Method and apparatus for reporting delay status in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a terminal of a wireless communication system according to one embodiment of the present disclosure comprises the steps of: receiving, from a base station, configuration information indicating a remaining time threshold value for triggering a delay status report (DSR); triggering the DSR if the remaining time of a packet data convergence protocol (PDCP) discard timer of data buffered in a logical channel becomes smaller than the remaining time threshold value; and transmitting, to the base station, a medium access control-control element (MAC CE) for the DSR. The MAC CE includes a field indicating a value of the PDCP discard timer having the shortest remaining time for a logical channel group (LCG) of the logical channel at a time point of a first symbol for transmission of an initial physical uplink shared channel (PUSCH) including the MAC CE.

Description

Method and device for reporting delay status in a wireless communication system

[0001] The present disclosure relates to a wireless communication system. More specifically, the present disclosure relates to a method for reporting a delay status in a wireless communication system.

[0002] 5G 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 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] With the development of mobile communication systems as described above, the need for terminals to report various information to the base station has arisen in order for the base station to efficiently allocate uplink resources.

[0009] In one embodiment of the present disclosure, a method performed by a terminal of a wireless communication system is provided. The method comprises the steps of: receiving, from a base station, configuration information indicating a remaining time threshold for triggering a delay status report (DSR); triggering the DSR when a remaining time of a packet data convergence protocol (PDCP) discard timer of data buffered in a logical channel becomes smaller than the remaining time threshold; and transmitting, to the base station, a medium access control-control element (MAC CE) for the DSR. The MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for a logical channel group (LCG) of the logical channel at the time of a first symbol for an initial physical uplink shared channel (PUSCH) transmission including the MAC CE.

[0010] In one embodiment of the present disclosure, a method performed by a base station of a wireless communication system is provided. The method comprises the steps of: transmitting, to a terminal, configuration information indicating a remaining time threshold for triggering a DSR; and receiving, from the terminal, a MAC CE for the DSR when the remaining time of a PDCP discard timer of data buffered in a logical channel of the terminal becomes smaller than the remaining time threshold. The MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG of the logical channel at the time of a first symbol for initial PUSCH reception including the MAC CE.

[0011] In one embodiment of the present disclosure, a terminal of a wireless communication system is provided. The terminal includes a transceiver and a control unit. The control unit is configured to receive, from a base station through the transceiver, configuration information indicating a remaining time threshold for triggering a Disconnection Service Request (DSR), and, when the remaining time of a PDCP discard timer of data buffered in a logical channel becomes smaller than the remaining time threshold, trigger the DSR and transmit a MAC CE for the DSR to the base station through the transceiver. The MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG of the logical channel at the time of a first symbol for an initial PUSCH transmission including the MAC CE.

[0012] In one embodiment of the present disclosure, a base station of a wireless communication system is provided. The base station includes a transceiver and a control unit. The control unit is configured to transmit configuration information indicating a remaining time threshold for triggering a DSR to a terminal through the transceiver, and to receive a MAC CE for the DSR from the terminal through the transceiver when the remaining time of a PDCP discard timer of data buffered in a logical channel of the terminal becomes smaller than the remaining time threshold. The MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG of the logical channel at the time of a first symbol for initial PUSCH reception including the MAC CE.

[0013] According to an embodiment of the present invention, a base station can efficiently allocate uplink resources based on information transmitted from a terminal.

[0014] FIG. 1 is a diagram illustrating the structure of an NR system according to one embodiment of the present disclosure.

[0015] FIG. 2 is a diagram illustrating a wireless protocol structure in an NR system according to an embodiment of the present disclosure.

[0016] FIG. 3 is a diagram illustrating the remaining time of uplink data in a terminal's buffer and the amount of corresponding uplink data for each LCH according to one embodiment of the present disclosure.

[0017] FIG. 4 is a diagram illustrating a reference point of the remaining time according to one embodiment of the present disclosure.

[0018] FIG. 5 is a diagram illustrating an operation of discarding multiple PDUs of a PDU Set according to one embodiment of the present disclosure.

[0019] FIG. 6 is a diagram illustrating a procedure in which a base station and a terminal check whether a terminal supports DSR through RRC signaling and provide DSR-related settings according to one embodiment of the present disclosure.

[0020] FIG. 7 is a diagram illustrating the structure of a terminal according to one embodiment of the present invention.

[0021] FIG. 8 is a diagram illustrating the structure of a base station according to one embodiment of the present invention.

[0022] 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 throughout the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted.

[0023] In describing the embodiments of this disclosure, descriptions of technical details that are well known in the technical field to which this disclosure pertains and are not directly related to this disclosure will be omitted. This is to more clearly convey the gist of this disclosure without obscuring it by omitting unnecessary explanations.

[0024] 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.

[0025] 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 together 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 disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0026] 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, a 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 create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). 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).

[0027] 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 described 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.

[0028] Here, the term '~ part' used in the present embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ parts' may be combined into a smaller number of components and '~ parts' or further separated into additional components and '~ parts'. Additionally, components and '~parts' may be implemented to regenerate one or more CPUs within a device or secure multimedia card.

[0029] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of a Node B, a BS (Base Station), an eNB (eNode B), a gNB (gNode B), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a 5G UE, a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In addition, the embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type to the embodiments of the present disclosure described below. In addition, the embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure at the discretion of a person having skilled technical knowledge. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included here, and the 5G below may also be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems through some modifications within a scope that does not significantly deviate from the scope of the present disclosure, as judged by a person having skilled technical knowledge.

[0030] In the following description, terms used to identify connection nodes, terms referring to network entities or network functions (NFs), terms referring to messages, terms referring to interfaces between network objects, terms referring to various identification information, etc. 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 having equivalent technical meanings may be used.

[0031] For convenience of explanation below, some terms and names defined in the 3rd generation partnership project (3GPP) LTE (long term evolution) standard and / or 3GPP NR (new radio) standard may be used. However, the present disclosure is not limited to the above terms and names, and can be equally applied to systems conforming to other standards.

[0032] FIG. 1 is a diagram illustrating the structure of an NR system according to one embodiment of the present disclosure.

[0033] Referring to FIG. 1, the wireless communication system may be composed of multiple base stations (e.g., gNB (100), ng-eNB (110), ng-eNB (120), gNB (130)), an Access and Mobility Management Function (AMF) (140), and a User Plane Function (UPF) (150). Of course, the wireless communication system is not limited to the configuration illustrated in FIG. 1 and may include more or fewer components.

[0034] According to one embodiment of the present disclosure, a user equipment (hereinafter referred to as UE or terminal) (160) can access an external network through base stations (100, 110, 120, 130) and UPF (150).

[0035] In Fig. 1, base stations (100, 110, 120, 130) can serve as access nodes of a cellular network and provide wireless access to terminals accessing the network. For example, base stations (100, 110, 120, 130) can collect status information such as buffer status, available transmission power status, and channel status of terminals (160) to service user traffic, and perform scheduling based on the collected information to support connections between terminals and a core network (CN; in particular, the CN of NR is referred to as 5GC).

[0036] In Fig. 1, the gNB (100, 130) can control multiple cells and apply an adaptive modulation and coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel status of the terminal (160).

[0037] The core network is a device responsible for various control functions, including mobility management for terminals, and can be connected to multiple base stations (100, 110, 120, 130). 5GC can also be integrated with existing LTE systems.

[0038] Meanwhile, in a wireless communication system, a user plane (UP) related to transmission of actual user data and a control plane (CP) such as connection management may be configured separately. The gNB (100) and gNB (130) of FIG. 1 may use the UP and CP technologies defined in NR technology, and the ng-eNB (110) and ng-eNB (120), although connected to 5GC, may use the UP and CP technologies defined in LTE (Long Term Evolution) technology.

[0039] AMF (140) is a device that is responsible for various control functions as well as mobility management functions for terminals (160) and can be connected to multiple base stations (100, 110, 120, 130).

[0040] UPF (150) may refer to a type of gateway device that provides data transmission. Although not illustrated in FIG. 1, the NR wireless communication system may also include a Session Management Function (SMF). The SMF can manage packet data network connections, such as protocol data unit (PDU) sessions, provided to the terminal (160).

[0041] FIG. 2 is a diagram illustrating a wireless protocol structure in an NR system according to an embodiment of the present disclosure.

[0042] Referring to FIG. 2, the wireless protocol of the NR system may be composed of SDAP (Service Data Adaptation Protocol) (200) (290), PDCP (Packet Data Convergence Protocol) (210) (280), RLC (Radio Link Control) (220) (270), MAC (Medium Access Control) (230) (260), and PHY (Physical) (240) (250) in the terminal and the base station, respectively.

[0043] SDAP (Service Data Adaptation Protocol) (200) (290) can perform operations for transmitting user data, mapping QoS (Quality Of Service) flows to specific DRBs (Data Radio Bearers) for uplink and downlink, marking QoS flow IDs (Identifiers) for uplink and downlink, and mapping reflective QoS flows to data bearers for uplink SDAP PDUs. SDAP settings corresponding to each DRB can be provided from a higher RRC layer. Of course, the present invention is not limited to the above examples.

