Method and apparatus for managing RLF information by terminal supporting dual activation protocol stack in next generation mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The invention provides a method and equipment for distinguishing whether switching failure information occurs due to general switching failure or due to DAPS switching failure. Another purpose of the invention is to provide a method and equipment for managing conflicts if a plurality of gaps with the same priority exist.

Description

Technical Field

[0001] The present disclosure relates to a terminal and a base station in a wireless communication system. More particularly, the present disclosure relates to terminal and base station operations in a radio link failure (RLF) situation. Background Art

[0002] 5G mobile communication technology defines a wide frequency band, making high transmission rates and new services possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called mmWave including 28 GHz and 39 GHz. In addition, implementation of 6G mobile communication technology (called super 5G system) in terahertz frequency bands (e.g., 95 GHz to 3 THz frequency bands) has been considered to achieve a transmission rate 50 times faster than 5G mobile communication technology and an ultra-low latency of one-tenth of 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology development, in order to support services and meet performance requirements associated with enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), and massive machine type communications (mMTC), standardization has been underway on beamforming and massive MIMO for mitigating radio wave path loss and increasing radio wave transmission distance in mmWave, support for dynamic operation of parameter sets (e.g., operating multiple subcarrier spacings) and slot formats for efficient utilization of mmWave resources, initial access technology for supporting multi-beam transmission and broadband, definition and operation of bandwidth parts (BWPs), new channel coding and decoding methods (such as low-density parity-check (LDPC) codes for large amounts of data transmission and polar codes for highly reliable control information transmission), L2 preprocessing, and standardization of network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, discussions are underway on improvements and performance enhancements of initial 5G mobile communication technologies in consideration of the services that 5G mobile communication technologies will support, and there is already physical layer standardization on technologies such as Vehicle-to-Everything (V2X) for assisting driving determination of autonomous vehicles based on information about the location and status of vehicles transmitted by vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) designed for system operation to comply with various regulatory-related requirements in unlicensed frequency bands, NR UE power saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In addition, standardization is being conducted in air interface architecture / protocols on technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access (2-step RACH for NR) for simplifying the random access procedure. Standardization is also being conducted in system architecture / services on 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] As 5G mobile communication systems are commercialized, an exponentially growing number of connected devices will be connected to the communication network, and therefore, it is expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is planned in relation to efficient support for extended reality (XR) such as augmented reality (AR), virtual reality (VR), mixed reality (MR), etc., 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing coverage in the terahertz band for 6G mobile communication technology, multi-antenna transmission technologies (such as full-dimensional MIMO (FD-MIMO), array antennas, and large antennas), metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), but also full-duplex technologies for improving frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for implementing system optimization by utilizing satellites and artificial intelligence (AI) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services with a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources. Summary of the invention

[0008] Technical issues

[0009] The present disclosure aims to solve the above-mentioned problem and aims to provide a method for distinguishing whether a handover failure occurs due to a dual active protocol stack (DAPS) handover failure.

[0010] More specifically, an object of the present disclosure is to propose a method and apparatus for distinguishing whether handover failure information stored in a VarRLF-Report variable is due to a general handover failure or a DAPS handover failure when a DAPS handover failure occurs in a mobile communication system.

[0011] Another object of the present disclosure is to propose a method and apparatus for managing conflicts if there are multiple slots with the same priority.

[0012] Technical Solution

[0013] The present disclosure for solving the above-mentioned problem is characterized by providing a method performed by a terminal in a wireless communication system, the method including: receiving measurement configuration information from a base station, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; determining which one of the plurality of measurement gaps is to be applied; and performing a gap operation by applying a specifically determined measurement gap.

[0014] The present disclosure for solving the above-mentioned problem is characterized by providing a method performed by a base station in a wireless communication system, the method comprising: generating measurement configuration information to a terminal, the measurement configuration information comprising a plurality of measurement gaps having overlapping time axes and having the same priority; and sending the measurement configuration information including the plurality of measurement gaps to the terminal, wherein a gap operation is performed based on a specific measurement gap among the plurality of measurement gaps.

[0015] The present disclosure for solving the above-mentioned problem is characterized in that, in a terminal in a wireless communication system, a transceiver for sending and receiving a signal is included; and a control unit is included, wherein the control unit receives measurement configuration information from a base station, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; determines which one of the plurality of measurement gaps is to be applied; and performs a gap operation by applying a specifically determined measurement gap.

[0016] The present disclosure for solving the above-mentioned problem is characterized in that, in a base station in a wireless communication system, a transceiver for sending and receiving signals is included; and a control unit is included, wherein the control unit generates measurement configuration information to a terminal, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; and the measurement configuration information including the plurality of measurement gaps is sent to the terminal, wherein a gap operation is performed based on a specific measurement gap among the plurality of measurement gaps.

[0017] Advantageous Effects of the Invention

[0018] According to an embodiment of the present disclosure, it is possible to distinguish whether a handover failure is caused by a general handover failure or a DAPS handover failure. More specifically, in the case of a DAPS handover failure, by not storing handover failure information in a Var-RLF report (Var-RLF-Report) variable or storing information indicating this in a Var-RLF-Report variable, it is possible to distinguish whether the handover failure occurs as a general handover failure or as a DAPS handover failure.

[0019] In addition, according to another embodiment of the present disclosure, it is possible to determine which of multiple measurement gaps with the same priority is to be applied. More specifically, if there are multiple gaps with the same priority, the gap operation can be performed according to an instruction from the base station or by reflecting the preferred gap information of the terminal.

[0020] Advantageous effects obtainable from the present disclosure may not be limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present disclosure belongs through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 a is a diagram showing a structure of a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0022] FIG. 1 b is a diagram illustrating a radio protocol structure in a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0023] FIG. 1c is a diagram showing a structure of a next generation mobile communication system according to an embodiment of the present disclosure.

[0024] FIG. 1d is a diagram illustrating a wireless protocol structure of a next generation mobile communication system according to an embodiment of the present disclosure.

[0025] FIG. 1e is a flowchart of a process for performing a general handover operation in a mobile communication system according to an embodiment of the present disclosure.

[0026] FIGS. 1fa , 1fb , and 1fc are diagrams illustrating a process of using a dual active protocol stack (DAPS) in a process of performing a handover according to an embodiment of the present disclosure.

[0027] FIG. 1g is a flow chart of a process for performing a dual active protocol stack (DAPS) switch according to an embodiment of the present disclosure.

[0028] FIG1h is a flowchart of terminal operations after a dual active protocol stack (DAPS) switching failure according to an embodiment of the present disclosure.

[0029] FIG. 1i is a flowchart of terminal operations after a dual active protocol stack (DAPS) switching failure according to an embodiment of the present disclosure.

[0030] FIG. 1j is a flowchart of operations of a terminal and a base station managing conflict if there are multiple gaps having the same priority according to an embodiment of the present disclosure.

[0031] FIG. 1k is a flowchart of an operation of a terminal and a base station managing a conflict if there are a plurality of gaps having the same priority according to another embodiment of the present disclosure.

[0032] FIG. 11 is a block diagram showing an internal structure of a terminal according to an embodiment of the present disclosure.

[0033] FIG. 1m is a block diagram showing the structure of a base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] When describing the embodiments in this specification, descriptions of technical contents that are well known in the technical field to which the present invention belongs and are not directly related to the present invention will be omitted. This is to convey the gist of the present invention more clearly without obscuring the present invention by omitting unnecessary explanations.

[0035] For the same reason, some components in the accompanying drawings are enlarged, omitted or schematically shown. In addition, the size of each component does not fully reflect its actual size. In each of the accompanying drawings, the same or corresponding components are given the same reference numerals.

