Data processing method and device

Abstract

The present disclosure relates to a technique for efficiently processing application service data, and may provide a method and apparatus for a terminal to process data, the method comprising: a step of receiving an RRC message including information configured to transmit a discard status report indicating a gap of a PDCP serial number according to a discard of a PDCP SDU; a step of controlling compilation of a discard status report when the one or more PDCP SDUs are discarded and the discard status report is triggered; and a step of transmitting the discard status report.

Description

Technical Field

[0001] The present disclosure relates to a technology for efficiently processing application service data. Background Art

[0002] XR (Extended Reality) and CG (Cloud Gaming) are used as broad terms to represent various types of augmented, virtual, and mixed environments in human-machine and human-human communications performed with the help of handheld and wearable terminals. Extended Reality (XR) is used as a broad term covering Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR). Cloud gaming refers to a use case where most of the computation related to the game is dumped from the terminal to the edge or remote server. Together with cloud computing / gaming, XR applications usually require high throughput and low latency.

[0003] As mentioned above, as services change, mobile communication systems that support high-speed data rates and low-latency services are needed. To this end, QoS policy control for multimodal traffic, QoS processing support based on Protocol Data Unit Set (PDU Set), traffic assistance information transmission to support power consumption reduction, XR-specific capacity enhancement functions, etc. are being discussed.

[0004] In particular, the capacity boost function can increase the capacity of the radio interface by appropriately handling packets / PDUs that exceed the delay budget.

[0005] When packets with certain conditions are discarded, capacity can be effectively increased, but discarding causes reordering on the receiving side, which may increase latency, making it difficult to quickly process uplink data with priority. In addition, service interruptions may occur in an environment where the terminal is mobile.

[0006] Therefore, there is a need for a technology that can ensure capacity for processing application service data while minimizing the occurrence of problems caused by packet discard. Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present disclosure aims to provide a technology for effectively processing data of a terminal in a mobile communication network.

[0009] Solutions for solving problems

[0010] On the one hand, this embodiment can provide a method for a terminal to process data, including: a step of receiving an RRC message, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number based on the discard of a Packet Data Convergence Protocol Service Data Unit (PDCP SDU); a step of controlling the compilation of a discard status report when more than one PDCP SDU is discarded and the discard status report is triggered; and a step of transmitting the discard status report.

[0011] On the other hand, this embodiment can provide a method for a base station to control data processing of a terminal, comprising: a step of transmitting an RRC message to a terminal, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number based on the discard of a PDCP SDU; and a step of receiving a discard status report from a terminal when the terminal discards more than one PDCP SDU and triggers a discard status report.

[0012] On the other hand, this embodiment can provide a terminal device, which is a terminal for processing data, including: a receiving unit, receiving an RRC message, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number based on the discard of a PDCP SDU; a control unit, controlling the compilation of a discard status report when the discard status report is triggered by discarding more than one PDCP SDU; and a sending unit, transmitting the discard status report.

[0013] On the other hand, this embodiment can provide a base station device, which is a base station for controlling data processing of a terminal, including: a sending unit, transmitting an RRC message to the terminal, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number based on the discard of a PDCP SDU; and a receiving unit, receiving a discard status report from the terminal when the terminal discards one or more PDCP SDUs and triggers a discard status report.

[0014] Effects of the Invention

[0015] The present disclosure may provide a technology for efficiently processing data of a terminal in a mobile communication network. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram that simply shows the structure of an NR wireless communication system that is applicable to this embodiment.

[0017] Figure 2This is a diagram used to illustrate the frame structure in the NR system to which this embodiment is applicable.

[0018] Figure 3 This is a diagram for explaining a resource grid supporting a wireless access technology to which this embodiment is applicable.

[0019] Figure 4 This is a diagram for explaining a bandwidth portion supporting a wireless access technology to which this embodiment is applicable.

[0020] Figure 5 The figure exemplarily shows a synchronization signal block in a wireless access technology to which the present embodiment is applicable.

[0021] Figure 6 This is a diagram for explaining a random access procedure in a wireless access technology to which this embodiment is applicable.

[0022] Figure 7 This is a diagram for explaining CORESET.

[0023] Figure 8 is a flowchart for explaining terminal operation according to one embodiment.

[0024] Fig. 9 is a flowchart for illustrating the operation of a base station according to one embodiment.

[0025] Fig.10 is a diagram showing the composition of a terminal according to another embodiment.