[0044] PDCP (Packet Data Convergence Protocol) (210) (280) can handle operations such as IP (Internet Protocol) header compression / decompression. Furthermore, PDCP (210) (280) can provide sequential and out-of-order transmission functions, reordering, duplicate detection, retransmission, encryption, and decryption functions. Of course, the above examples are not limited thereto.

[0045] Radio Link Control (220)(270) can reconfigure PDCP Protocol Data Unit (PDU) to an appropriate size. In addition, RLC (220)(270) can provide sequential and out-of-order transmission functions, and can provide Automatic Repeat Request (ARQ) functions, joining, segmentation, reassembly functions, re-segmentation functions, reordering functions, duplicate detection functions, and error detection functions. Of course, the present invention is not limited to the above examples.

[0046] MAC (230) (260) is connected to multiple RLC layer devices configured in one terminal, and can perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. In addition, MAC (230) (260) can provide a mapping function, a scheduling information reporting function, a HARQ (Hybrid ARQ) function, a priority control function between logical channels, a priority control function between terminals, an MBMS service confirmation function, a transmission format selection function, and a padding function. Of course, it is not limited to the above examples.

[0047] The physical (PHY) layer (240)(250) can perform an operation of channel coding and modulating upper layer data, converting it into an OFDM (Orthogonal Frequency Division Multiplexing) symbol and transmitting it through a wireless channel, or demodulating and channel decoding an OFDM symbol received through a wireless channel and transmitting it to a higher layer. In addition, the physical layer also uses HARQ (Hybrid ARQ) for additional error correction, and the receiving end can transmit whether or not a packet transmitted from the transmitting end has been received as 1 bit. The 1-bit information can be referred to as HARQ ACK (Acknowledgement) / NACK (Negative ACK) information.

[0048] Downlink HARQ ACK / NACK information for uplink data transmission can be transmitted through the PHICH (Physical Hybrid-ARQ Indicator Channel) physical channel in the case of LTE. Meanwhile, since NR applies asynchronous HARQ, whether retransmission is necessary or new transmission can be performed can be determined through the UE's scheduling information in the PDCCH (Physical Dedicated Control CHannel), which is a channel through which downlink / uplink resource allocation, etc. are transmitted. Uplink HARQ ACK / NACK information for downlink data transmission can be transmitted through the PUCCH (Physical Uplink Control Channel) or PUSCH (Physical Uplink Shared Channel) physical channel. PUCCH is generally transmitted in the uplink of the PCell (Primary Cell), but the base station can configure the SCell (Secondary Cell) to additionally transmit PUCCH to the UE if the UE supports it, and such SCell can be referred to as 'PUCCH SCell'.

[0049] Although not shown in Figure 2, an RRC (Radio Resource Control) layer may exist above the PDCP layer of each terminal and base station, and the RRC layer can transmit and receive connection and measurement-related setting control messages for radio resource control.

[0050] Meanwhile, the physical layer can be composed of one or more frequencies / carriers, and the technology that sets and uses multiple frequencies simultaneously is called carrier aggregation (CA). Using CA technology, instead of using only one carrier for communication between a terminal (or User Equipment, UE) and a base station (eNB or gNB), the transmission capacity can be increased by the number of subcarriers by additionally using the primary carrier and one or more subcarriers. Meanwhile, in LTE / NR, a cell within a base station that uses a primary carrier is called a PCell (Primary Cell), and a cell within a base station that uses a subcarrier is called an SCell (Secondary Cell).

[0051] In next-generation / 5G (New Radio, NR) wireless communication systems, terminals need to report their buffer status to the base station to help the base station more efficiently schedule resources. The Buffer Status Report (BSR) expresses the amount of uplink data stored in the terminal's buffer and can be used for reporting. According to the NR specification, the terminal can select an interval index that includes the amount of buffered uplink data to be reported from the range of uplink data amounts defined by index in the Buffer Size Table and include it in the BSR.

[0052] Buffer status reporting in an NR system can be performed based on MAC (Medium Access Control) layer signaling between a terminal and a base station. For example, when a BSR is triggered at a specific transmission time, the terminal can include a BSR MAC CE control element (MAC CE) in a MAC PDU and transmit it to the base station. At this time, the BSR MAC CE can indicate the amount of packets remaining in the transmission buffer of the terminal after the corresponding MAC PDU is configured, in units of Logical Channel Groups (LCGs). The base station can estimate the amount of uplink data currently remaining in the buffer of the terminal using the received BSR. In an NR system, the terminal can manage the uplink data transmission buffer to be transmitted to the base station for each LCG for multiple LCGs (e.g., 8 LCGs).

[0053] Meanwhile, in NR systems, certain types of uplink data (e.g., Extended Reality (XR) uplink data) may have a delay budget, such as the remaining time remaining. To be considered valid, uplink data must arrive at the uplink server within a predetermined remaining time, based on a time generated by the terminal's application layer. If the data fails to arrive at the uplink server within the predetermined remaining time, it may lose its application value.

[0054] As previously explained, the terminal buffer size reported by BSR can indicate the total amount of uplink data stored in the terminal's buffer. However, the base station may not know how much of the total uplink data is close to its deadline, i.e., how little time is remaining.

[0055] If the base station knows the remaining time of uplink data in the terminal buffer and the corresponding amount of uplink data for each remaining time, it can allocate uplink resources based on this information to prioritize transmission of data with a relatively short remaining time. Consequently, more uplink data can be transmitted before the remaining time expires, improving cell capacity.

[0056] On the other hand, if the remaining time of specific uplink data is very short, the time between the time reported to the BSR and the time of actual transmission may exceed the remaining time. In such cases, the data may be transmitted after it has already lost its application value or may be discarded before transmission. Consequently, the allocated uplink resources may not be used to transmit valid data, resulting in resource waste. Therefore, the present disclosure proposes methods for including the remaining time, or the remaining time and amount of data, that satisfy a predefined remaining time criterion (upper or lower limit) in the information reported by a terminal to a base station, thereby enabling the base station to utilize this information to more efficiently allocate uplink resources to terminals.

[0057] According to one embodiment of the present disclosure, a method is provided for reporting to a base station the remaining time of uplink data stored in a transmission buffer of a terminal and / or the amount of data corresponding to the remaining time, and utilizing the information for uplink scheduling of the base station.

[0058] A terminal may trigger a BSR (Buffer Status Report) in the corresponding Cell Group if at least one or a combination of the following conditions is satisfied.

[0059] - Condition 1-1: When new uplink data is generated on a Logical Channel (LCH) belonging to a Logical Channel Group (LCG), and the priority of the LCH is higher than the priorities of other LCHs that have uplink data. In this case, the terminal can consider the triggered Regular BSR to have been triggered by the LCH where new uplink data is generated.

[0060] - Condition 1-2: When new uplink data is generated on a Logical Channel (LCH) belonging to a Logical Channel Group (LCG), and uplink data does not exist on any LCH belonging to any LCG before the generation of the uplink data. In this case, the terminal can assume that the triggered Regular BSR was triggered by the LCH where the new uplink data was generated.

[0061] - Condition 1-3: When the configured timer (e.g., retxBSR-Timer) expires, if there is uplink data in at least one LCH and the LCH belongs to an LCG, the terminal can consider that the triggered Regular BSR was triggered by the LCH with the highest priority among the LCHs that have uplink data.

[0062] In one embodiment of the present disclosure, when a specific timer (e.g., logicalChannelSR-DelayTimer) for an LCH that triggered the Regular BSR is not running while a Regular BSR has already been triggered, the terminal may trigger an SR (Scheduling Request) corresponding to the LCH for the Regular BSR if at least one or a combination of the following conditions is satisfied.

[0063] - Condition 2-1: When there are no UL-SCH (Uplink Shared Channel) resources for initial transmission (or new transmission)

[0064] - Condition 2-2: If the MAC Entity has configured grant(s) and the LCH that triggered the Regular BSR has logicalChannelSR-Mask set to false,

[0065] - Condition 2-3: If there are UL-SCH resources for initial transmission, but due to LCP (Logical Channel Prioritization) mapping restrictions, the UL-SCH resources cannot be used for the LCH that triggered the Regular BSR.

[0066] Here, the logicalChannelSR-Mask may be a parameter that controls SR triggering when a configured grant is set.

[0067] In one embodiment of the present disclosure, a terminal may report the remaining time status of uplink data in a transmission buffer to a base station via a specific MAC CE. For example, the MAC CE may be referred to as a Delay Status Report (DSR) MAC CE.

[0068] According to one embodiment of the present disclosure, in relation to DSR, a base station may set at least one or a combination of the following information elements or parameters for a specific MAC Entity (or Cell Group) of a terminal via an RRC message.

[0069] - Whether or not to report the remaining time can be set for each LCH / LCG. According to one embodiment, an LCH / LCG that reports the remaining time may be referred to as a dsr-lch / dsr-lcg. For example, if a specific LCG is set as a dsr-lcg, all LCHs belonging to the LCG may be regarded as dsr-lch. For example, an LCG that includes one or more dsr-lchs may be regarded as a dsr-lcg. For example, an LCG / LCH for which a DSR reporting remaining time criterion or a DSR trigger remaining time criterion described below is set may be regarded as a dsr-lcg / dsr-lch.