[0036] The advantages and features of the present invention and methods of achieving them will become clear by referring to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and the embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform the scope of the present invention to those of ordinary skill in the art to which the present invention belongs, and the present invention is limited only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0037] At this point, it will be understood that each block of the process flow chart diagram and the combination of the flow chart diagrams can be performed by computer program instructions. These computer program instructions can be installed on a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that these instructions, when executed by the processor of the computer or other programmable data processing device, create components for performing the functions described in the flow chart blocks. These computer program instructions can be stored in a computer-usable or computer-readable memory, which can be directed to a computer or other programmable data processing device to implement the functions in a specific manner, so that the instructions stored in the computer-usable or computer-readable memory can produce an article of manufacture including instruction components for performing the functions described in the flow chart blocks. The computer program instructions can also be installed on a computer or other programmable data processing device, and a series of operating steps are performed on the computer or other programmable data processing device to create a computer executable process, so that the instructions of the executing computer or other programmable data processing device can also provide steps for performing the functions described in the flow chart blocks.

[0038] In addition, each block can represent a module, segment or part of a code including one or more executable instructions for performing a specific logic function. It should also be noted that in some alternative embodiments, the functions described in the block may not appear in order. For example, two blocks shown one by one can actually be performed substantially simultaneously, or these blocks can be performed in reverse order according to the functions they sometimes perform.

[0039] At this moment, the term "~unit" used in the embodiment refers to the software or hardware component that can perform any role, such as FPGA or ASIC. However, "~unit" is not specific to software or hardware. It can be configured to reside on an addressable storage medium, or it can be configured to perform one or more processors. Therefore, in one example, "unit" includes components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and variables such as software components, object-oriented software components, class components and task components. The functions provided in components and "~unit" can be combined into fewer components and "~unit", or further divided into additional components and "~unit". In addition, components and "unit" can be implemented as one or more CPUs in a playback device or a secure multimedia card.

[0040] The operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is considered that the detailed description of the relevant disclosed features or configurations will unnecessarily obscure the essence of the present invention, such detailed description will be omitted. In addition, the following terms are defined in view of their functions in the present invention, and they may vary depending on the intention or custom of the user, operator. Therefore, the definitions should be read in light of the entire specification.

[0041] In the following description of the present invention, if it is deemed that a detailed description of a related disclosed feature or configuration would unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0042] As used in the following description, for the purpose of explanation, terms used to identify access nodes, terms used to refer to network entities, terms used to refer to messages, terms used to refer to interfaces between network entities, terms used to refer to various identification information, and terms used to refer to various identification information are exemplified. Therefore, the present invention is not limited to the terms described herein, and other terms may be used to refer to objects with equivalent technical meanings.

[0043] For the purpose of the following description, the present invention uses the terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard or its variants. However, the present disclosure is not limited by these terms and names and can be equally applicable to systems based on other standards. In the present disclosure, for ease of description, the term eNB can be used interchangeably with gNB, that is, a base station described as an eNB can also refer to a gNB.

[0044] FIG. 1 a is a diagram showing a structure of a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0045] Referring to FIG. 1a, as shown in the figure, the radio access network of the long term evolution (LTE) system is composed of next generation base stations (evolved node B, hereinafter referred to as ENB, node B or base station) 1a-05, 1a-10, 1a-15 and 1a-20, mobility management entity (MME) 1a-25 and serving gateway (S-GW) 1a-30. User equipment (hereinafter referred to as UE or terminal) 1a-35 is connected to the external network through ENB 1a-05 to 1a-20 and S-GW 1a-30.

[0046] In Fig. 1a, ENBs 1a-05 to 1a-20 correspond to conventional Node Bs in a UMTS system. The ENBs are connected to UEs 1a-35 through wireless channels and play a more complex role than conventional Node Bs.

[0047] In LTE systems, all user traffic, including real-time services such as Voice over IP (VoIP) based on Internet Protocol, is served through shared channels. Therefore, it is necessary to aggregate status information such as UE's buffer status, available transmission power status, channel status, etc. and devices that schedule these status information, which is performed by ENB 1a-05 to 1a-20.

[0048] One ENB usually controls multiple cells. In order to achieve a transmission rate of, for example, 100 Mbps, the LTE system uses, for example, orthogonal frequency division multiplexing (hereinafter referred to as OFDM) as a radio access technology in a 20 MHz bandwidth. In addition, an adaptive modulation and coding (AMC) method is applied to determine a modulation scheme and a channel coding rate according to the channel state of the terminal.

[0049] The S-GW 1a-30 is a device that provides a data bearer, and creates or removes a data bearer under the control of the MME 1a-25. The MME is a device that processes various control functions and a mobility management function for a terminal, and is connected to a plurality of base stations.

[0050] FIG. 1 b is a diagram illustrating a radio protocol structure in a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0051] Referring to Figure 1b, the radio protocol of the LTE system consists of packet data convergence protocol (PDCP) 1b-05 and 1b-40 at the terminal and ENB, radio link control (RLC) 1b-10 and 1b-35, and medium access control (MAC) 1b-15 and 1b-30. Packet data convergence protocol (PDCP) 1b-05 and 1b-40 are responsible for operations such as IP header compression / recovery. The main functions of PDCP are summarized as follows:

[0052] -Header compression and decompression: ROHC only

[0053] -Transmission of user data

[0054] - For RLC AM, in-sequence delivery of upper layer PDUs during PDCP re-establishment

[0055] - For split bearer for DC (supports RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[0056] - For RLC AM, duplicate detection of lower layer SDUs during PDCP re-establishment

[0057] - Retransmission function (for split bearer of DC, retransmit PDCP SDU at handover, for RLC AM, retransmit PDCP PDU during PDCP data recovery)

[0058] -Encryption and decryption functions (encryption and decryption)

[0059] - Timer-based SDU deletion functionality (timer-based SDU discard in uplink).

[0060] Radio link control (hereinafter referred to as RLC) 1b-10 and 1b-35 reconfigures a PDCP packet data unit (PDU) into an appropriate size and performs an ARQ operation, etc. The main functions of the RLC are summarized as follows.

[0061] -Transmission of upper layer PDU

[0062] - Error correction via ARQ (for AM data transmission only)

[0063] - RLC SDU splicing, segmentation and reassembly (only for UM and AM data transmission)

[0064] - Re-segmentation of RLC data PDU (only for AM data transmission)

[0065] - Reordering of RLC data PDUs (only for UM and AM data transmission)

[0066] - Duplicate detection (for UM and AM data transmission only)

[0067] -Protocol error detection (for AM data transmission only)

[0068] -RLC SDU discard (only for UM and AM data transmission)

[0069] -RLC re-establishment function.

[0070] MAC (1b-15, 1b-30) is connected to several RLC layer devices configured in a terminal, and performs operations of multiplexing RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows:

[0071] - Mapping between logical channels and transport channels

[0072] - Multiplex / demultiplex MAC SDUs belonging to one or different logical channels into / from transport blocks (TBs) delivered to the physical layer on transport channels

[0073] -Dispatch information report

[0074] - Error correction through HARQ

[0075] - Priority handling between logical channels of a UE

[0076] - Priority handling between UEs through dynamic scheduling

[0077] -MBMS service identification function

[0078] -Transmission format selection function

[0079] - Fill function.

[0080] The physical layers 1b-20 and 1b-25 channel-code and modulate the upper layer data, create OFDM symbols and transmit them to the wireless channel, or demodulate and channel-decode OFDM symbols received through the wireless channel and transfer them to the upper layer.

[0081] FIG. 1c is a diagram showing a structure of a next generation mobile communication system according to an embodiment of the present disclosure.

