[0258] In step 1j-120, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through an RRCReconfiguration message as described above. The terminal may be instructed by the base station to report a part or all of the QoE configuration ID to SRB5 through a QoE configuration in the RRCReconfiguration message indicating the SN change. In addition, the RRCReconfiguration message indicating the SN change may include a QoE configuration. The QoE configuration may indicate that the new base station allows RRC segmentation for QoE measurement reporting using SRB5.

[0259] In step 1j-125, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if transmission of at least one segment is not completed), all RRC segments may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB5. At this time, retransmission of RRC segments may be performed only for QoE configuration IDs that have been instructed to the SRB5 through the reporting leg. The terminal may forward or transmit all RRC segments to the lower layer in order to retransmit the RRC segments to the new base station.

[0260] In step 1j-130, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through an RRCReconfiguration message as described above. The terminal may be instructed by the base station to report a part or all of the QoE configuration ID to SRB4 through a QoE configuration in the RRCReconfiguration message indicating the SN change. In addition, the RRCReconfiguration message indicating the SN change may include a QoE configuration. The QoE configuration may indicate that the new base station allows RRC segmentation for QoE measurement reporting using SRB4.

[0261] In step 1j-135, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell before the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be retransmitted to a new base station (e.g., the target base station, the base station or cell after the handover) via SRB4. At this time, the retransmission of RRC segments may be performed only for the QoE configuration ID that has been instructed to the reporting leg to SRB4. The terminal may forward or transmit all RRC segments to the lower layer in order to retransmit the RRC segments to the new base station.

[0262] In step 1j-140, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through an RRCReconfiguration message as described above. The terminal may be instructed by the base station to report a part or all of the QoE configuration ID to SRB5 through a QoE configuration in the RRCReconfiguration message indicating the SN change. In addition, the RRCReconfiguration message indicating the SN change may include a QoE configuration. The QoE configuration may indicate that the new base station does not allow RRC segmentation for QoE measurement reporting using SRB5.

[0263] In step 1j-145, if the terminal does not receive confirmation of successful transmission of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station or cell prior to the handover) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be discarded without retransmitting. This may be because the new base station does not allow or support RRC segmentation.

[0264] In step 1j-150, the terminal may be instructed by the base station to perform a SN change. The SN change may be instructed through an RRCReconfiguration message as described above. The terminal may be instructed by the base station to report a part or all of the QoE configuration ID to SRB4 through a QoE configuration in the RRCReconfiguration message indicating the SN change. In addition, the RRCReconfiguration message indicating the SN change may include a QoE configuration. The QoE configuration may indicate that the new base station does not allow RRC segmentation for QoE measurement reporting using SRB4.

[0265] In step 1j-155, if the terminal does not receive confirmation of successful transmission completion of at least one RRC segment from the lower layer to the previous base station (e.g., the source base station, the base station before the handover, or the cell) (or if the transmission of at least one RRC segment is not completed), all RRC segments may be discarded without retransmitting. This may be because the new base station does not allow or support RRC segmentation.

[0266] The QoE measurement report message or RRC segments retransmitted by the UE may include QoE measurement reports for multiple QoE measurement configuration IDs (e.g., measConfigAppLayerId). When the UE is instructed to perform a handover or SN change, the UE may set the reporting SRB for some of the QoE measurement configuration IDs (e.g., SRB4) to different values ​​and the reporting SRB for the remaining IDs (e.g., SRB5).

[0267] According to Table 9, a terminal in NR can transmit the QoE measurement report message or RRC segments that it was previously intended to send through SRB4. At this time, if a QoE measurement report for a QoE configuration ID instructed to be transmitted to SRB5 is transmitted to the MN, the MN may not understand it or may not have the relevant configuration, and may discard the received QoE measurement report. This may cause a problem that results in the loss or omission of the QoE measurement report.