[0070] - A DSR reporting remaining time criterion may be set. The criterion may be a remaining time upper limit, a lower limit, or both an upper limit and a lower limit. For example, if a remaining time upper limit is set, the terminal may report the remaining time and / or buffer size for uplink data whose remaining time is less than or equal to the set remaining time upper limit. For example, if a remaining time lower limit is set, the terminal may report the remaining time and / or buffer size for uplink data whose remaining time is greater than or equal to the set remaining time lower limit. For example, if a remaining time upper limit and a remaining time lower limit are set, the terminal may report the remaining time and / or buffer size for uplink data whose remaining time is greater than or equal to the lower limit and less than or equal to the upper limit. For example, one or more of the above remaining time criteria may be set per LCH, per LCG, per MAC Entity, or per terminal. For example, if the DSR report remaining time criterion is not set, the terminal may regard the DSR trigger remaining time criterion described below as the DSR report remaining time criterion. For example, if multiple DSR report remaining time criteria or DSR trigger remaining time criteria are set, the terminal may trigger DSR for each DSR trigger remaining time criterion and / or the terminal may report the remaining time and / or buffer size to the base station through DSR for uplink data having a remaining time that satisfies the corresponding criteria for each DSR report remaining time criterion or DSR trigger remaining time criterion.

[0071] - An upper limit on the number of remaining time fields may be set. For example, an upper limit on the number of pairs of remaining time fields and remaining time-specific buffer size fields may be set. The upper limit on the number of remaining time fields may be set for each LCH, each LCG, or the entire DSR MAC CE. When the upper limit on the number of remaining time fields is set, the terminal may include in the DSR a number of remaining time fields or pairs of remaining time fields and remaining time-specific buffer size fields that is less than or equal to the upper limit set by the base station, for each LCH, each LCG, or the entire DSR.

[0072] - A DSR trigger remaining time criterion may be set. For example, the DSR trigger remaining time criterion may be a remaining time upper limit, a lower limit, or both. The DSR trigger remaining time criterion may be set for each LCH, each LCG, each MAC entity, or each terminal. For example, if the DSR trigger remaining time criterion is not separately set, the terminal may directly apply the DSR reporting remaining time criterion set for each LCH / LCG / MAC entity / Cell Group / terminal as the DSR trigger remaining time criterion, or may be determined by introducing a specific offset into the DSR reporting remaining time criterion. The offset may be determined in advance, or may be set by the base station through RRC. For example, there may be one or more DSR trigger remaining time criteria for each LCG.

[0073] According to one embodiment of the present disclosure, remaining time-related values / fields / variables / parameters may be expressed in the form of integers having a specific time unit. The integers may express absolute time or relative time relative to a specific point in time. For example, the time unit may have one or more composite forms of units such as microseconds, milliseconds, seconds, symbols, slots, subframes, and frames.

[0074] According to one embodiment, a residual time table may be predefined, and each index / codepoint included in the residual time table may be specified to indicate a specific residual time interval. The predefined residual time table may refer to a table that the terminal and the base station have pre-stored according to the standard. According to one embodiment, a plurality of residual time tables may be predefined, and the base station may indicate one residual time table to be actually applied among them through RRC, MAC CE, or DCI (downlink control information).

[0075] Different indexes / codepoints of the above remaining time table may indicate different non-overlapping remaining time intervals. The maximum remaining time included in the above remaining time table may be equal to the maximum value of the discardTimer set in the PDCP-Config of the 38.331 specification, or may be a value obtained by applying a specific offset to the maximum value. A specific index / codepoint (e.g., the last index / codepoint) of the above remaining time table may indicate all time intervals greater than or equal to the maximum remaining time. For example, 2 in the above remaining time table k dog or 2 k Less than or equal to a dog but 2 k-1When containing a number of indices / codepoints greater than k, the remaining time field or minimum remaining time field of the DSR may have a length of k-bits.

[0076] According to one embodiment of the present disclosure, a remaining time-related value / field / variable / parameter may be expressed as a specific index / codepoint of the remaining time table. For example, when the value indicated by the remaining time field of the DSR or the upper or lower limit of the remaining time set by the base station is t, this may mean the index / codepoint t of the remaining time table.

[0077] FIG. 3 is a diagram illustrating the remaining time of uplink data in a terminal's buffer and the amount of corresponding uplink data for each LCH according to one embodiment of the present disclosure.

[0078] According to one embodiment, the terminal may report the remaining time status of uplink data in the corresponding LCG buffer for each LCG (dsr-lcg) through DSR.

[0079] In one embodiment of the present disclosure, the minimum division interval of remaining time reported through DSR may be an interval indicated by each index / codepoint of the remaining time table when the remaining time field indicates an index / codepoint, and may be the time unit when an integer having a specific time unit is indicated.

[0080] In one embodiment, the remaining time or the buffer size per remaining time or the Delay-Critical buffer size reported via DSR may be reported only for the uplink data remaining in a specific LCH / LCG / MAC Entity / Cell Group buffer, excluding the uplink data included in the MAC PDU after the MAC PDU including the DSR MAC CE is constructed.

[0081] A DSR MAC CE may contain one or more of the following information elements or fields:

[0082] - LCH or LCG indicator

[0083] ■ The LCG / LCH ID field or a specific position bit of the Bitmap can be used to indicate the corresponding LCG / LCH. For example, the LCG / LCH indicator can be used to indicate the presence or absence of a remaining time field corresponding to the corresponding DSR MAC CE, or a minimum remaining time field, or a pair of a (minimum) remaining time field and a buffer size field for each remaining time, or a Delay-Critical buffer size field.

[0084] - Remaining time field

[0085] ■ If the base station sets only the remaining time criterion for each LCH, LCG, or MAC Entity / Cell Group and does not set an upper limit on the number of remaining time fields:

[0086] ◆ The terminal can indicate only the remaining time of uplink data that satisfies the remaining time criterion among the uplink data in the corresponding (one or more) LCH (dsr-lch) buffer for each LCH, each LCG, or the entire MAC Entity / Cell Group. At this time, the terminal can add the corresponding remaining time field when there is uplink data corresponding to the buffer for each remaining time minimum division section. Referring to Fig. 3, as an example, if the base station sets the remaining time upper limit to 4 for both LCH 1 and LCH 2, and the terminal wants to report the remaining time for each LCG, there can be two remaining time fields corresponding to LCG 0 (including LCH 1 and LCH 2), and the terminal can indicate the remaining time 3 (BS of LCH 1) 1-3 and BS of LCH 2 2-3 ) and remaining time 4 (BS of LCH 2 2-4Each can be directed to (reflecting).

[0087] ■ If the base station sets both the remaining time criterion and the upper limit of the number of remaining time fields for each LCH, LCG, or MAC Entity / Cell Group:

[0088] ◆ The terminal can indicate only the remaining time of uplink data that satisfies the remaining time criterion among the uplink data in the corresponding (one or more) LCH (dsr-lch) buffer for each LCH, each LCG, or the entire MAC Entity / Cell Group. At this time, the terminal can add the corresponding remaining time field when there is uplink data corresponding to the buffer for each remaining time minimum division section. For example, the number of remaining time fields per LCH, per LCG, or per MAC Entity / Cell Group added by the terminal may exist up to the upper limit of the number of remaining time fields set per LCH, per LCG, or per MAC Entity / Cell Group set by the base station (or the upper limit of the number of remaining time fields - 1). For example, the terminal can add remaining time fields in ascending order from the remaining time field with the shortest remaining time. Referring to FIG. 3, for example, if the base station sets the upper limit of the remaining time for both LCH 1 and LCH 2 to 4 and sets the upper limit of the number of remaining time fields of LCG 0 to 1, there can be only one remaining time field corresponding to LCG 0, and the terminal can set the remaining time 3 (BS of LCH 1) 1-3 and BS of LCH 2 2-3 ) can be directed to.

[0089] ■ If the base station does not set the remaining time criteria for each LCH, LCG, or MAC Entity / Cell Group as a whole, but only sets the upper limit of the number of remaining time fields:

[0090] ◆ The terminal can indicate the remaining time of uplink data in the corresponding (one or more) LCH (dsr-lch) buffer for each LCH, each LCG, or the entire MAC Entity / Cell Group. At this time, the terminal can add the corresponding remaining time field for each minimum segmentation section, if there is corresponding uplink data. For example, the number of remaining time fields per LCH, per LCG, or per MAC Entity / Cell Group added by the terminal may exist up to the upper limit of the number of remaining time fields set per LCH, per LCG, or per MAC Entity / Cell Group set by the base station (or the upper limit of the number of remaining time fields - 1). For example, the terminal can add remaining time fields in ascending order from the remaining time field with the shortest remaining time. Referring to FIG. 3, for example, if the base station sets the upper limit of the number of remaining time fields of LCG 0 to 1 and reports the remaining time for each LCG, there may be one remaining time field corresponding to LCG 0, and the terminal may set the remaining time 3 (BS of LCH 1) 1-3 and BS of LCH 2 2-3 ) can be directed to.