[0082] Referring to FIG1c, as shown in the figure, the radio access network of the next generation mobile communication system (hereinafter referred to as NR or 2G) includes a new radio node B (hereinafter referred to as NR gNB or NR base station) 1c-10 and a new radio core network (NR CN) 1c-05 and 1c-05. The user terminal (new radio user equipment, NR UE or terminal) 1c-15 is connected to an external network through the NR gNB 1c-10 and the NR CN 1c-05.

[0083] In Figure 1c, NR gNB 1c-10 corresponds to eNB (evolved Node B) in the conventional LTE system. NR gNB is connected to NR UE 1c-15 through a wireless channel and can provide better services than conventional Node B. In the next generation mobile communication system, all user traffic is served through a shared channel, so it is necessary to aggregate state information such as the buffer status of the UE, the available transmission power status, the channel status, etc. and a device for performing scheduling, which is performed by NR NB 1c-10. One NRgNB generally controls multiple cells. In order to achieve ultra-high-speed data transmission compared with conventional LTE, it can have a larger bandwidth than the conventional maximum bandwidth, and can additionally apply beamforming technology using orthogonal frequency division multiplexing (OFDM) as a radio access technology. It also applies an adaptive modulation and coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel conditions of the terminal. NR CN 1c-05 performs functions such as mobility support, bearer configuration, and QoS configuration. NR CN is a device that performs a mobility management function of the terminal and various control functions, and is connected to multiple base stations. The next generation mobile communication system can also interoperate with the conventional LTE system, and the NR CN is connected to the MME 1c-25 through a network interface. The MME is connected to the eNB 1c-30 which is a conventional base station.

[0084] FIG. 1d is a diagram illustrating a wireless protocol structure of a next generation mobile communication system according to an embodiment of the present disclosure.

[0085] FIG. 1d is a diagram showing a radio protocol structure of a next generation mobile communication system to which the present disclosure may be applied.

[0086] Referring to Figure 1d, the wireless protocol of the next generation mobile communication system includes NR SDAP1d-01 and 1d-45, NR PDCP 1d-05 and 1d-40, NR RLC 1d-10 and 1d-35, and NR MAC 1d-15 and 1d-30 at the terminal and the base station respectively.

[0087] The main functions of NR SDAP 1d-01 and 1d-45 may include some of the following functions:

[0088] -Transmission of user plane data

[0089] - Mapping between QoS flows and DRBs for both DL and UL

[0090] - Marking of QoS flow ID in both DL and UL packets for uplink and downlink

[0091] -Reflective QoS flow to DRB mapping for UL SDAP PDU.

[0092] For SDAP layer devices, for each PDCP layer device or each bearer or each logical channel, the terminal can be configured through an RRC message whether to use the header of the SDAP layer device or the function of the SDAP layer device, and in the case where the SDAP header is configured, a 1-bit indicator of NAS QoS reflection configuration (NAS reflection QoS) and a 1-bit indicator of AS QoS reflection configuration (AS reflection QoS) in the SDAP header can be used to instruct the terminal to update or reconfigure the mapping information of the QoS flow and data bearer for the uplink and downlink. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used as data processing priority, scheduling information, etc. to support seamless services.

[0093] The main functions of NR PDCP 1d-05 and 1d-40 may include some of the following functions:

[0094] -Header compression and decompression (ROHC only)

[0095] -Transmission of user data

[0096] - In-sequence delivery of upper layer PDUs

[0097] - Out-of-order delivery of upper layer PDUs

[0098] - Reordering of received PDCP PDUs

[0099] - Duplicate detection of lower layer SDU

[0100] -Retransmission of PDCP SDU

[0101] -Encryption and decryption functions (encryption and decryption)

[0102] - Timer based SDU discard in uplink.

[0103] In the above, the reordering function of the NR PDCP device refers to a function of reordering the PDCP PDUs received from the lower layer in sequence based on the PDCP sequence number (SN), and may include a function of delivering the data to the upper layer in the reordered order, or may include a function of delivering immediately regardless of the order, may include a function of recording lost PDCP PDUs by reordering, may include a function of reporting the status of lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of lost PDCP PDUs.

[0104] NR RLC 1d-10 and 1d-35 may include some of the following functions.

[0105] -Transmission of upper layer PDU

[0106] - In-sequence delivery of upper layer PDUs

[0107] - Out-of-order delivery of upper layer PDUs

[0108] - Error correction via ARQ

[0109] - RLC SDU splicing, segmentation and reassembly

[0110] - Re-segmentation of RLC data PDUs

[0111] - Reordering of RLC data PDUs

[0112] - Duplicate detection function

[0113] -Protocol error detection

[0114] -RLC SDU discarded

[0115] -RLC reconstruction function

[0116] In the above, the in-sequence delivery function of the NR RLC device refers to a function of delivering the RLC SDU received from the lower layer to the upper layer in sequence, and may include a function of reassembling and delivering a single RLC SDU when it is initially separated into multiple RLC SDUs and received, may include a function of reordering the received RLC PDUs based on the RLC SN (sequence number) or the PDCP SN (sequence number), may include a function of recording the lost RLC PDU in the reordered sequence, may include a function of reporting the status of the lost RLC PDU to the transmitting side, may include a function of requesting retransmission of the lost RLC PDU, may include a function of delivering only the RLC SDU (if any) before the lost RLC SDU to the upper layer in sequence, or if a predetermined timer has expired for the lost RLC SDU, may include a function of delivering all RLC SDUs received before the timer is started to the upper layer in sequence, or if a predetermined timer has expired for the lost RLC SDU, may include a function of delivering all RLC SDUs received so far to the upper layer in sequence even if there is a lost RLC SDU.

[0117] In addition, in the above, the NR RLC layer may also process the RLC PDUs in the order in which they are received (i.e., in the order of arrival, regardless of the sequence number), and deliver them to the PDCP device in an out-of-order delivery manner, or, in the case of segmentation, may receive segments stored in a buffer or to be received at a later time, reconstruct them into a complete RLC PDU, and process and deliver them to the PDCP device. The NR RLC layer may not include a splicing function, and the function may be performed by the NR MAC layer or replaced by a multiplexing function of the NR MAC layer.

[0118] In the above, the out-of-order delivery function of the NR RLC device refers to a function of directly delivering the RLC SDU received from the lower layer to the upper layer without considering the order, and may include a function of reassembling and delivering the RLC SDU when it is originally separated into multiple RLC SDUs and received, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDU, sorting, and recording lost RLC PDUs.

[0119] NR MAC 1d-15 and 1d-30 can be connected to multiple NR RLC layer devices configured in one terminal. The main functions of NR MAC may include some of the following functions:

[0120] - Mapping between logical channels and transport channels

[0121] -Multiplexing / demultiplexing of MAC SDU

[0122] -Scheduling information reporting function

[0123] - Error correction through HARQ

[0124] - Priority handling between logical channels of a UE

[0125] - Priority handling between UEs through dynamic scheduling

[0126] -MBMS service identification function

[0127] -Transmission format selection function

[0128] -filling.

[0129] NR PHY layers 1d-20 and 1d-25 can perform operations of channel coding and modulating upper layer data, creating OFDM symbols and sending them through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and passing them to an upper layer.

[0130] FIG. 1e is a flowchart of a process for performing a general handover operation in a mobile communication system according to an embodiment of the present disclosure.

[0131] The terminal 1e-05 receives an RRC message including measurement configuration information from the source cell 1e-10 (1e-25).

[0132] The terminal 1e-05 applies the measurement configuration information to measure the signal quality of the serving cell and the neighboring cells, and reports the collected cell measurement information to the source cell 1e-10 periodically or when a predetermined event occurs (1e-30) (1e-35).