[0026] Fig.11 is a diagram showing the composition of a base station according to another embodiment. DETAILED DESCRIPTION

[0027] Hereinafter, some embodiments of the present disclosure are described in detail with reference to the exemplary drawings. When assigning figure marks to the components of each figure, the same symbols may be assigned to the same components as much as possible even if they are displayed in different figures. In addition, when describing the present embodiment, if it is considered that the specific description of the relevant known structure or function will obscure the main idea of ​​the present technology, its detailed description may be omitted. In the case of "including", "having", "comprising" and the like mentioned in this specification, unless "only" is used, it means that other parts may be added. In the case of representing a component in the singular, the plural case may be included unless there is a special clear record.

[0028] In addition, when describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, sequence, or quantity of the component is not limited by the terms.

[0029] In the description of the positional relationship of components, if it is recorded that two or more components are "connected", "combined" or "accessed", the two or more components may be directly "connected", "combined" or "accessed", but it should be understood that other components may be "interposed" into the two or more components to thereby be "connected", "combined" or "accessed". Among them, other components may also be included in one or more of the two or more components that are "connected", "combined" or "accessed" to each other.

[0030] In the description of the time flow relationship related to components, operating methods or manufacturing methods, when the time sequence or process sequence is described by, for example, "after", "subsequently", "next", "before", etc., discontinuous situations may also be included unless "immediately" or "directly" is used.

[0031] On the other hand, when referring to the numerical value of a component or its corresponding information (for example, grade, etc.), even if there is no separate explicit description, the numerical value or its corresponding information should be interpreted as including the error range that may arise due to various factors (for example, process factors, internal or external impact, noise, etc.).

[0032] The wireless communication system in this specification refers to a system that uses wireless resources to provide various communication services such as voice and data packets. The system may include: terminals, base stations or core networks, etc.

[0033] The present embodiment disclosed below may be applicable to wireless communication systems using a variety of wireless access technologies. For example, the present embodiment may be applicable to a variety of wireless access technologies, such as: CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access) or NOMA (non-orthogonal multiple access). In addition, wireless access technology not only means a specific access technology, but also means various generations of communication technologies specified by various communication protocol organizations, such as: 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, ITU, etc. For example, CDMA can be implemented through wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented through wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented through wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi, wireless LAN), IEEE 802.16 (WiMAX, Worldwide Interoperability for Microwave Access), IEEE 802-20, E-UTRA (evolved UTRA), etc. IEEE 802.16m, as an evolution of IEEE 802.16e, provides backward compatibility with systems based on IEEE802.16e. UTRA is part of UMTS (universal mobile telecommunications system).3GPP (3rd generation partnership project) LTE (long term evolution) as a part of E-UMTS (evolved UMTS) using E-UTRA (evolved-UMTS terrestrial radio access), adopts OFDMA in the downlink and SC-FDMA in the uplink. As described above, the present embodiment may be applicable to currently disclosed or commercialized wireless access technologies, and may also be applicable to wireless access technologies currently being developed or to be developed in the future.

[0034] On the other hand, the terminal in this specification, as a comprehensive concept, refers to a device including a wireless communication module that communicates with a base station in a wireless communication system, and should be interpreted as not only including UE (User Equipment) in WCDMA (Wideband Code Division Multiple Access), LTE, NR (New Radio), HSPA (High Speed ​​Packet Access) and IMT-2020 (5G or New Radio), but also including MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), wireless device (wireless device) and the like in GSM. In addition, the terminal can be a user portable device such as a smartphone according to the usage form, and in a V2X (vehicle to everything, connected car technology) communication system, it can also mean a vehicle, a device including a wireless communication module in a vehicle, etc. In addition, in a machine type communication (Machine Type Communication) system, it can also mean an MTC terminal equipped with a communication module to perform mechanical type communication, an M2M (Machine to machine) terminal, and an URLLC (Ultra-Reliable Low-Latency Communications) terminal, etc.

[0035] The base station or cell in this specification refers to a terminal that communicates with the terminal in terms of the network, which means covering a variety of coverage areas, such as Node-B, eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), sector, site, various forms of antennas, BTS (Base Transceiver System, base station transmitter / receiver), access point, point (e.g., transmission point, receiving point, transmission / reception point), relay node, super large cell, macro cell, micro cell, micro cell, micro cell, RRH (Remote Radio Head), RU (Radio Unit), small cell, etc. In addition, the cell may mean a BWP (Bandwidth Part) in the frequency domain. For example, the serving cell may mean the Activation BWP of the terminal.