[0091] - Minimum remaining time field: The terminal can indicate the remaining time interval to which the remaining time of the uplink data with the shortest remaining time belongs among the uplink data in the corresponding (one or more) LCH (dsr-lch) buffers for each LCH, each LCG, or the entire MAC Entity / Cell Group. At this time, the terminal can indicate the corresponding remaining time interval by adding a remaining time field. The remaining time field may be referred to as a minimum remaining time field. For example, the minimum remaining time field may be added only when the corresponding remaining time interval satisfies the remaining time criteria set by the base station when the base station sets the remaining time criterion. Referring to FIG. 3, as an example, when the base station sets the upper limit of the remaining time of LCG 0 to 4 and reports the remaining time for each LCG, LCG 0 can have one minimum remaining time field, and the field can indicate a remaining time of 3.

[0092] - (Minimum) remaining time-specific buffer size field: If there is one or more remaining time fields corresponding to a specific LCH / LCG / MAC Entity / Cell Group, and / or if there is a minimum remaining time field corresponding to a specific LCH / LCG / MAC Entity / Cell Group, a (minimum) remaining time-specific buffer size field may be included, which indicates the amount of uplink data having a remaining time belonging to the remaining time interval indicated by the corresponding field in the corresponding LCH / LCG / MAC Entity / Cell Group buffer for each remaining time or minimum remaining time field. Referring to FIG. 3, for example, if the upper limit of the remaining time set by the base station for LCG 0 is 4 and the terminal performs remaining time reporting for each LCG, LCG 0 may have two remaining time fields, and the fields may indicate remaining times 3 and 4, respectively. For example, one buffer size field for each remaining time corresponding to the remaining time field indicating the remaining time 3 may be added. In this case, the field is BS, which is the buffer size corresponding to the remaining time 3. 1-3 +BS 2-3 can be indicated. For example, one remaining time field corresponding to the remaining time field indicating the remaining time 4 may be added. In this case, the field may be BS, which is the buffer size corresponding to the remaining time 4. 2-4 can be directed.

[0093] - Delay-Critical Buffer Size Field: If the base station sets the remaining time criterion for each LCH / LCG / MAC Entity / Cell Group, the Delay-Critical buffer size field may be included, which indicates the amount of uplink data having a remaining time that satisfies the remaining time criterion set by the base station among the uplink data in the corresponding (one or more) LCH (dsr-lch) buffer. The number of the Delay-Critical buffer size fields may exist for each LCH / LCG / MAC Entity / Cell Group and for each remaining time criterion set by the base station. For example, if the base station sets criterion 1 having an upper limit of 1 for the remaining time and criterion 2 having an upper limit 2 and a lower limit 2 for a specific LCH / LCG / MAC Entity / Cell Group, there may be two Delay-Critical buffer size fields corresponding to the corresponding LCH / LCG / MAC Entity / Cell Group. For example, the first Delay-Critical Buffer Size field may indicate the amount of uplink data (uplink buffer size) that has remaining time that satisfies criterion 1, and the second Delay-Critical Buffer Size field may indicate the amount of uplink data (uplink buffer size) that has remaining time that satisfies criterion 2. For example, the base station may set the remaining time criteria(s) in the form of a List formed by multiple integers. In this case, when the integers are arranged in ascending order, two adjacent values ​​may be regarded as one remaining time criteria and may be regarded as the lower limit and the upper limit of the corresponding remaining time criteria. In addition, the smallest value may be regarded as the upper limit of a specific remaining time criteria, and the corresponding remaining time criteria may be a remaining time criteria having only an upper limit.For example, if a base station sets a list indicating remaining time criteria as [x1, x2, x3] (e.g., x1 < x2 < x3), the terminal can interpret that the base station has set three remaining time criteria, and can interpret them as 1) a remaining time criterion with an upper limit of x1, 2) a remaining time criterion with a lower limit of x1 and an upper limit of x2, and 3) a remaining time criterion with a lower limit of x2 and an upper limit of x3.

[0094] In the present disclosure, the remaining time criterion may mean a DSR report remaining time criterion or a DSR trigger remaining time criterion set by the base station through RRC.

[0095] For example, the above (minimum) remaining time-based buffer size field or Delay-Critical buffer size field may refer to a buffer size table in which an index for each buffer size section is defined in advance, and indicate the index of the corresponding buffer size section in the table. The buffer size table may be one of the Long BS (Buffer Size) Table for the 8-bit Buffer Size field defined in the NR system, the Short BS table for the 5-bit Buffer Size field, or one or more New BS Tables that may be newly defined in the future. In case there are multiple applicable candidate BS Tables, a BS Table indicator indicating which BS Table the (minimum) remaining time-based buffer size field or Delay-Critical buffer size field refers to may be included in the DSR MAC CE reported by the terminal for each (minimum) remaining time-based buffer size field or Delay-Critical buffer size field, or for each LCH, or for each LCG, or for each MAC Entity / Cell Group. For example, there may be multiple candidate BS Tables that a terminal can refer to for a specific LCH / LCG. In this case, if the buffer size indicated by the (minimum) remaining time-based buffer size field or the Delay-Critical buffer size field of the corresponding LCH / LCG falls within a buffer interval defined in multiple candidate BS Tables, the terminal may select, from among the multiple candidate BS Tables, a candidate BS Table having a smallest buffer interval size (difference between the upper and lower limits) to which the buffer size belongs, or a candidate BS Table having a specific partial buffer size interval defined instead of the entire buffer size interval being '0 to Infinity'. The terminal may report the buffer size to the base station by referring to one of the selected BS Tables.

[0096] FIG. 4 is a diagram illustrating a reference point of the remaining time according to one embodiment of the present disclosure.

[0097] Referring to FIG. 4, according to one embodiment of the present disclosure, a reference time of the remaining time indicated by the remaining time field or the minimum remaining time field of the DSR MAC CE or applied to the Delay-Critical buffer size field is illustrated.

[0098] According to one embodiment, the reference point of the remaining time may indicate a point in time from which the remaining time is based.

[0099] Typically, a terminal can transmit a MAC PDU or a TB (Transport Block) containing a DSR MAC CE to the base station via PUSCH resources allocated by the base station. According to one embodiment, the base station can allocate specific PUSCH resources to the terminal via DCI through dynamic scheduling. Alternatively, multiple periodic PUSCH resources may be allocated to the terminal in a CG (Configured Grant) format.

[0100] The remaining time reference point indicated by the Remaining Time field or Minimum Remaining Time field of the DSR MAC CE, or applied by the Delay-Critical Buffer Size field, may be at least one or a combination of the following options:

[0101] - The first symbol of the PUSCH resource for the initial transmission of the MAC PDU or TB including the DSR MAC CE or the starting point of the first symbol (400)

[0102] - The last symbol of the PUSCH resource for the initial transmission of the MAC PDU or TB including the DSR MAC CE or the end point of the last symbol (410)

[0103] - The starting point (420) of the slot to which the PUSCH resource belongs for the initial transmission of the MAC PDU or TB including the DSR MAC CE, or the first slot to which the PUSCH resource belongs when the PUSCH resource spans multiple slots is scheduled.

[0104] - The end point (430) of the slot to which the PUSCH resource belongs for the initial transmission of the MAC PDU or TB including the DSR MAC CE, or the last slot to which the PUSCH resource belongs when the PUSCH resource spans multiple slots is scheduled.

[0105] According to one embodiment, the PUSCH resource may be a resource allocated by the base station as a Dynamic Grant through Dynamic Scheduling or a resource allocated by the base station as a Configured Grant.

[0106] According to one embodiment, one or more reference time points indicating the remaining time reference time points may be added to the DSR. For example, the reference time point field may indicate a reference time point applied when calculating the remaining time value indicated by the remaining time field of the DSR or the uplink data indicated by the Delay-Critical buffer size field. For example, the reference time point field may indicate an absolute time or a relative time with respect to a specific time point. For example, the reference time point field may be expressed as one or a combination of units such as Frame, Subframe, Slot, Symbol, or an absolute time value such as microsecond, millisecond, or second. For example, the reference time point field may indicate all or a specific position / number of bits or a specific position / number of LSBs (Least Significant Bits) or a specific position / number of MSBs (Most Significant Bits) of UTC (universal time coordinated) time.

[0107] According to one embodiment, the remaining time field of the DSR may be a field indicating a relative difference compared to a specific remaining time upper limit set by the base station, rather than an absolute remaining time. For example, the relative difference may be a value obtained by subtracting the remaining time from the remaining time upper limit, or may be a value indicating how many times smaller / larger or how much the remaining time is compared to the remaining time upper limit. For example, when the DSR includes multiple remaining time fields for each LCH / LCG, the first remaining time field may indicate the absolute remaining time for the LCH / LCG, and from the remaining time fields included thereafter, may indicate the relative time difference compared to the remaining time indicated by the immediately preceding remaining time field(s).

[0108] According to one embodiment, the remaining time of uplink data in the LCH (dsr-lch) buffer at a specific point in time may be equal to the remaining time value of the PDCP discardTimer of the uplink data as of that point in time, or may be equal to a value obtained by applying a specific offset to the PDCP discardTimer remaining time value. The offset may be defined in advance or may be set by the base station via RRC.

[0109] According to one embodiment, the remaining time of a specific PDU included in a specific PDU set at a specific point in time may be regarded as / set / reset as the remaining time of the PDU with the smallest remaining time among all PDUs included in the PDU set as of that point in time, or the PDU generated first in the Application, or the PDU that arrived first at the PDCP.