[0133] The source cell 1e-10 determines whether to trigger a general handover operation (1e-40) based on the reported cell measurement information. For example, if event A3 (neighbor becomes offset better than SpCell) is satisfied and cell measurement information is reported, the source cell 1e-10 may determine a general handover.

[0134] If it is decided to trigger a general handover, the source cell 1e-10 requests a general handover to a target cell 1e-20 through a predetermined inter-node message (1e-45).

[0135] The target cell 1e-20 having received the request accepts the request and sends handover configuration information or additional configuration information required for a general handover operation to the source cell 1e-10 (1e-50).

[0136] The source cell 1e-10 stores the handover configuration information or additional configuration information received from the target cell 1e-20 in a predetermined RRC message, and sends the RRC message to the terminal (if the source cell is an NR cell, it is an RRCReconfiguration message; if the source cell is an LTE cell, it is an RRCConnectionReconfiguration message) (1e-55).

[0137] The handover configuration information (e.g., ReconfigWithSync in NR; MobilityControlInfo in LTE) may include the ID of the target cell, frequency information, configuration information required for random access operation of the target cell (dedicated preamble information, dedicated radio resource information, etc.), transmission power information, C-RNTI information used in the target cell, T304 timer value, etc.

[0138] When receiving the handover configuration information, the terminal 1e-05 immediately starts a random access process to the target cell 1e-20 and starts the T304 timer (1e-60). At the same time, the data transmission and reception with the serving cell are stopped.

[0139] In case the terminal 1e-05 receives a dedicated preamble in step 1e-55, it may send a dedicated preamble (1e-70). In case no dedicated preamble is provided, one of the preambles used on a contention basis may be sent.

[0140] The target cell 1e-20 receiving the preamble sends a random access response (RAR) message (1e-75) to the terminal 1e-05.

[0141] The terminal 1e-05 uses the UL grant information stored in the RAR and transmits msg3 to the target cell 1e-20 (1e-80).

[0142] msg3 stores an RRCConnectionReconfigurationComplete message in the case of an LTE system, and stores an RRCReconfigurationComplete message in the case of an NR system. When the random access procedure is successfully completed, the general handover is considered to have been successfully completed, and the running T304 timer is stopped.

[0143] If the general handover is not successfully completed until the T304 timer expires, it is considered a handover failure, and the terminal can declare RLF, store the handover failure information in the VarRLF-Report variable, revert to the configuration used in the source primary cell (source PCell), and initiate a connection reestablishment process with the source PCell.

[0144] For reference, the terminal may store the handover failure information in the VarRLF-Report variable as follows.

[0145] [Table 1]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152] FIG. 1f is a diagram illustrating a process of using a dual active protocol stack (DAPS) in performing a handover according to an embodiment of the present disclosure.

[0153] When performing a general handover, upon receiving the handover configuration information, the terminal stops sending and receiving data to and from the source cell, and after the handover process is successful, starts sending and receiving data to and from the target cell. Therefore, an interruption time occurs during the time interval when data transmission and reception cannot be performed. If the terminal has a dual-active protocol stack, data transmission and reception with the source cell can be maintained during the time interval.

[0154] In the present disclosure, the handover taking into account the above-mentioned terminal capabilities is referred to as dual active protocol stack (DAPS) handover. When DAPS handover is established, the terminal can receive downlink data from the source cell and the target cell at the same time. However, due to insufficient terminal transmission power or signal interference, simultaneous uplink data transmission to the source cell and the target cell is only possible when certain conditions are met.

[0155] In order to minimize terminal complexity, when DAPS handover is performed, uplink data transmission is possible through only one link, and the uplink where data transmission occurs can be switched from the source cell to the target cell at a specific point in time.

[0156] The activation states of the dual protocol stacks and the terminal operations corresponding to the source cell and the target cell are different at each major specific time point.

[0157] Before performing the handover (1f-05), the terminal only uses the protocol stack corresponding to the source cell.

[0158] After the DAPS handover configuration information is provided to the terminal and before the RACH to the target cell is performed (1f-10), when the DAPS handover configuration information is provided to the terminal through the RRCReconfiguration message, the terminal configures the protocol stack corresponding to the target cell. However, the terminal still only utilizes the protocol stack corresponding to the source cell. The protocol stack corresponding to the target cell may be inactive.

[0159] During the random access channel (RACH) execution interval (1f-15), when the random access channel (RACH) operation is initiated, at least the PHY layer and the medium access control (MAC) layer in the protocol stack corresponding to the target cell are activated to perform the RACH operation. At this time, the terminal still maintains data transmission and reception with the source cell.

[0160] When the time comes for the terminal to send a HO success completion message to the target cell 1f-20, the terminal shall have at least some functions of the PHY layer, MAC layer, RLC layer, and Packet Data Convergence Control (PDCP) layer enabled in the protocol stack corresponding to the target cell, and shall process the HO success completion message as a signaling radio bearer. The terminal may send uplink data to the source cell, at least until the HO success completion message is sent to the target cell.

[0161] After the terminal receives the RAR from the target cell (1f-25), both dual-active protocol stacks are activated. The terminal maintains data transmission and reception with the source cell until a certain point in time after receiving the RAR. In addition, the point in time at which the terminal can maintain downlink data reception with the source cell and the point in time at which the terminal can maintain uplink data transmission may be different. The terminal can send uplink data to the source cell until it sends a HO success completion message to the target cell, but can continue to receive downlink data thereafter.

[0162] After the terminal releases the source cell 1f-30, the protocol stack corresponding to the source cell is also released. From now on, the terminal only uses the protocol stack corresponding to the target cell.

[0163] FIG. 1g is a flow chart of a process for performing a dual active protocol stack (DAPS) switch according to an embodiment of the present disclosure.

[0164] The terminal 1g-02 may switch to a connection mode (1g-12) with the source base station 1g-04 through an RRC establishment or RRC recovery process.

[0165] The terminal with DAPS switching support capability may report to the source base station 1g-04 that it supports DAPS switching (1g-14).

[0166] The source base station 1g-04 can use the RRC connection reconfiguration message (RRCReconfiguration in NR, RRCConnectionReconfiguration in LTE) to configure the measurement configuration for the terminal 1g-02 for mobility support purposes (1g-16).

[0167] When the measurement report event is triggered (1g-18), the terminal 1g-02 may report a measurement report to the base station 1g-04 (1g-20).

[0168] The source base station 1g-04 that has received the measurement report may decide to perform handover with a specific neighboring base station based on the cell measurement information included in the measurement report (1g-22).

[0169] In addition, the source base station 1g-04 may send a handover request message to the target base station 1g-06, and the target base station 1g-06 may send a response message to the source base station 1g-04 (1g-24).

[0170] The handover request message may include an indicator indicating that the terminal will perform DAPS handover. The response message may include handover configuration information or additional configuration information for the terminal.

[0171] The source base station 1g-04 may store the handover configuration information or additional configuration information received from the target base station 1g-06 in a predetermined RRC message, and may send the predetermined RRC message (RRCReconfiguration message if the source base station is an NR cell; RRCConnectionReconfiguration message if the source base station is an LTE cell) to the terminal (1g-26). The handover configuration information (e.g., ReconfigWithSync in NR, MobilityControlInfo in LTE) may include the ID of the target cell, frequency information, configuration information required for random access operations for the target cell (dedicated preamble information, dedicated radio resource information, etc.), transmission power information, C-RNTI information used by the target cell, T304 timer value or a timer value similar to T304, etc.

[0172] The terminal 1g-02 having received the handover configuration information may run T304 or a timer similar to T304 and perform random access to the target cell 1g-06 (1g-36).