[0036] Since there are base stations controlling more than one cell in the various cells listed above, the base station can be interpreted in two ways. It can indicate: (1) the device itself, which provides a very large cell, macro cell, micro cell, pico cell, micro-micro cell or small cell related to the wireless area; (2) the wireless area itself. In case (1), all devices that interact so that the devices providing the specified wireless area are controlled by the same object or that configure the wireless area through collaboration are indicated as base stations. According to the configuration method of the wireless area, an embodiment of the base station is: point, transmission / reception point, transmission point, reception point, etc. In case (2), from the perspective of the user terminal or the standpoint of the adjacent base station, the wireless area itself that receives or sends signals can also be indicated as a base station.

[0037] In this specification, a cell may refer to a component carrier having coverage of a signal transmitted from a transmission / reception point or a coverage of a signal transmitted from a transmission / reception point (transmission point or transmission / reception point) or the transmission / reception point itself.

[0038] Uplink (UL, or uplink) means a way of sending / receiving data from a terminal to a base station, and downlink (DL, or downlink) means a way of sending / receiving data from a base station to a terminal. Downlink may mean communication or a communication path from multiple transmission / reception points to a terminal, and uplink may mean communication or a communication path from a terminal to multiple transmission / reception points. At this time, in the downlink, the transmitter may be part of the multiple transmission / reception points, and the receiver may be part of the terminal. In addition, in the uplink, the transmitter may be part of the terminal, and the receiver may be part of the multiple transmission / reception points.

[0039] The uplink and downlink transmit / receive control information through control channels such as PDCCH (Physical Downlink Control CHannel) and PUCCH (Physical Uplink Control Channel); transmit / receive data through data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel). In the following, the situation where signals are transmitted / received through channels such as PUCCH, PUSCH, PDCCH and PDSCH is also marked as "transmitting / receiving PUCCH, PUSCH, PDCCH and PDSCH".

[0040] For a clearer explanation, the following describes the technical concept mainly based on the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the technical features are not limited to this communication system.

[0041] In 3GPP, after studying 4G (4th-Generation, the fourth generation of mobile information system) communication technology, 5G (5th-Generation, the fifth generation of mobile information system) communication technology is being developed that meets the requirements of ITU-R for next-generation wireless access technology. Specifically, 3GPP develops new NR communication technology through 5G communication technology, which is different from LTE-A pro and 4G communication technology that improves LTE-Advanced technology in a manner that meets the requirements of ITU-R. LTE-A pro and NR both mean 5G communication technology. In the following, unless a specific communication technology is specifically mentioned, 5G communication technology will be explained with NR as the center.

[0042] The operation scenarios in NR add satellite, automotive and new vertical considerations to the existing 4G LTE scenarios, and define multiple operation scenarios. In terms of services, it supports eMBB (Enhanced Mobile Broadband) scenarios; mMTC (Massive Machine Communication) scenarios, which have high terminal density and are deployed over a wide range and require low data rates and asynchronous access; URLLC (Ultra Reliability and Low Latency) scenarios, which require high responsiveness and reliability and can support high-speed mobility.

[0043] In order to meet these scenarios, NR discloses a wireless communication system that applies new waveform and frame structure technology, low latency technology, ultra-high frequency band (mmWave) support technology, and forward compatible technology. In particular, in the NR system, in order to provide forward compatibility, a variety of technical changes are proposed in terms of flexibility. The main technical features of NR will be described below with reference to the accompanying drawings.

[0044] <Normal NR system>

[0045] Figure 1 This is a diagram simply showing the structure of the NR system applicable to this embodiment.

[0046] Reference Figure 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN (New Radio Radio Access Network) parts. NG-RAN (Next Generation Radio Access Network) consists of gNB and ng-eNB that provide the user plane (SDAP (Service Data Adaptation Protocol) / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC (Medium Access Control) / PHY (Physical Layer)) and the control plane (RRC) protocol termination for the UE (User Equipment). gNBs are interconnected with each other or gNB and ng-eNB are interconnected via the Xn interface. gNB and ng-eNB are connected to 5GC via the NG interface respectively. 5GC may include: AMF (Access and Mobility Management Function), which is responsible for the control plane such as terminal access and mobility control functions; and UPF (User Plane Function), which is responsible for user data control functions. NR supports both frequency bands below 6 GHz (FR1, Frequency Range 1) and above 6 GHz (FR2, Frequency Range 2).

[0047] gNB means a base station that provides NR user plane and control plane protocol termination to the terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to the terminal. The base station described in this specification should be understood to cover the meanings of gNB and ng-eNB, and can also be used according to the meaning of distinguishing gNB or ng-eNB as needed.

[0048] <Waveform, Parameter Set and Frame Structure in NR>

[0049] In NR, for downlink transmission, the CP-OFDM (Cyclic prefix Orthogonal Frequency Division Multiplexing) waveform with Cyclic prefix is used, and for uplink transmission, CP-OFDM or DFT-s-OFDM (Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing) is used. The OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and the advantages are high frequency efficiency and the ability to use a low-complexity receiver.