[0110] According to one embodiment, the remaining time of a specific PDU included in a specific PDU set at a specific point in time may be regarded as / set / reset as the remaining time of the PDU with the smallest remaining time among all PDUs included in the PDU set as of that point in time, the PDU generated first in the Application, or the PDU that arrived first in the PDCP, if PSIHI (PDU-Set Integrated Handling Information) is set for the QoS Flow to which the PDU set belongs.

[0111] According to one embodiment, the remaining time of a specific PDU included in a specific PDU set at a specific point in time may be regarded as / set / reset to the remaining time of the PDU set level PDCP discardTimer of the PDU set at that point in time, or to a value obtained by applying a specific offset set by the base station to the remaining time, if a PDU set level PDCP discardTimer is set for the PDU set. The offset may be defined in advance or may be set by the base station via RRC.

[0112] According to one embodiment, the remaining time for all PDUs included in a specific PDU set at a specific point in time may be calculated as the remaining PDU Set Delay Budget (PSDB) or the remaining AN (Access Network) PSDB of the PDU set at that point in time, or as a value obtained by applying a specific offset to the remaining time value. The offset may be defined in advance or may be set by the base station via RRC.

[0113] For example, the PSDB of a specific QoF Flow can be defined as follows.

[0114] - The PDU Set Delay Budget (PSDB) defines an upper bound for the delay that a PDU Set may experience for the transfer between the UE and the N6 termination point at the UPF, ie the duration between the reception time of the first PDU (at the N6 termination point for DL ​​or the UE for UL) and the time when all PDUs of a PDU Set have been successfully received (at the UE for DL ​​or N6 termination point for UL).

[0115] In one embodiment of the present disclosure, the AN PSDB of a specific QoS Flow may be calculated as the PSDB of the QoS Flow minus the CN (Core Network) PDB of the QoS Flow.

[0116] According to one embodiment, the DSR MAC CE trigger condition may be at least one of the following conditions:

[0117] - Condition 2-1: If uplink data that satisfies the DSR trigger remaining time criterion is generated in a specific LCG (dsr-lcg) / LCH (dsr-lch), and there is no uplink data that satisfies the criterion in the MAC Entity or Cell Group or LCG to which the LCG (dsr-lcg) / LCH (dsr-lch) belongs, the DSR MAC CE may be triggered. For example, the generation of uplink data that satisfies the DSR trigger remaining time criterion may mean that new uplink data that satisfies the criterion is generated, or that the criterion is satisfied as the remaining time of uplink data that was previously in the buffer is reduced. For example, a DSR triggered by the above condition 2-1 may be referred to as Regular DSR.

[0118] - Condition 2-2: If uplink data that satisfies the DSR trigger remaining time criterion is generated in a specific LCG (dsr-lcg) / LCH (dsr-lch), and the LCH / LCG priority level of the uplink data is higher than the LCH / LCG priority level of other uplink data that satisfies the criteria of the MAC Entity or Cell Group to which the LCG (dsr-lcg) / LCH (dsr-lch) belongs or the LCG, the DSR MAC CE may be triggered. For example, uplink data that satisfies the DSR trigger remaining time criterion may be generated because new uplink data that satisfies the criteria is generated, or because the remaining time of existing uplink data is reduced and satisfies the criteria. For example, a DSR triggered by the above condition 2-2 may be referred to as Regular DSR.

[0119] - Condition 2-3: When uplink data that satisfies the DSR trigger remaining time criterion is generated in a specific LCG (dsr-lcg) / LCH (dsr-lch), and the remaining time of the uplink data is less than the remaining time of other uplink data that satisfies the criteria of the MAC Entity or Cell Group to which the LCG (dsr-lcg) / LCH (dsr-lch) belongs or the LCG, the DSR MAC CE may be triggered. For example, the generation of uplink data that satisfies the DSR trigger remaining time criterion may mean that new uplink data that satisfies the criteria has been generated, or that the remaining time of existing uplink data has been reduced to satisfy the criteria. For example, a DSR triggered by the above condition 2-3 may be referred to as Regular DSR.

[0120] - Condition 2-4: The base station may set a DSR retransmission timer (e.g., retxDSR-Timer) for the terminal. When the DSR retransmission timer expires, if there is uplink data satisfying the DSR trigger remaining time criterion in at least one LCG (dsr-lcg) / LCH (dsr-lch), the DSR MAC CE may be triggered. For example, the DSR retransmission timer may be a different timer from the BSR retransmission timer (e.g., retxBSR-Timer). For example, the DSR retransmission timer may be the same timer as the BSR retransmission timer. For example, the size of the DSR retransmission timer may be set by the base station via RRC for each MAC Entity / Cell Group / LCG. For example, a DSR triggered due to the expiration of a DSR retransmission timer may be regarded as triggered in an LCG (dsr-lcg) / LCH (dsr-lch) with the highest priority among the LCGs (dsr-lcg) / LCHs (dsr-lch) that have uplink data satisfying the DSR trigger remaining time criterion at the time the timer expires. After the UE performs Logical Channel Prioritization (LCP) on available UL-SCH resources, if the UL-SCH resources include a DSR MAC CE and the corresponding subheader, the UE may start / restart the DSR retransmission timer. For example, a DSR triggered due to the expiration of the DSR retransmission timer may be referred to as Regular DSR.

[0121] - Condition 2-5: The base station may set a periodic DSR timer (e.g., periodicDSR-Timer) for the terminal. When the periodic DSR timer expires, a DSR MAC CE may be triggered. For example, the periodic DSR timer may be a different timer from a periodic BSR timer (periodicBSR-Timer). For example, the periodic DSR timer may be the same timer as the periodic BSR timer. For example, after the terminal performs LCP (Logical Channel Prioritization) for available UL-SCH resources, if the UL-SCH resources include a DSR MAC CE and a corresponding subheader that is not a truncated DSR, the terminal may start / restart the periodic DSR timer. For example, the size of the periodic DSR timer may be set by the base station through RRC for each MAC Entity / Cell Group / LCG. For example, if the base station sets the size of the periodic DSR timer to 'infinity', the timer may not expire, and thus a DSR trigger due to expiration of the periodic DSR timer may not occur.

[0122] - Condition 2-6: When a padding bit occurs as an LCP result for a specific UL-SCH, if there is uplink data that satisfies the DSR trigger remaining time criterion in at least one LCG (dsr-lcg) / LCH (dsr-lch), the UE can trigger a padding DSR transmitted instead of the padding bit. For example, a truncated DSR may mean a DSR MAC CE that transmits only a portion of the DSR fields when the padding bits are not enough to accommodate the entire DSR field in a padding DSR transmitted using padding bits.

[0123] - Condition 2-7: If the remaining time of the uplink data with the shortest remaining time among the uplink data of a specific LCG (dsr-lcg) satisfies the DSR trigger remaining time criterion corresponding to the LCG (dsr-lcg) set by the base station, DSR may be triggered. For example, the DSR trigger remaining time criterion may be a remaining time upper limit, or a remaining time lower limit, or may include a remaining time lower limit and a remaining time upper limit. For example, satisfying the remaining time criterion may mean that the remaining time of the uplink data is less than or less than or equal to the set remaining time upper limit. For example, satisfying the remaining time criterion may mean that the remaining time of the uplink data is greater than or greater than or equal to the set remaining time lower limit. For example, meeting the remaining time criterion may mean that the remaining time of the uplink data is less than or equal to a set remaining time upper limit, and greater than or equal to a set remaining time lower limit.

[0124] - Condition 2-8: When there is uplink data among the uplink data of a specific LCG (dsr-lcg) whose remaining time satisfies the DSR trigger remaining time criterion corresponding to the LCG (dsr-lcg), DSR can be triggered. The DSR trigger remaining time criterion can be the same as that described in the above-mentioned condition 2-7.

[0125] For example, among the above conditions 2-1 to 2-8, the presence / occurrence of uplink data that meets the DSR trigger remaining time criteria in a specific LCG (dsr-lcg) / LCH (dsr-lch) may mean at least one of the following options or a combination thereof.

[0126] - Option 1: For the LCG / LCH in question, if there is a PDU in the PDCP / RLC buffer that does not belong to the PDU Set and the remaining time meets the DSR trigger remaining time criteria.

[0127] - Option 2: When the remaining time of the first / earliest arrived PDU of a specific PDU Set of the corresponding LCG / LCH satisfies the corresponding DSR trigger remaining time criterion, and at least one PDU / PDU segment belonging to the corresponding PDU Set exists in the PDCP / RLC buffer. For example, Option 2 may also include a case where one or more PDUs among the above PDU Set have not yet arrived at the corresponding PDCP Entity of the terminal. For example, Option 2 may be valid only when PSIHI is set for the QoS Flow of the corresponding PDU Set or when pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0128] - Option 3: When the remaining time of the first / earliest arrived PDU of a specific PDU Set of the LCG / LCH satisfies the DSR trigger remaining time criterion, and the PDU Set contains one or more PDUs / PDU Segments that have not yet arrived at the PDCP layer from an upper layer or are present in the PDCP / RLC buffer. For example, Option 3 may also include a case where there are no PDUs / PDU Segments belonging to the PDU Set in the PDCP / RLC buffer, but there are PDUs / PDU Segments that have not yet arrived at the PDCP layer from an upper layer. For example, Option 3 may be valid only when PSIHI is set for the QoS Flow of the PDU Set or when pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow of the PDU Set.