[0173] When the timer expires, if the terminal does not successfully send an RRC connection reconfiguration message to the target cell 1g-06, the handover can be considered to have failed. If the terminal believes that the handover has failed (when the T304 timer expires and any DAPS bearer is configured to the terminal), and a radio link failure is detected at the source base station, the terminal can revert to the configuration used in the source PCell / base station, store the handover failure information in the VarRLF-Report variable, and initiate the process of reestablishing the RRC connection with the source cell.

[0174] For reference, the method in which the terminal stores the handover failure information in the VarRLF-Report variable may follow the above embodiment.

[0175] If the source base station does not detect a radio link failure, (if the T304 timer has expired and any DAPS bearers have been configured on the terminal) the terminal may consider that the handover has failed and send a failureInformation message with daps-failure to the source base station to report the failure of the DAPS handover.

[0176] In step 1g-26, the RRC connection reconfiguration message may include an indicator indicating that this is a handover using DAPS. The terminal 1g-02 that has received the indicator may maintain data transmission and reception with the source cell until a certain point even after sending the first preamble to the target cell 1g-06 (1g-28 and 1g-34).

[0177] The terminal user data sent and received through the source cell can be delivered to the end user (1g-30) through UPF / S-WG 1g-08.

[0178] The source cell 1g-04 may forward the downlink data of the terminal to the target cell 1g-06 (1g-32). This is because the signal quality of the link with the source cell may deteriorate rapidly, making it difficult to send and receive data.

[0179] When terminal 1g-02 receives a random access response message from the target cell 1g-06, it can send an RRC connection reconfiguration completion message (RRCReconfiguratonComplete message in NR, RRCConnectionReconfigurationComplete message in LTE) to the target cell 1g-06 (1g-38).

[0180] If the RRC message is successfully sent, it means that the handover to the target cell has been successfully completed. Terminal 1g-02 performs uplink data transmission with the source cell until the RRC message is successfully sent.

[0181] When the terminal 1g-02 receives a UL grant (uplink scheduling information) from the target cell 1g-06, it can switch the uplink to the target cell.

[0182] The target cell 1g-06 having received the RRC connection reconfiguration complete message may decide to disconnect the terminal from the source cell (1g-40).

[0183] The target cell 1g-06 may request the source cell 1g-04 to disconnect (1g-42).

[0184] The source cell 1g-04 having received the request may stop sending and receiving data to and from the terminal 1g-02. The source cell 1g-04 may provide an SN state transfer to the target cell 1g-06 (1g-44). This information may be used to smoothly send and receive data between the target cell and the terminal.

[0185] The target cell 1g-06 may instruct the terminal 1g-02 to disconnect from the source cell using a predetermined RRC message (1g-46).

[0186] The terminal 1g-02 having received the message may disconnect from the source cell (1g-52) and send a response message to the message (1g-48). As another option, the terminal may implicitly disconnect from the source cell when the terminal successfully sends the RRC connection reconfiguration complete message to the target cell or after a predetermined offset time.

[0187] In this embodiment, if a radio link failure with the source cell is detected during DAPS HO, and the handover from the target cell fails (ie, the T304 timer expires), the terminal may store the handover failure information in the VarRLF-Report variable. At this time, the base station cannot distinguish whether the handover failure information stored in the VarRLF-Report variable is due to a general handover failure or due to a DAPS handover failure.

[0188] FIG1h is a flowchart of terminal operations after a dual active protocol stack (DAPS) switching failure according to an embodiment of the present disclosure.

[0189] Referring to FIG. 1h , the terminal may be in an RRC connected mode ( 1h - 05 ).

[0190] In step 1h-10, the terminal may send a terminal capability information message (UECapabilityInformation) to the source base station. The message may report support for DAPS switching to the source base station. In the present disclosure, the message may include an indicator that the switching failure information may not be stored in the Var-RLF-Report variable when a subsequent DAPS switching fails.

[0191] - When the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell

[0192] In steps 1h-15, the terminal may perform DAPS HO, that is, the terminal has a daps bearer configured by the base station.

[0193] In step 1h-20, the terminal may determine that the T304 timer associated with the target cell has expired and that a radio link failure has occurred (or detected) in the source PCell.

[0194] In step 1h-25, as described above in step 1h-10, when the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell, the terminal can determine whether the target cell has the ability to not store the handover failure information in the Var-RLF-Report variable.

[0195] In step 1h-30, when the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell, the terminal may reapply the configuration information used by the source PCell and initiate a connection reestablishment procedure, assuming that the terminal has the capability of not storing the handover failure information in the Var-RLF-Report variable. In this case, the terminal may not store the handover failure information in the Var-RLF-Report variable.

[0196] In step 1h-35, when the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell, if the terminal does not have the ability to not store the switching failure information in the Var-RLF-Report variable, the terminal can reapply the configuration information used by the source PCell, store the switching failure information in the VarRLF-Report variable, and initiate a connection reestablishment process.

[0197] In the present disclosure, if the T304 timer expires during DAPS HO failure and a radio link failure occurs in the source PCell, the terminal may not report RLF information to the base station. On the other hand, if a general HO failure occurs, the terminal may report RLF information to the base station.

[0198] FIG. 1i is a flowchart of terminal operations after a dual active protocol stack (DAPS) switching failure according to an embodiment of the present disclosure.

[0199] Referring to FIG. 1i , the terminal may be in an RRC connected mode ( 1i - 05 ).

[0200] In step 1i-10, the terminal may send a terminal capability information message (UECapabilityInformation) to the source base station. The message may report to the source base station that it supports DAPS switching. In the present disclosure, the message may include information or an indicator that the source base station has the ability to include information in the Var-RLF-Report variable to indicate a subsequent DAPS switching failure. Alternatively, in the present disclosure, the message may include an indicator that the message has the ability to include information in a predetermined RRC message (e.g., RRCReestablishmentComplete) to indicate a subsequent DAPS switching failure.

[0201] - When the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell

[0202] In step 1i-15, the terminal may perform DAPS HO, that is, the terminal has a daps bearer configured by the base station.

[0203] In step 1i-20, the terminal may determine that the T304 timer associated with the target cell has expired and that a radio link failure has occurred (or detected) in the source PCell.

[0204] In step 1i-25, as described above in step 1i-10, the terminal can determine that when the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell, the terminal has the ability to include information indicating this in the Var-RLF-Report variable, or include an indicator indicating this in a predetermined RRC message.

[0205] In step 1i-30, when the T304 timer associated with the target cell expires and a radio link failure occurs in the source PCell, the terminal may store information indicating this in the Var-RLF-Report variable. That is, it may include an indicator indicating that the T304 timer has expired and a radio link failure has occurred in the source Pcell or corresponding daps-failure information. The terminal may reapply the configuration information used by the source PCell and initiate a connection reestablishment process. The terminal may also send a predetermined RRC message (e.g., RRCReestablishmentComplete) to the base station, which includes an indicator indicating that the T304 timer has expired and a radio link failure has occurred on the source PCell.

[0206] In step 1i-35, when the T304 timer associated with the target cell expires and a radio link failure occurs in the source Pcell, if the terminal is unable to store information indicating this in the Var-RLF-Report variable or is unable to include an indicator indicating this in a predetermined RRC message, it can reapply the configuration information used by the source PCell, store the switching failure information in the Var-RLF-Report variable, and initiate a connection reestablishment process, as shown in the embodiment of Figure 1e.

[0207] In step 1i-40, the terminal may receive a UEInformationRequest message from the base station. The message may include an indicator for reporting an RLF report (rlf-ReportReq).

[0208] In step 1i-45, the terminal may send a UEInformationResponse message including RLF information to the base station. The message may include information from VarRLF-Report.