[0050] On the other hand, in NR, since the requirements for data speed, delay speed, coverage, etc. of the above three scenarios are different, it is necessary to effectively meet the requirements of each scenario through the frequency band that constitutes any NR system. To this end, a technology for effectively multiplexing wireless resources based on different multiple parameter sets (numerology) is proposed.

[0051] Specifically, the NR transmission parameter set is determined based on the sub-carrier spacing and CP (Cyclic prefix), as shown in Table 1 below. Taking 15kHz as the benchmark, the μ value is used as an exponential value of 2 and changes in an exponential form.

[0052]

Table 1

[0053]

[0054]

[0055] As shown in Table 1 above, according to the subcarrier spacing, the parameter set of NR can be divided into 5 types. This is different from the subcarrier spacing of LTE, one of the 4G communication technologies, which is fixed at 15kHz. Specifically, the subcarrier spacing used for data transmission in NR is 15kHz, 30kHz, 60kHz and 120kHz, and the subcarrier spacing used for synchronization signal transmission is 15kHz, 30kHz, 120kHz and 240kHz. In addition, the extended CP is only applicable to 60kHz subcarrier spacing. On the other hand, a frame with a length of 10ms is defined in the frame structure in NR, and the above frame consists of 10 subframes with the same length of 1ms. A frame can be divided into half frames of 5ms, each half frame includes 5 subframes. In the case of 15kHz subcarrier spacing, a subframe consists of a slot, and each slot consists of 14 OFDM symbols.

[0056] Figure 2 This is a diagram used to illustrate the frame structure in the NR system to which this embodiment is applicable.

[0057] Reference Figure 2In the case of normal CP, the time slot is fixedly composed of 14 OFDM symbols, but in the time domain of the time slot, the length can vary according to the subcarrier spacing. For example, in the case of a parameter set with a 15kHz subcarrier spacing, the length of the time slot is 1ms, which is the same as the length of the subframe. Differently, in the case of a parameter set with a 30kHz subcarrier spacing, although the time slot consists of 14 OFDM symbols, the length is 0.5ms, and two time slots can be included in one subframe. That is, subframes and frames are defined by a fixed time length, while the time slot is defined by the number of symbols, and the time length can vary according to the subcarrier spacing.

[0058] On the other hand, the basic unit of scheduling in NR is defined as a time slot. In order to reduce the transmission delay in the wireless interval, mini slots (or sub-slots or non-slot based schedules) are also introduced. If a wide subcarrier spacing is used, the length of a time slot will be inversely shortened, so the transmission delay in the wireless interval can be reduced. Mini slots (or sub-slots) are used to effectively support URLLC scenarios and can be scheduled in units of 2, 4, or 7 symbols.

[0059] In addition, unlike LTE, NR defines uplink and downlink resource allocation as symbol levels within a time slot. In order to reduce HARQ (hybrid automatic repeat request) delay, a time slot structure is defined in which HARQ ACK / NACK (hybrid automatic repeat request-acknowledgement / negative) can be directly sent within the transmission time slot, and this time slot structure is named self-contained structure for explanation.

[0060] NR is designed to support a total of 256 time slot formats, of which 62 time slot formats are used for 3GPP Rel-15. In addition, through the combination of various time slots, a common frame structure that constitutes an FDD or TDD frame is supported. For example, a time slot structure in which all symbols of the time slot are set to the downlink and a time slot structure in which all symbols are set to the uplink, as well as a time slot structure in which downlink symbols and uplink symbols are combined. In addition, NR supports data transmission to be scheduled in more than one time slot. Therefore, the base station can use a time slot format indicator (SFI) to notify the terminal whether the time slot is a downlink time slot, an uplink time slot or a flexible time slot. The base station can use SFI to indicate a table index formed by terminal-specific (UE-specific) RRC signaling to indicate the time slot format, or it can be dynamically indicated through DCI (Downlink Control Information) or statically or quasi-statically indicated through RRC.

[0061] <Physical Resources in NR>

[0062] Regarding the physical resources in NR, the antenna port, resource grid, resource element, resource block, bandwidth part, etc. can be considered.

[0063] The antenna port is defined as the channel carrying symbols on the antenna port can be inferred from the channel carrying other symbols on the same antenna port. If the large-scale property of the channel carrying symbols on one antenna port can be inferred from the channel carrying symbols on another antenna port, then the two antenna ports can be considered to have a QC / QCL (quasico-located or quasico-location) relationship. Among them, the large-scale properties include more than one of the following: Delay spread, Doppler spread, Frequency shift, Average received power, and Received Timing.