[0129] - Option 4: When the remaining time of the first / earliest arrived PDU of a specific PDU Set of the corresponding LCG / LCH satisfies the corresponding DSR trigger remaining time criterion, all PDUs belonging to the PDU Set have already arrived at the PDCP layer from the upper layer, and one or more PDUs / PDU Segments exist in the PDCP / RLC buffer. For example, Option 4 may be valid only when PSIHI is set for the corresponding PDU Set / LCH / QoS Flow. For example, Option 4 may be valid only when pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0130] - Option 5: The base station can set the validity of at least one option among Option 1 to Option 4 through an RRC message.

[0131] For example, to prevent DSR from being over-triggered, the terminal may apply at least one of the following options:

[0132] - The terminal may not trigger DSR again for uplink data of an LCG / LCH / MAC entity that triggered a pending DSR that has not yet been canceled. For example, if the DSR trigger remaining time criterion of the LCG / LCH / MAC entity to which the uplink data to trigger a new DSR belongs includes a remaining time upper limit, and the remaining time upper limit is smaller than the remaining time upper limit of another LCG / LCH / MAC entity that has already triggered a DSR, the terminal may trigger a DSR for the corresponding uplink data. For example, the SR Configuration for DSR may be set for each LCG / LCH, and when a DSR is triggered by a specific LCG / LCH, the SR of the corresponding LCG / LCH may be triggered.

[0133] - For example, if a DSR that has not yet been canceled is triggered for another PDU belonging to the same PDU Set, an additional DSR may not be triggered for that PDU.

[0134] - Even if there are multiple pending DSRs that have not yet been canceled, one MAC PDU can contain at most one DSR MAC CE.

[0135] FIG. 5 is a diagram illustrating an operation of discarding multiple PDUs of a PDU Set according to one embodiment of the present disclosure.

[0136] According to one embodiment of the present disclosure, a PDU Set may include multiple PDUs, and the multiple PDUs may arrive at the PDCP layer of a terminal at different times.

[0137] At this time, referring to FIG. 5, a specific PDU Set (570) may include multiple PDUs (571, 572, 573). The times at which the multiple PDUs (571, 572, 573) arrive at the PDCP layer from the upper layer of the terminal may be different (500, 520, 530). For example, multiple PDUs of a specific PDU Set may each arrive at the PDCP layer in the form of a PDCP SDU. For example, when a new PDCP SDU is generated, the PDCP Entity may start a dedicated discardTimer for the PDCP SDU. For example, the time from the start of the discardTimer of a specific PDCP SDU to its expiration may be determined by the discardTimer setting value of the DRB / QoS Flow to which the PDCP SDU belongs, according to the PDCP setting value for each DRB / QoS Flow. Therefore, multiple PDCP SDUs, each containing multiple PDUs of a specific PDU Set, may have the same discardTimer setting value. If multiple PDUs (561, 562, 563) of a specific PDU Set arrive at the PDCP Entity at different times, the times at which the corresponding discardTimer expires may be different even if the multiple PDCP SDUs have the same discardTimer setting value.

[0138] For example, the base station can configure the terminal to perform a PDCP SDU discard operation due to expiration of the PDCP discardTimer on a per-PDU set basis via an RRC message. For example, the discard operation on a per-PDU set basis can be indicated by setting a specific parameter (e.g., pdu-SetDiscard) or setting pdu-SetDiscard to 'True'.

[0139] For example, when the discardTimer of a specific PDCP SDU of the terminal expires, the PDCP Entity of the terminal can behave as follows.

[0140] - If the PDU corresponding to the PDCP SDU belongs to a specific PDU Set, the PDCP SDU and the corresponding PDCP Data PDUs corresponding to all PDUs of the PDU Set can be discarded. For example, referring to FIG. 5, if the discardTimer of PDU X-1 of PDU Set X expires first compared to other PDUs (PDU X-2, PDU X-3), at the time point (540) when the discardTimer of PDU X-1 expires, the PDCP SDU and PDCP Data PDUs corresponding to all PDUs (PDU X-1, PDU X-2, PDU X-3) of PDU Set X can be discarded. For example, the PDU Set unit discard operation can be performed only when PSIHI is set for the QoS Flow to which the PDU Set belongs. For example, the PDU Set unit discard operation can be performed only when the base station has set pdu-SetDiscard for the corresponding PDCP Entity / DRB / QoS Flow. For example, the PDU Set unit discard operation can be performed only when the base station has set pdu-SetDiscard for the corresponding PDCP Entity / DRB / QoS Flow and PSIHI is set for the QoS Flow to which the corresponding PDU Set belongs.

[0141] - If the PDCP Data PDU for which the above discard instruction has been received has already been delivered to a lower layer (e.g., RLC layer), the lower layer can also be instructed to discard the corresponding PDCP Data PDU.

[0142] According to one embodiment, the base station may include, for each LCG (dsr-lcg) / LCH (dsr-lch), an identifier (e.g., SchedulingRequestId) indicating SR Configuration for DSR triggered by the corresponding LCG (dsr-lcg) / LCH (dsr-lch), in the configuration information of the corresponding LCG (dsr-lcg) / LCH (dsr-lch).

[0143] According to one embodiment, a new logical channel identifier (LCID) or extended LCID (eLCID) may be allocated in advance for the DSR MAC CE, and the LCID or eLCID field of the MAC Subheader of the DSR MAC CE transmitted by the terminal may be set to the allocated LCID or eLCID, thereby indicating that the MAC CE is a DSR MAC CE.

[0144] In one embodiment, in order to trigger a DSR or to set the Delay-Critical Buffer Size field and / or the (minimum) remaining time-based Buffer Size field reported via a DSR, the MAC Entity of a particular Cell Group of the UE may request the RLC Entity and the PDCP Entity corresponding to each LCH / LCG of that Cell Group about how much uplink data there is in the buffer of each Entity that satisfies a particular remaining time criterion.

[0145] In one embodiment, the buffer size indicated by the Delay-Critical buffer size field per LCH / LCG reported through DSR or the (minimum) remaining time buffer size field may mean the sum of uplink data that meets the remaining time criterion, excluding uplink data included in the MAC PDU including the DSR, among the uplink data in the entire RLC and PDCP buffers corresponding to the LCH / LCG.

[0146] For example, a particular PDU Set or a PDU belonging to a particular PDU Set meeting a particular remaining time criterion may mean that the remaining time of the first / earliest PDU in the PDU Set meeting the remaining time criterion meets the remaining time criterion.

[0147] For example, when calculating the buffer size indicated by the Delay-Critical Buffer Size field per LCH / LCG reported via DSR or the Buffer Size per (Minimum) Remaining Time field: if at least one PDU of a particular PDU Set has already arrived at the PDCP layer from an upper layer, and the remaining time of the first / earliest PDU of that PDU Set satisfies the remaining time criterion, then the PDU / PDU Segment in the RLC / PDCP buffer of that PDU Set may be included in the buffer size.

[0148] For example, when calculating the buffer size indicated by the Delay-Critical Buffer Size field per LCH / LCG reported via DSR or the Buffer Size per (Minimum) Remaining Time field: if all PDUs of a particular PDU Set have already arrived at the PDCP layer from upper layers, and the remaining time of the first / earliest PDU of that PDU Set meets the remaining time criterion, then the PDU / PDU Segment in the RLC / PDCP buffer of that PDU Set may be included in the buffer size.

[0149] For example, when calculating the buffer size indicated by the Delay-Critical buffer size field per LCH / LCG reported via DSR or the (minimum) remaining time-based buffer size field: a PDU / PDU Segment in the RLC / PDCP buffer of a PDU Set may be included in the buffer size if at least one PDU of that PDU Set has already arrived at the PDCP layer from an upper layer and PSIHI is set for the QoS Flow of that PDU Set or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow, and the remaining time of the first / earliest PDU of that PDU Set satisfies the remaining time criterion.

[0150] For example, when calculating the buffer size indicated by the Delay-Critical buffer size per LCH / LCG field or the (minimum) remaining time buffer size field reported via DSR: A PDU / PDU Segment in the RLC / PDCP buffer of a PDU Set may be included in the buffer size if the remaining time of the first / earliest PDU of the PDU Set satisfies the remaining time criteria, provided that all PDUs of the PDU Set have already arrived at the PDCP layer from upper layers and PSIHI is set for the QoS Flow of the PDU Set or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow of the PDU Set. For example, when calculating the buffer size indicated by the Delay-Critical buffer size per LCH / LCG field or the (minimum) remaining time buffer size field reported via DSR: At least one PDU of the PDU Set has already arrived at the PDCP layer from upper layers and PSIHI is set for the QoS Flow of the PDU Set or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow of the PDU Set. If the remaining time of the first / most PDU that arrived at the PDCP layer in the Set meets the remaining time criterion, and one or more PDUs in the PDU Set have not yet arrived at the PDCP layer, the PDUs in the PDU Set that have not yet arrived at the PDCP layer may also be included in the buffer size.