[0209] FIG. 1j is a flowchart of operations of a terminal and a base station managing conflict if there are multiple gaps having the same priority according to an embodiment of the present disclosure.

[0210] Referring to Figure 1j, in step 1j-15, the terminal (UE) 1j-05 can establish an RRC connection with the base station 1j-10 and be in RRC connection mode (1j-15).

[0211] In step 1j-20, the terminal 1j-05 may send a UECapabilityInformation message to the base station 1j-10. The message may include at least one of the following:

[0212] - Indicators of the same priority may be supported for one or more gap configuration messages

[0213] - When one or more gap configuration information having the same priority overlap (collide) on the time axis, an indicator that specific gap configuration information may be applied as a priority according to an instruction of the base station.

[0214] - When one or more gap configuration information with different priorities conflict on the time axis, an indicator that specific gap configuration information may be applied as a priority according to an instruction of the base station.

[0215] In step 1j-25, the base station 1j-10 may send a predetermined RRC message (e.g., RRC Resume (RRC Recovery) or RRC Reconfiguration) containing one or more gap configuration information to the terminal 1j-05.

[0216] The gap configuration information may refer to gap configuration information that can be configured for a terminal, such as measurement gap configuration information, MUSIM gap configuration information used by a terminal supporting a multi-universal subscriber identity module (MUSIM), positioning gap configuration information, non-terrestrial network gap configuration information used by a terminal supporting satellite services, etc. Of course, the gap configuration information may not be limited to the above-mentioned gap configuration information mentioned in the present disclosure. For example, the gap configuration information may have the following ASN.1 structure.

[0217] -Measurement gap configuration information or location measurement gap configuration information

[0218] [Table 2]

[0219]

[0220]

[0221]

[0222] MUSIM gap configuration information

[0223] in,

[0224] :

[0225] IE MeasGapConfig specifies the measurement gap configuration and controls the setup / release of the measurement gap.

[0226] :MeasGapConfig information element

[0227]

[0228] Gap configuration information used by terminals supporting satellite services

[0229] in,

[0230] :

[0231] IE MUSIM-GapConfig specifies the MUSIM gap configuration and controls the setup / release of the MUSIM gap.

[0232] :MUSIM-GapConfig information element

[0233]

[0234]

[0235]

[0236]

[0237]

[0238] in,

[0239] :

[0240] IE MeasObjectNR specifies information applicable to SS / PBCH block intra / inter-frequency measurements and / or CSI-RS intra / inter-frequency measurements.

[0241] :MeasObjectNR information element

[0242] The base station 1j-10 can configure the gap priority value associated with each gap configuration information to the terminal 1j-05.

[0243] In an example, the gap priority value may include a value of one of integer values ​​from 1 to 16. If the gap priority value is not configured in the specific gap configuration information, the terminal may determine that the gap has the lowest priority. The purpose of the gap priority value is to allow the terminal to apply specific gap configuration information (e.g., with a higher gap priority value, or apply a specific gap as instructed by the base station) when multiple gaps overlap on the time axis.

[0244] Base station 1j-10 can configure multiple gap configuration information with the same gap priority value to terminal 1j-05.

[0245] Specifically, the base station 1j-10 can configure the same gap priority value in multiple gap configuration information to the terminal only when multiple gaps do not overlap on the time axis, or the base station 1j-10 can configure the same gap priority value in multiple gap configuration information to the terminal even when multiple gaps overlap on the time axis.

[0246] In step 1j-30, terminal 1j-05 may perform operations according to the gap configuration information received in step 1j-25.

[0247] In step 1j-35, terminal 1j-05 can determine that multiple gaps configured by the base station can overlap on the time axis. Terminal 1j-05 can give priority to gaps with higher gap priority values ​​and perform operations according to the gap configuration information.

[0248] In step 1j-40, the base station 1j-10 may send a predetermined RRC message (e.g., RRCReconfiguration) or MAC CE or DCI to instruct the terminal 1j-05 to apply a specific gap. This is so that when multiple gaps overlap on the time axis, the terminal uses some gap configuration information to perform gap operations.

[0249] Specifically, when multiple gaps with the same gap priority value overlap on the time axis, the base station 1j-10 can send a predetermined RRC message (e.g., RRCReconfiguration) or MAC CE or DCI to the terminal to apply a specific gap. Of course, when multiple gaps overlap on the time axis, the base station 1j-10 can send a predetermined RRC message (e.g., RRCReconfiguration) or MAC CE or DCI to the terminal 1j-05 to use a gap with a lower gap priority.

[0250] The base station may instruct the terminal to apply the specific gap in a one-shot at a specific time without changing the configured gap priority value, or it may instruct the terminal to apply the specific gap by changing the gap priority value.

[0251] In step 1j-45, the terminal 1j-05 may perform operations according to the gap configuration information indicated by the base station 1j-10 in step 1j-40.

[0252] FIG. 1k is a flowchart of an operation of a terminal and a base station managing a conflict if there are a plurality of gaps having the same priority according to another embodiment of the present disclosure.

[0253] Referring to Figure 1k, in step 1k-15, the terminal 1k-05 can establish an RRC connection with the base station 1k-10 and is in RRC connection mode (1k-15).

[0254] In step 1k-20, the terminal (UE) 1k-05 may send a UECapabilityInformation message to the base station 1k-10. The message may include at least one of the following:

[0255] - Indicators of the same priority may be supported for one or more gap configuration messages

[0256] - When one or more gap configuration information having the same priority overlap (collide) on the time axis, an indicator that specific gap configuration information may be applied as a priority according to an instruction of the base station.

[0257] - When one or more gap configuration information with different priorities conflict on the time axis, an indicator that specific gap configuration information may be applied as a priority according to an instruction of the base station.

[0258] -When one or more gap configuration information with the same priority or different priorities overlap on the time axis, an indicator may indicate a preference for applying a specific gap information with priority. This may also be indicated by a gap characteristic. The gap characteristic refers to the gap capability of each terminal capability, such as MUSIM gap configuration information and location measurement gap configuration information, but does not indicate each gap configuration information.

[0259] In step 1k-25, the base station 1k-10 may send a predetermined RRC message (e.g., RRCResume or RRCReconfiguration) containing one or more gap configuration information to the terminal 1k-05.

[0260] The gap configuration information may refer to gap configuration information that can be configured for a terminal, such as measurement gap configuration information, MUSIM gap configuration information used by a terminal supporting a multi-universal subscriber identity module (MUSIM), positioning gap configuration information, non-terrestrial network gap configuration information used by a terminal supporting satellite services, etc. Of course, the gap configuration information may not be limited to the above-mentioned gap configuration information mentioned in the present disclosure. The gap configuration information may follow the above-mentioned embodiments.

[0261] The base station 1k-10 may configure the gap priority value associated with each gap configuration information to the terminal.

[0262] In an example, the gap priority value may include a value of one of integer values ​​from 1 to 16. If the gap priority value is not configured in the specific gap configuration information, the terminal may determine that the gap has the lowest priority. The purpose of the gap priority value is to allow the terminal to apply specific gap configuration information (e.g., with a higher gap priority value, or apply a specific gap as instructed by the base station) when multiple gaps overlap on the time axis.

[0263] The base station 1k-10 can configure multiple gap configuration information with the same gap priority value to the terminal 1k-05.

[0264] Specifically, the base station can configure the same gap priority value in multiple gap configuration information to the terminal only when multiple gaps do not overlap on the time axis, or even when multiple gaps overlap on the time axis, the base station can configure the same gap priority value in multiple gap configuration information to the terminal.

[0265] In step 1k-25, the base station 1k-10 may send a predetermined RRC message (e.g., RRCResume or RRCReconfiguration) to the terminal 1k-05 to send the terminal's preferred gap priority value.