[0268] The UE can be instructed to perform a handover or SN change from the base station. The handover or SN change can be instructed through an RRCReconfiguration message. Through the QoE configuration in the RRCReconfiguration message, the base station can instruct the same reporting SRB for all QoE configuration IDs. The UE can retransmit the QoE measurement report message or RRC segments that were not successfully transmitted to the previous base station to the new base station. In this case, the UE can transmit the QoE measurement report message or RRC segments as is.

[0269] However, the base station may indicate a different reporting SRB for at least one QoE configuration ID in the RRCReconfiguration message. In this case, the terminal may discard the QoE measurement report message or RRC segments that were not successfully transmitted to the previous base station when retransmitting them to the new base station.

[0270] The terminal can generate or encode a message including only a QoE measurement report for a QoE configuration ID indicated by SRB4 and a message including only a QoE measurement report for a QoE configuration ID indicated by SRB5. The message including only a QoE measurement report for a QoE configuration ID indicated by SRB4 can be transmitted to SRB4. Additionally, the message including only a QoE measurement report for a QoE configuration ID indicated by SRB5 can be transmitted to SRB5. If the QoE report message satisfies all of the predetermined conditions described above, the QoE report message can be transmitted after RRC segmentation is performed.

[0271] As an example of the present disclosure, the terminal can perform operations according to Table 10 below.

[0272] [Table 10]

[0273]

[0274]

[0275] As an example of the present disclosure, the terminal can perform operations according to Table 11 below.

[0276] [Table 11]

[0277]

[0278]

[0279]

[0280] FIG. 1k is a drawing illustrating the internal structure of a terminal according to an example of the present disclosure.

[0281] Referring to FIG. 1k, the terminal includes an RF (Radio Frequency) processing unit (1k-10), a baseband processing unit (1k-20), a storage unit (1k-30), and a control unit (1k-40).

[0282] The RF processing unit (1k-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1k-10) up-converts the baseband signal provided from the baseband processing unit (1k-20) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1k-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In the drawing, only one antenna is illustrated, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit (1k-10) may include multiple RF chains. Furthermore, the RF processing unit (1k-10) may perform beamforming. For the above beamforming, the RF processing unit (1k-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit can perform MIMO and receive multiple layers when performing the MIMO operation.

[0283] The baseband processing unit (1k-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (1k-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1k-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (1k-10). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (1k-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing an inverse fast Fourier transform (IFFT) operation and inserting a cyclic prefix (CP). In addition, when receiving data, the baseband processing unit (1k-20) divides the baseband signal provided from the RF processing unit (1k-10) into OFDM symbol units, restores signals mapped to subcarriers through FFT (fast Fourier transform) operation, and then restores the received bit string through demodulation and decoding.

[0284] The baseband processing unit (1k-20) and the RF processing unit (1k-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1k-20) and the RF processing unit (1k-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (1k-20) and the RF processing unit (1k-10) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (1k-20) and the RF processing unit (1k-10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band and a millimeter wave (mm wave) (e.g., 60GHz) band.

[0285] The storage unit (1k-30) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (1k-30) can store information related to a second access node that performs wireless communication using wireless access technology. In addition, the storage unit (1k-30) provides the stored data at the request of the control unit (1k-40).

[0286] The control unit (1k-40) controls the overall operations of the terminal. For example, the control unit (1k-40) transmits and receives signals through the baseband processing unit (1k-20) and the RF processing unit (1k-10). In addition, the control unit (1k-40) records and reads data in the storage unit (1k-30). For this purpose, the control unit (1k-40) may include at least one processor. For example, the control unit (1k-40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs, and may include a multi-connection processing unit (1k-42) as illustrated in the drawing. The control unit (1k-40) may control the operations of the terminal according to various embodiments of the present disclosure. Additionally, the control unit (1k-40) can control the operation of the UE AS and the UE APP according to various embodiments of the present disclosure.

[0287] FIG. 1l is a diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0288] Referring to FIG. 1l, a base station according to an example of the present disclosure is configured to include an RF processing unit (1l-10), a baseband processing unit (1l-20), a backhaul communication unit (1l-30), a storage unit (1l-40), and a control unit (1l-50).