[0151] For example, when calculating the buffer size indicated by the Delay-Critical buffer size field per LCH / LCG reported via DSR or the (minimum) remaining time-based buffer size field: PDUs from a particular PDU Set that have not yet arrived at the PDCP layer may be included in the buffer size if: at least one PDU from that PDU Set has already arrived at the PDCP layer from an upper layer, and the remaining time of the first / earliest PDU from that PDU Set satisfies that remaining time criterion, and at least one PDU from that PDU Set has not yet arrived at the PDCP layer, and PSIHI is set for the QoS Flow of that PDU Set or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow.

[0152] For example, when a PDU that has not yet arrived at the PDCP layer is included in the buffer size indicated by the Delay-Critical buffer size field per LCH / LCG or the (minimum) remaining time buffer size field reported through DSR among the PDU Sets, the terminal can virtually create a PDCP SDU or PDCP Data PDU corresponding to the PDU by configuring the PDCP Entity and then include the size of the virtual PDCP SDU or PDCP Data PDU.

[0153] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: For a PDU Set where the remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion, the terminal can report the remaining time for that PDU Set if at least one PDU / PDU Segment of that PDU Set remains in the RLC / PDCP buffer.

[0154] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: if PSIHI is set for a QoS Flow of a specific PDU Set, or pdu-SetDiscard is set for a corresponding PDCP Entity / DRB / QoS Flow of that PDU Set, and the remaining time of the first / earliest PDU of that PDU Set satisfies the remaining time criterion, and at least one PDU / PDU Segment of that PDU Set remains in the RLC / PDCP buffer, the UE can report the remaining time for that PDU Set.

[0155] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: For a PDU Set where the remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion, the UE can report the remaining time for that PDU Set if at least one PDU / PDU Segment of that PDU Set remains in the RLC / PDCP buffer and all PDUs of that PDU Set have already arrived at the PDCP layer.

[0156] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: If there is a PDU Set whose remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion, the UE may not report the remaining time for the PDU Set if one or more PDUs of the PDU Set have not yet arrived at the PDCP layer. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the PDU Set.

[0157] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: a terminal may not report the remaining time for a PDU Set if: there is a PDU Set whose remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion; one or more PDUs of that PDU Set have not yet arrived at the PDCP layer; PSIHI is set for the QoS Flow of that PDU Set; or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow.

[0158] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: If there is a PDU Set whose remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion, the terminal can report the remaining time for that PDU Set even if one or more PDUs in that PDU Set have not yet arrived at the PDCP layer.

[0159] For example, when determining the (minimum) remaining time field per LCH / LCG reported via DSR: If there is a PDU Set whose remaining time of the first / earliest PDU that arrived at the PDCP layer satisfies the remaining time criterion, the UE can report the remaining time for that PDU Set only if PSIHI is set for the QoS Flow of that PDU Set or pdu-SetDiscard is set for the PDCP Entity / DRB / QoS Flow, even if one or more PDUs of that PDU Set have not yet arrived at the PDCP layer.

[0160] According to one embodiment of the present disclosure, a terminal can identify whether the total PDU Set size and PSIHI for a specific PDU Set of a specific QoS Flow are set according to the terminal implementation at the PDCP / RLC / MAC layer.

[0161] According to one embodiment of the present disclosure, the MAC / RLC layer of the terminal can be instructed from the PDCP layer on whether to set the total size of the PDU Set or PSIHI for a specific PDU Set of a specific QoS Flow.

[0162] According to one embodiment of the present disclosure, the MAC layer of a terminal may request the RLC layer to determine the amount of uplink data that satisfies a specific remaining time criterion. At this time, when the RLC layer determines the amount of uplink data that satisfies the remaining time criterion, at least one of the following uplink data may be included. For example, a PDU / PDU Set belonging to the following uplink data may be considered a PDU / PDU Set existing in an RLC buffer. For example, in the present disclosure, the remaining time criterion may mean a corresponding DSR trigger remaining time criterion or a corresponding DSR report remaining time criterion.

[0163] - RLC SDU and RLC SDU Segment that are not yet included in the RLC data PDU and satisfy the remaining time criterion. For example, if the PDU corresponding to the RLC SDU / SDU Segment belongs to a specific PDU Set, the RLC SDU / SDU Segment may be included in the amount of RLC layer uplink data that satisfies the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0164] - An RLC data PDU waiting for initial transmission and satisfying the remaining time criterion. For example, if the PDU corresponding to the RLC data PDU belongs to a specific PDU Set, the RLC data PDU may be included in the amount of RLC layer uplink data satisfying the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0165] - In RLC AM mode, an RLC data PDU waiting for RLC retransmission and satisfying the remaining time criterion. For example, if the PDU corresponding to the RLC data PDU belongs to a specific PDU Set, the RLC data PDU may be included in the amount of RLC layer uplink data satisfying the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0166] According to one embodiment, the method / method for determining whether a specific RLC SDU / SDU Segment / data PDU satisfies a specific remaining time criterion may be determined by the internal implementation of the terminal.

[0167] In one embodiment, the determination of whether a particular RLC SDU / SDU Segment / data PDU satisfies a particular remaining time criterion may be determined by an instruction from the corresponding PDCP Entity.

[0168] In one embodiment, the determination of whether a specific RLC SDU / SDU Segment / data PDU satisfies a specific remaining time criterion may be determined by whether the remaining time of the PDCP discardTimer of the RLC SDU / SDU Segment / data PDU satisfies the remaining time criterion. For example, the determination of the remaining time of the PDCP discardTimer of a specific RLC SDU / SDU Segment / data PDU may be determined by the internal implementation of the terminal.

[0169] In one embodiment, the MAC layer of a terminal may request the PDCP layer to determine the amount of uplink data that satisfies a specific remaining time criterion. At this time, when the PDCP layer determines the amount of uplink data that satisfies the remaining time criterion, it may include at least one of the following uplink data. For example, the PDU / PDU Set belonging to the following uplink data may be considered a PDU / PDU Set existing in the PDCP buffer.

[0170] - A PDCP SDU that has not yet formed a PDCP Data PDU and satisfies the remaining time criterion. For example, if the PDU corresponding to the PDCP SDU belongs to a specific PDU Set, the PDCP SDU may be included in the amount of PDCP layer uplink data that satisfies the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0171] - PDCP Data PDU that has not yet been delivered to the lower layer (MAC or RLC) and satisfies the remaining time criterion. For example, if the PDU corresponding to the PDCP Data PDU belongs to a specific PDU Set, the PDCP Data PDU may be included in the amount of PDCP layer uplink data that satisfies the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0172] - PDCP SDUs that are waiting for retransmission due to PDCP entity re-establishment in AM DRB and that satisfy the remaining time criterion. For example, if the PDU corresponding to the PDCP SDU belongs to a specific PDU Set, the PDCP SDU may be included in the amount of PDCP layer uplink data that satisfies the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at the PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0173] - PDCP Data PDU waiting for retransmission due to PDCP Data Recovery in AM DRB and satisfying the remaining time criterion. For example, if the PDU corresponding to the PDCP Data PDU belongs to a specific PDU Set, the PDCP Data PDU may be included in the amount of PDCP layer uplink data satisfying the remaining time criterion only if the remaining time of the PDCP SDU corresponding to the first / earliest PDU that arrived at PDCP in the PDU Set satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0174] - If the remaining time of the PDCP SDU corresponding to the first / most arrived PDU in a specific PDU Set satisfies the remaining time criterion, one or more PDUs belonging to the PDU Set that have not yet arrived at the PDCP layer may also be included in the amount of PDCP layer uplink data that satisfies the remaining time criterion. For example, the above operation may be performed only when PSIHI is set for the QoS Flow of the corresponding PDU Set or when pdu-SetDiscard is set for the corresponding PDCP Entity / DRB / QoS Flow of the corresponding PDU Set.

[0175] In one embodiment, when a PDCP entity that is associated with at least two RLC entities informs a MAC entity of an amount of PDCP data that satisfies a specific remaining time criterion, the PDCP entity may operate as follows.

[0176] - For RBs (radio bearers) with PDCP duplication activated:

[0177] ■ The amount of uplink data that satisfies the remaining time criteria of the PDCP Entity can be notified to the MAC Entity associated with the Primary RLC Entity.

[0178] ■ The remaining amount of uplink data, excluding PDCP Control PDUs, that satisfies the remaining time criteria of the PDCP Entity can be notified to the MAC Entity associated with the RLC Entity activated for the remaining PDCP duplications, excluding the Primary RLC Entity.

[0179] ■ The amount of uplink data that satisfies the remaining time criterion can be notified to the MAC entity associated with the RLC entity that has been deactivated for PDCP duplication.

[0180] - For RBs or DAPS (dual active protocol stack) bearers where PDCP duplication is deactivated:

[0181] ■ If a split secondary RLC entity is established, and the total amount of PDCP data that satisfies the remaining time criterion and the amount of RLC data for initial transmission in the primary RLC entity and the split secondary RLC entity is greater than or equal to a specific threshold set by the base station:

[0182] ◆ The amount of PDCP data that satisfies the remaining time criterion can be notified to both MAC entities associated with the Primary RLC entity and the Split Secondary RLC entity. For example, a PDCP entity can notify the amount of PDCP data that satisfies the remaining time criterion as 0 to a MAC entity associated with an RLC entity other than the Primary RLC entity and the Split Secondary RLC entity.