[0266] For example, the predetermined RRC message may include otherConfig configuration information. The otherConfig configuration information may include an inhibit timer. The purpose of the inhibit timer is that when the terminal sends a message including a preferred gap priority value to the base station, or initiates a process of sending a message including a preferred gap priority value, the terminal will trigger the inhibit timer and will not resend the preferred gap priority value until the triggered inhibit timer expires.

[0267] In step 1k-30, terminal 1k-05 may perform operations according to the gap configuration information received in step 1k-25.

[0268] In step 1k-35, the terminal 1k-05 may determine that multiple gaps configured by the base station may overlap on the time axis. The terminal 1k-05 may give priority to gaps with higher gap priority values ​​and perform operations according to the gap configuration information. If multiple gaps with the same gap priority value overlap on the time axis, the terminal 1k-05 may give priority to gaps with longer gap application periods (gap lengths or gap periods), or perform gap operations by sequentially applying one gap.

[0269] In step 1k-40, the terminal 1k-05 may send a predetermined RRC message (eg, UEAssistanceInformation) or MACCE including a preferred gap priority value for each gap configuration information to the base station 1k-10.

[0270] Alternatively, when multiple gaps with the same gap priority value overlap on the time axis, the terminal 1k-05 can send a predetermined RRC message (e.g., UEAssistanceInformation) or MAC CE containing a preference for applying a specific gap to the base station.

[0271] Of course, even when multiple gaps with different gap priority values ​​overlap on the time axis, the terminal 1k-05 can send a predetermined RRC message or MACCE to the base station containing a preference for applying gaps with lower gap priority values. For reference, after executing step 1k-40, the terminal can perform gap operations by immediately prioritizing or applying gaps with specific preferences, or it can perform gap operations according to the configuration of the base station after step 1k-45.

[0272] In step 1k-45, the base station 1k-10 may send a predetermined RRC message (e.g., RRCReconfiguration) or MAC CE or DCI instructing the terminal to apply a specific gap according to the terminal 1k-05 gap preference received in step 1k-40, or to change the gap priority value of each gap configuration information.

[0273] In step 1k-50, the terminal 1k-05 may perform operations according to the gap configuration information indicated by the base station 1k-10 in step 1k-45.

[0274] FIG. 11 is a block diagram showing an internal structure of a terminal according to an embodiment of the present disclosure.

[0275] Referring to the above drawings, the terminal includes a radio frequency (RF) processing unit 11-10, a baseband processing unit 11-20, a storage unit 11-30 and a control unit 11-40.

[0276] The RF processing unit 11-10 performs functions such as frequency band conversion and signal amplification for transmitting and receiving signals through a wireless channel. That is, the RF processing unit 11-10 up-converts the baseband signal provided by the baseband processing unit 11-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal.

[0277] For example, the RF processing unit 11-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like.

[0278] In the figure, only one antenna is shown, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit 11-10 may include multiple RF chains. In addition, the RF processing unit 11-10 may perform beamforming. For beamforming, the RF processing unit 11-10 may adjust the phase and amplitude of each of the signals sent and received by multiple antennas or antenna elements. In addition, the RF processing unit may perform MIMO and may receive multiple layers when performing MIMO operations.

[0279] The baseband processing unit 11-20 performs the conversion function between the baseband signal and the bit stream according to the physical layer standard of the system.

[0280] For example, when transmitting data, the baseband processing unit 11-20 generates complex symbols by encoding and modulating the transmission bit stream. In addition, when receiving data, the baseband processing unit 11-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 11-10.

[0281] For example, in the case of following the OFDM (Orthogonal Frequency Division Multiplexing) method, when transmitting data, the baseband processing unit 1l-20 generates complex symbols by encoding and modulating the transmission bit stream, and transmits the complex symbols to the subcarrier. After mapping, the OFDM symbol is configured by IFFT (Inverse Fast Fourier Transform) operation and CP (Cyclic Prefix) insertion. In addition, when receiving data, the baseband processing unit 1l-20 divides the baseband signal provided from the RF processing unit 1l-10 into OFDM symbols and maps them to the subcarrier by Fast Fourier Transform (FFT). After recovering the received signal, the received bit stream is recovered by demodulation and decoding.

[0282] The baseband processing unit 11-20 and the RF processing unit 11-10 transmit and receive signals as described above. Therefore, the baseband processing unit 11-20 and the RF processing unit 11-10 can be referred to as a transmitting unit, a receiving unit, a transceiver or a communication unit.

[0283] In addition, at least one of the baseband processing unit 11-20 and the RF processing unit 11-10 may include multiple communication modules to support a variety of different radio access technologies.

[0284] In addition, at least one of the baseband processing unit 11-20 and the RF processing unit 11-10 may include different communication modules for processing signals in different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., IEEE 802.11), cellular networks (e.g., LTE), etc. In addition, different frequency bands may include super high frequency (SHF) bands (e.g., 2.NRHz, NRhz) and millimeter wave (mm-wave) bands (e.g., 60 GHz), etc.

[0285] The storage unit 11-30 stores data for the operation of the terminal, such as basic programs, applications, and configuration information. Specifically, the storage unit 11-30 can store information related to a second access node that performs wireless communication using a second radio access technology. And the storage unit 11-30 provides the stored data according to a request of the control unit 11-40.

[0286] The control unit 11-40 controls the overall operation of the terminal. For example, the control unit 11-40 sends and receives signals through the baseband processing unit 11-20 and the RF processing unit 11-10. In addition, the control unit 11-40 writes and reads data to the storage unit 11-30. To this end, the control unit 11-40 may include at least one processor. For example, the control unit 11-40 may include a communication processor (CP) that performs communication control and an application processor (AP) that controls an upper layer such as an application.

[0287] FIG. 1m is a block diagram showing the structure of a base station according to an embodiment of the present disclosure.

[0288] As shown in the figure, the base station is configured to include an RF processing unit 1m-10, a baseband processing unit 1m-20, a backhaul communication unit 1m-30, a storage unit 1m-40 and a control unit 1m-50.

[0289] The RF processing unit 1m-10 performs functions for transmitting and receiving signals through a wireless channel, such as frequency band conversion and amplification of the signal. That is, the RF processing unit 1m-10 up-converts the baseband signal provided from the baseband processing part 1m-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal.

[0290] For example, the RF processing unit 1m-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In the figure, only one antenna is shown, but the first access node may be equipped with a plurality of antennas.

[0291] Furthermore, the RF processing unit 1m-10 may include a plurality of RF chains. Furthermore, the RF processing unit 1m-10 may perform beamforming.

[0292] For beamforming, the RF processing unit 1m-10 can adjust the phase and size of each signal sent and received through multiple antennas or antenna elements. The RF processing unit can perform downlink MIMO operations by transmitting one or more layers.

[0293] The baseband processing unit 1m-20 performs a conversion function between a baseband signal and a bit stream according to a physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processing unit 1m-20 generates complex symbols by encoding and modulating the transmission bit stream.

[0294] In addition, when receiving data, the baseband processing unit 1m-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 1m-10. For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit 1m-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and constructs OFDM symbols through IFFT operation and CP insertion.

[0295] In addition, when receiving data, the baseband processing unit 1m-20 divides the baseband signal provided from the RF processing unit 1m-10 into OFDM symbols, and recovers the signal mapped to the subcarrier through FFT operation. Thereafter, the received bit stream is recovered through demodulation and decoding. The baseband processing unit 1m-20 and the RF processing unit 1m-10 send and receive signals as described above. Therefore, the baseband processing unit 1m-20 and the RF processing unit 1m-10 can be referred to as a transmitting unit, a receiving unit, a transceiver, a communication unit, or a wireless communication unit.