[0289] The RF processing unit (11-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (11-10) up-converts the baseband signal provided from the baseband processing unit (11-20) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (11-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In the drawing, only one antenna is shown, but the base station may have multiple antennas. In addition, the RF processing unit (11-10) may include multiple RF chains. Furthermore, the RF processing unit (11-10) may perform beamforming. For the above beamforming, the RF processing unit (11-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform a downlink MIMO operation by transmitting one or more layers.

[0290] The baseband processing unit (11-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the wireless access technology. For example, when transmitting data, the baseband processing unit (11-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (11-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (11-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (11-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (11-20) divides the baseband signal provided from the RF processing unit (11-10) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operation, and then restores the received bit string through demodulation and decoding. The baseband processing unit (11-20) and the RF processing unit (11-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (11-20) and the RF processing unit (11-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0291] The above backhaul communication unit (1l-30) provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (1l-30) converts a bit string transmitted from the main base station to another node, such as an auxiliary base station or core network, into a physical signal, and converts a physical signal received from the other node into a bit string.

[0292] The storage unit (11-40) stores data such as basic programs, application programs, and setting information for the operation of the main base station. In particular, the storage unit (11-40) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (11-40) can store information that serves as a judgment criterion for whether to provide or terminate multiple connections to a terminal. In addition, the storage unit (11-40) provides the stored data at the request of the control unit (11-50).

[0293] The control unit (11-50) controls the overall operations of the base station. For example, the control unit (11-50) transmits and receives signals through the baseband processing unit (11-20) and the RF processing unit (11-10) or through the backhaul communication unit (11-30). In addition, the control unit (11-50) records and reads data in the storage unit (11-40). For this purpose, the control unit (11-50) may include at least one processor and may include a multi-connection processing unit (11-52) as illustrated in the drawing. The control unit (11-50) may control the operation of the base station and / or the operation of the NG-RAN according to various embodiments of the present disclosure.

[0294] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0295] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0296] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0297] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0298] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0299] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the above-described embodiments can be combined and operated as needed. For example, parts of one embodiment of the present disclosure and another embodiment can be combined to operate a base station and a terminal. Furthermore, the embodiments of the present disclosure can be applied to other communication systems, and other modifications based on the technical idea of ​​the embodiments can also be implemented. For example, the embodiments can be applied to LTE systems, 5G, NR systems, or 6G systems. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be determined not only by the scope of the following claims but also by equivalents of the claims.

Claims

1. In a method performed by a terminal in a communication system, A step of receiving a radio resource control (RRC) message, wherein the RRC message includes at least one QoE measurement configuration including information about a signaling radio bearer (SRB) to report a result of a quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group; A step of identifying whether the transmission of the QoE measurement report message is successful based on reception of the RRC message, wherein the transmission of the QoE measurement report message is based on the established SRB; If the success or failure of the transmission of the QoE measurement report message is not confirmed, a step of identifying whether RRC segmentation for the QoE measurement report message has been used; and A method characterized by comprising: a step of transmitting all segments of the QoE measurement report message based on an SRB to which the result of the QoE measurement is to be reported, when RRC segmentation for the QoE measurement report message is used and when the RRC segmentation for the QoE measurement report message is allowed in the changed cell group; 2. In paragraph 1, A method characterized in that it further includes a step of discarding all segments for the QoE measurement report message if the RRC segmentation is not allowed in the changed cell group.

3. In paragraph 1, A method characterized in that it further comprises a step of transmitting the QoE measurement report message based on an SRB to report the result of the QoE measurement, when RRC segmentation for the QoE measurement report message is not used.

4. In paragraph 1, The above cell group includes either a master cell group (MCG) or a secondary cell group (SCG), The above set SRB indicates either SRB4 or SRB5, and A method characterized in that the SRB to report the result of the above QoE measurement indicates either SRB4 or SRB5.