[0183] ■ If the transmitting PDCP entity is a DAPS bearer:

[0184] ◆ If uplink data switching is not requested:

[0185] ● The amount of PDCP data that satisfies the remaining time criteria can be notified to the MAC entity associated with the source cell.

[0186] ◆ When uplink data switching is requested:

[0187] ● The amount of PDCP data that satisfies the remaining time criteria can be notified to the MAC entity associated with the target cell.

[0188] ■ Otherwise:

[0189] ◆ It can inform the MAC entity associated with the Primary RLC Entity of the amount of PDCP data that satisfies the remaining time criteria.

[0190] ◆ The amount of PDCP data that satisfies the remaining time criterion can be notified as 0 to the MAC entity associated with other RLC entities except the Primary RLC Entity.

[0191] FIG. 6 is a diagram illustrating a procedure in which a base station and a terminal check whether a terminal supports DSR through RRC signaling and provide DSR-related settings according to one embodiment of the present disclosure.

[0192] Referring to FIG. 6, in step 620, the base station may transmit / send a UE Capability Enquiry message requesting a capability report to a terminal in an RRC_CONNECTED state. The base station may include a UE Capability request for each RAT (Radio Access Technology) type in the UECapabilityEnquiry message. The UE Capability request for each RAT type may include information on the requested frequency band. In addition, when the base station requests the generation of a UECapabilityInformation message from the terminal through the UECapabilityEnquiry message, the base station may include filtering information that can indicate conditions and restrictions. At this time, the base station may use the filtering information to indicate whether the terminal should report whether it supports DSR.

[0193] In step 630, the terminal may configure a terminal capability information (UECapabilityInformation) message corresponding to the UECapabilityEnquiry message and report a response to the UECapabilityEnquiry message to the base station. At this time, the UECapabilityInformation message may include a parameter / indicator indicating whether the terminal supports DSR. For example, the parameter or indicator may be 1-bit information. According to another embodiment, if the UECapabilityInformation message includes a parameter or indicator indicating that the terminal supports DSR, it may indicate that DSR is supported, and if it does not include the parameter or indicator, it may indicate that DSR is not supported.

[0194] The base station can determine whether the terminal supports DSR based on the received UECapabilityInformation message. If the base station determines that the terminal supports DSR, it can transmit DSR-related settings in an RRCReconfiguration message at step 640. The terminal can apply the DSR-related settings included in the received RRCReconfiguration message. The DSR-related settings can include all DSR-related settings that the base station can set for the terminal as described above in the present disclosure.

[0195] FIG. 7 is a diagram illustrating the structure of a terminal according to one embodiment of the present invention.

[0196] Referring to FIG. 7, the terminal (700) may include a transceiver (710), a control unit (720), and a storage unit (730). The transceiver (710), the control unit (720), and the storage unit (730) of the terminal (700) may operate according to at least one or a combination of methods corresponding to the above-described embodiments. In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0197] The transceiver (710) can transmit and receive signals with other network entities. The transceiver (710) can receive system information from a base station, for example, and can receive a synchronization signal or a reference signal.

[0198] The control unit (720) can control the overall operation of the terminal (700) according to the embodiment proposed in the present invention. For example, the control unit (720) can control the signal flow between each block to perform the operation according to the flowchart described above. Specifically, the control unit (720) can trigger the DSR according to the embodiment of the present invention or control the operation proposed in the present invention to transmit the DSR to the base station.

[0199] The storage unit (730) can store at least one of the information transmitted and received through the transmission and reception unit (710) and the information generated through the control unit (720).

[0200] FIG. 8 is a diagram illustrating the structure of a base station according to one embodiment of the present invention.

[0201] Referring to FIG. 8, the base station (800) may include a transceiver (810), a control unit (820), and a storage unit (830). The transceiver (810), the control unit (820), and the storage unit (830) of the base station (800) may operate according to at least one or a combination of methods corresponding to the above-described embodiments. In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0202] The transceiver (810) can transmit and receive signals with other network entities. The transceiver (810) can transmit system information to a terminal, for example, and can transmit a synchronization signal or a reference signal.

[0203] The control unit (820) can control the overall operation of the base station (800) according to the embodiment proposed in the present invention. For example, the control unit (820) can control the signal flow between each block to perform the operation according to the flowchart described above. Specifically, the control unit (820) can control the operation proposed in the present invention to transmit DSR setting information according to the embodiment of the present invention to the terminal, receive DSR from the terminal, or allocate uplink resources based on the received DSR.

[0204] The storage unit (830) can store at least one of the information transmitted and received through the transmission and reception unit (810) and the information generated through the control unit (820).

[0205] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are merely specific examples to easily explain the technical content of the present invention and facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical concept of the present invention are possible in addition to the embodiments disclosed herein. Furthermore, the above-described embodiments can be combined and operated as needed.

Claims

1. A method performed by a terminal of a wireless communication system, A step of receiving, from a base station, setting information indicating a remaining time threshold for triggering a DSR (delay status report); A step of triggering the DSR when the remaining time of the PDCP (packet data convergence protocol) discard timer of data buffered in the logical channel becomes less than the remaining time threshold; and Including a step of transmitting a MAC CE (medium access control-control element) for the above DSR to the base station, A method characterized in that the MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG (logical channel group) of the logical channel at the time of a first symbol for an initial PUSCH (physical uplink shared channel) transmission including the MAC CE.

2. In paragraph 1, A method characterized in that the above remaining time threshold is set for each LCG and has a unit of milliseconds.

3. In paragraph 1, A method characterized in that the MAC CE further includes a field indicating the LCG, a field indicating a buffer size of delay-critical data for the LCG, and a field indicating a buffer size table referenced by the field indicating the buffer size.

4. In paragraph 1, A method characterized in that the above DSR is triggered when there is no pending DSR for the logical channel.

5. A method performed by a base station of a wireless communication system, A step of transmitting configuration information indicating a remaining time threshold for triggering a DSR (delay status report) to a terminal; and If the remaining time of the PDCP (packet data convergence protocol) discard timer of data buffered in the logical channel of the terminal becomes smaller than the remaining time threshold, a step of receiving a MAC CE (medium access control-control element) for the DSR from the terminal is included. A method characterized in that the MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG (logical channel group) of the logical channel at the time of a first symbol for reception of an initial PUSCH (physical uplink shared channel) including the MAC CE.

6. In paragraph 5, A method characterized in that the above remaining time threshold is set for each LCG and has a unit of milliseconds.

7. In paragraph 5, A method characterized in that the MAC CE further includes a field indicating the LCG, a field indicating a buffer size of delay-critical data for the LCG, and a field indicating a buffer size table referenced by the field indicating the buffer size.

8. In paragraph 5, A method characterized in that the above DSR is triggered when there is no pending DSR for the logical channel in the terminal.

9. In the terminal of a wireless communication system, Transmitter and receiver; and comprising a control unit, said control unit comprising: Receives setting information indicating a remaining time threshold for triggering a DSR (delay status report) from a base station through the transceiver, If the remaining time of the PDCP (packet data convergence protocol) discard timer of data buffered in the logical channel becomes less than the remaining time threshold, the DSR is triggered. It is configured to transmit the MAC CE (medium access control-control element) for the above DSR to the base station through the transceiver, A terminal characterized in that the MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG (logical channel group) of the logical channel at the time of a first symbol for an initial PUSCH (physical uplink shared channel) transmission including the MAC CE.

10. In paragraph 9, A terminal characterized in that the above remaining time threshold is set for each LCG and has a unit of milliseconds.

11. In paragraph 9, A terminal, characterized in that the MAC CE further includes a field indicating the LCG, a field indicating a buffer size of delay-critical data for the LCG, and a field indicating a buffer size table referenced by the field indicating the buffer size.

12. In paragraph 9, A terminal characterized in that the above DSR is triggered when there is no pending DSR for the above logical channel.

13. In a base station of a wireless communication system, Transmitter and receiver; and comprising a control unit, said control unit comprising: Transmitting setting information indicating the remaining time threshold for triggering DSR (delay status report) to the terminal through the transceiver, When the remaining time of the PDCP (packet data convergence protocol) discard timer of data buffered in the logical channel of the terminal becomes smaller than the remaining time threshold, the MAC CE (medium access control-control element) for the DSR is configured to be received from the terminal through the transceiver, A base station, characterized in that the MAC CE includes a field indicating a value of a PDCP discard timer having a shortest remaining time for an LCG (logical channel group) of the logical channel at the time of a first symbol for initial PUSCH (physical uplink shared channel) reception including the MAC CE.

14. In paragraph 13, A base station, characterized in that the above remaining time threshold is set for each LCG and has a unit of milliseconds.

15. In paragraph 13, A base station, characterized in that the MAC CE further includes a field indicating the LCG, a field indicating a buffer size of delay-critical data for the LCG, and a field indicating a buffer size table referenced by the field indicating the buffer size.

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