[0296] The backhaul communication unit 1m-30 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 1m-30 converts a bit stream sent from the main base station to another node (e.g., a secondary base station, a core network, etc.) into a physical signal, and converts a physical signal received from another node into a bit stream.

[0297] The storage unit 1m-40 stores data used for the operation of the main base station, such as basic programs, applications, and configuration information. Specifically, the storage unit 1m-40 may store information about the bearer assigned to the connected terminal, the measurement results reported from the connected terminal, etc. In addition, the storage unit 1m-40 may store information used as a criterion for determining whether to provide or suspend multiple connections to the terminal. And the storage unit 1m-40 provides the stored data according to the request of the control unit 1m-50.

[0298] The control unit 1m-50 controls the overall operation of the main base station. For example, the control unit 1m-50 sends and receives signals through the baseband processing unit 1m-20 and the RF processing unit 1m-10 or through the backhaul communication unit 1m-30. In addition, the control unit 1m-50 records and reads data from the storage unit 1m-40. To this end, the control unit 1m-50 may include at least one processor.

[0299] The embodiments of the present disclosure disclosed in this specification and the accompanying drawings are provided only as specific examples to easily explain the technical content of the present disclosure and facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. It is clear to those skilled in the art that in addition to the embodiments disclosed herein, other modifications based on the technical concept of the present disclosure may also be implemented.

[0300] The methods according to the embodiments described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0301] When implemented as 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 to be executable (configured for execution) by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute the method according to the embodiments described in the claims or description of the present disclosure.

[0302] These programs (software modules, software) can be stored in random access memory (RAM), non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage device, compact disk-ROM (CD-ROM), digital versatile disk (DVD) or other forms of optical storage device, cassette tape. Alternatively, they can be stored in a memory composed of some or all of these. In addition, each of the constituent memories can include multiple copies.

[0303] In addition, the program can be stored on an attachable storage device that can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or any combination thereof. Such a storage device can be accessed by a device executing an embodiment of the present disclosure through an external port. In addition, a separate storage device on a communication network can be accessed by a device executing an embodiment of the present disclosure.

[0304] At the same time, the embodiments disclosed in the above description and the accompanying drawings are provided only as specific examples to easily explain the contents of the present disclosure and help understanding, and are not intended to limit the scope of the present disclosure. Therefore, in addition to the embodiments disclosed herein, the scope of the present disclosure should be interpreted as including all changes or modifications derived from the technical concept of the present disclosure. In addition, as required, each of the above embodiments can be combined with each other to operate.

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: receiving measurement configuration information from a base station, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; determining which of the plurality of measurement gaps to apply; as well as The measuring operation is performed by applying the determined measurement gap.

2. The method according to claim 1, wherein: The determining step is configured to include: receiving a first control message from a base station indicating application of a specific gap; and Based on the first control message, it is determined which measurement gap to apply, wherein The control message includes at least one of a Radio Resource Control (RRC) message, Downlink Control Information (DCI), and a Medium Access Control (MAC) Control Element (CE).

3. The method according to claim 1, characterized in that The method comprises sending a terminal capability information message including terminal capability information to a base station, wherein The terminal capability information includes at least one of the following: An indicator indicating whether multiple measurement gaps with overlapping timelines and having the same priority can be supported; or An indicator indicating that specific gap information among the plurality of measurement gaps can be applied according to an instruction from a base station.

4. The method according to claim 1, wherein: The determining step is configured to include: sending a second control message to a base station, the second control message including a preference for a specific measurement gap among a plurality of measurement gaps having overlapping timelines and having the same priority; receiving a third control message from a base station, the third control message comprising information about which measurement gap to apply based on the preference; and Based on the third control message, it is determined which measurement gap is to be applied.

5. The method according to claim 1, wherein: The determining step is configured to include determining to apply a measurement gap having a long gap application period (gap length or gap period) or determining to sequentially apply one measurement gap.

6. A method performed by a base station in a wireless communication system, the method comprising: generating measurement configuration information to a terminal, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; Sending measurement configuration information including the multiple measurement gaps; as well as A fourth control message indicating that the specific gap is applied is sent to the terminal.

7. The method according to claim 6, characterized in that: The measurement gap is determined based on a fourth control message; and The control message includes at least one of a Radio Resource Control (RRC) message, Downlink Control Information (DCI), and a Medium Access Control (MAC) Control Element (CE).

8. The method according to claim 6, characterized in that The method further includes receiving a terminal capability information message including terminal capability information from the terminal. The terminal capability information includes at least one of the following: an indicator indicating whether multiple measurement gaps with overlapping axes and of the same priority can be supported; or An indicator indicating that specific gap information among the plurality of measurement gaps can be applied according to an instruction from a base station.

9. The method according to claim 6, further comprising: receiving a fifth control message from the terminal, the fifth control message including a preference for a specific measurement gap among a plurality of measurement gaps having overlapping timelines and having the same priority; as well as sending a sixth control message to the terminal, the sixth control message including information about which measurement gap to apply based on the preference, wherein The specific measurement gap is determined based on a sixth control message.

10. A terminal in a wireless communication system, the terminal comprising: transceivers, which send and receive signals; as well as A control unit, wherein the control unit is configured to: receiving measurement configuration information from a base station, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; determining which of the plurality of measurement gaps to apply; determining whether to apply the determined measurement gap; and The measurement is performed by applying the gap. The terminal according to claim 10 , wherein: The control unit is configured to: receiving a first control message from a base station indicating application of a specific gap; and Based on the first control message, determining which measurement gap to apply, and wherein The control message is characterized by including at least one of a radio resource control (RRC) message, downlink control information (DCI), and a medium access control (MAC) control element (CE).

12. The terminal according to claim 10, wherein: The control unit is configured to: Sending a terminal capability information message including terminal capability information to a base station; sending a second control message to a base station, the second control message including a preference for a specific measurement gap among a plurality of measurement gaps having overlapping timelines and having the same priority; receiving a third control message from a base station, the third control message comprising information about which measurement gap to apply based on the preference; as well as Based on the third control message, determining which measurement gap to apply, or The control unit is characterized by controlling to determine to apply a measurement gap having a long gap application period (gap length or gap period) or to determine to sequentially apply a measurement gap, wherein The terminal capability information includes at least one of the following: an indicator indicating whether multiple measurement gaps with overlapping timelines and having the same priority can be supported; or An indicator indicating that specific gap information among the plurality of measurement gaps can be applied according to an instruction from a base station.

13. A base station in a wireless communication system, the base station comprising: transceivers, which send and receive signals; as well as A control unit, wherein the control unit is configured to: generating measurement configuration information to a terminal, the measurement configuration information including a plurality of measurement gaps having overlapping time axes and having the same priority; Sending measurement configuration information including the multiple measurement gaps to the terminal; as well as A fourth control message is sent indicating an application specific gap.

14. The base station according to claim 13, wherein: The specific measurement gap is determined based on a fourth control message, and the control message includes at least one of a radio resource control (RRC) message, downlink control information (DCI), and a medium access control (MAC) control element (CE).

15. The base station according to claim 13, characterized in that: The control unit receives a terminal capability information message including terminal capability information from the terminal; or The control unit receives a second control message from the terminal, the second control message including a preference for a specific measurement gap among a plurality of measurement gaps having overlapping time axes and having the same priority, and sends a third control message to the terminal, the third control message including information about which measurement gap is to be applied, wherein the specific measurement gap is determined based on the third control message, and The terminal capability information includes at least one of the following: An indicator indicating whether multiple measurement gaps with overlapping timelines and having the same priority can be supported; or An indicator indicating that specific gap information among the plurality of measurement gaps can be applied according to an instruction from a base station.

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