5. In a method performed by a base station in a communication system, A step of transmitting a radio resource control (RRC) message to a terminal, the RRC message including at least one QoE measurement configuration including information about a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group; and A step of receiving a message regarding completion of a cell group change from the terminal; A method characterized in that, if the transmission of the QoE measurement report message by the terminal is not successfully performed based on an SRB set, RRC segmentation for the QoE measurement report message is used, and the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, all segments of the QoE measurement report message are transmitted to the changed cell group based on an SRB to which the result of the QoE measurement is to be reported.

6. In paragraph 5, A method characterized in that if the RRC segmentation is not allowed in the changed cell group, all segments for the QoE measurement report message are discarded.

7. In paragraph 5, A method characterized in that, when RRC segmentation for the QoE measurement report message is not used, the QoE measurement report message is transmitted based on an SRB to report the result of the QoE measurement.

8. In paragraph 5, The above cell group includes either a master cell group (MCG) or a secondary cell group (SCG), The above set SRB indicates either SRB4 or SRB5, and A method characterized in that the SRB to report the result of the above QoE measurement indicates either SRB4 or SRB5.

9. In the terminal of the communication system, the terminal Transmitter and receiver; and A control unit connected to the above transmitter and receiver, wherein the control unit: Receiving a radio resource control (RRC) message, wherein the RRC message includes at least one QoE measurement configuration including information about a signaling radio bearer (SRB) to report a result of a quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group, Based on the reception of the RRC message, it is identified whether the transmission of the QoE measurement report message is successful, and the transmission of the QoE measurement report message is based on the established SRB. If the success of the above transmission of the above QoE measurement report message is not confirmed, identify whether RRC segmentation for the above QoE measurement report message was used, and A terminal characterized in that, when RRC segmentation for the QoE measurement report message is used and when the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, all segments of the QoE measurement report message are transmitted based on the SRB to which the result of the QoE measurement is to be reported.

10. In paragraph 9, the control unit: A terminal characterized in that, if the RRC segmentation is not allowed in the changed cell group, all segments for the QoE measurement report message are discarded.

11. In paragraph 9, the control unit: A terminal characterized in that, when RRC segmentation for the QoE measurement report message is not used, the QoE measurement report message is transmitted based on an SRB for reporting the result of the QoE measurement.

12. In paragraph 9, The above cell group includes either a master cell group (MCG) or a secondary cell group (SCG), The above set SRB indicates either SRB4 or SRB5, and A terminal characterized in that the SRB to report the result of the above QoE measurement indicates either SRB4 or SRB5.

13. In a base station of a communication system, the base station is Transmitter and receiver; and A control unit connected to the above transmitter and receiver, wherein the control unit: Transmitting a radio resource control (RRC) message to a terminal, wherein the RRC message includes at least one QoE measurement configuration including information about a signaling radio bearer (SRB) to report a result of quality of experience (QoE) measurement and information indicating whether to allow RRC segmentation for a QoE measurement report message including a result of the QoE measurement in a changed cell group, and Receive a message from the above terminal regarding the completion of cell group change, A base station characterized in that, when the transmission of the QoE measurement report message by the terminal is not successfully performed based on an SRB set, RRC segmentation for the QoE measurement report message is used, and the RRC segmentation for the QoE measurement report message is allowed in the changed cell group, all segments of the QoE measurement report message are transmitted to the changed cell group based on an SRB to which the result of the QoE measurement is to be reported.

14. In paragraph 13, A base station characterized in that if the RRC segmentation is not allowed in the changed cell group, all segments for the QoE measurement report message are discarded.

15. In paragraph 13, If RRC segmentation for the above QoE measurement report message is not used, the above QoE measurement report message is transmitted based on the SRB that reports the result of the above QoE measurement, The above cell group includes either a master cell group (MCG) or a secondary cell group (SCG), The above set SRB indicates either SRB4 or SRB5, and A base station characterized in that the SRB to report the result of the above QoE measurement indicates either SRB4 or SRB5.

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