[0064] Figure 3 It is a diagram for explaining the resource grid of the radio access technology applicable to support this embodiment.

[0065] Refer to Figure 3 , Since NR supports multiple parameter sets in the same carrier, the resource grid can exist according to each parameter set. In addition, the resource grid can exist according to the antenna port, subcarrier spacing, and transmission direction.

[0066] The resource block consists of 12 subcarriers and is defined only in the frequency domain. In addition, the resource element consists of one OFDM symbol and one subcarrier. Therefore, as Figure 3 shown, the size of a resource block can vary according to the subcarrier spacing. In addition, NR defines "Point A" which serves as a common reference point for the resource block grid, common resource blocks, virtual resource blocks, etc.

[0067] Figure 4 It is a diagram for explaining the bandwidth part of the radio access technology applicable to support this embodiment.

[0068] In NR, unlike LTE where the carrier bandwidth is fixed at 20 MHz, the maximum carrier bandwidth for each subcarrier spacing is set to 50 MHz to 400 MHz. Therefore, it is not assumed that all terminals use these carrier bandwidths. Thus, in NR, as Figure 4 shown, a bandwidth part (BWP) can be specified within the carrier bandwidth for use by the terminal. In addition, the bandwidth part is associated with a parameter set and consists of a subset of consecutive common resource blocks and can be dynamically activated according to time. The terminal is configured to have up to 4 bandwidth parts for the uplink and downlink respectively and transmits / receives data using the activated bandwidth part within a specified time.

[0069] In the case of paired spectrum, the uplink and downlink bandwidth parts are set independently. In the case of unpaired spectrum, to prevent unnecessary frequency re-tuning between downlink and uplink operations, the downlink and uplink bandwidth parts are paired to share the center frequency.

[0070] <Initial Access in NR>

[0071] In NR, in order for a terminal to access a base station for communication, it performs cell search and random access procedures.

[0072] Cell search is a process that uses the synchronization signal block (SSB, Synchronization Signal Block) transmitted by the base station to synchronize the terminal with the cell of the above base station, obtain the physical layer cell ID, and obtain system information.

[0073] Figure 5 is a diagram exemplarily showing the synchronization signal block in the radio access technology to which the present embodiment can be applied.

[0074] Referring to Figure 5 , the SSB consists of a PSS (primary synchronization signal), which occupies 1 symbol and 127 subcarriers, an SSS (secondary synchronization signal), which also occupies 1 symbol and 127 subcarriers, and a PBCH that spans 3 OFDM symbols and 240 subcarriers.

[0075] The terminal receives the SSB by monitoring the SSB in the time and frequency domains.

[0076] SSB can be transmitted up to 64 times within 5ms. Most SSBs are transmitted in different transmission beams within 5ms. If the terminal uses a specific beam for transmission as a reference, it is assumed that SSB is transmitted once every 20ms and detection is performed. Within 5ms, the number of beams available for SSB transmission increases as the frequency band increases. For example, up to 4 SSB beams can be transmitted below 3GHz, up to 8 beams can be used in the frequency band from 3GHz to 6GHz, and up to 64 different beams can be used to transmit SSB in the frequency band above 6GHz.

[0077] SSB includes two in one time slot, and the starting symbol and the number of repetitions in the time slot are determined as follows according to the subcarrier spacing.

[0078] On the other hand, unlike the existing LTE SS, SSB will not be transmitted at the center frequency of the carrier bandwidth. That is, SSB can be transmitted at a place other than the center of the system frequency band, and when broadband operation is supported, multiple SSBs can be transmitted in the frequency domain. As a result, the terminal uses the synchronization raster as a candidate frequency position for monitoring SSB to monitor SSB. The carrier raster and the synchronization raster are redefined in NR as the center frequency position information of the channel for initial access, and the synchronization raster is set to a wider frequency interval than the carrier raster, so that the terminal can support fast SSB search.

[0079] The terminal can obtain the MIB (Master Information Block) through the PBCH of the SSB. The MIB (Master Information Block) includes the minimum information of the remaining minimum system information (RMSI, Remaining Minimum System Information) used by the terminal to receive network broadcasts. In addition, the PBCH may include: the position information of the first DM-RS symbol in the time domain, the information used by the terminal to monitor SIB1 (for example, SIB1 parameter set information, information related to SIB1 CORESET, search space information, and PDCCH-related parameter information, etc.), the offset information between the common resource block and the SSB (the absolute position of the SSB in the carrier is transmitted through SIB1), etc. Among them, the SIB1 parameter set information is also applicable to some messages used in the random access process for accessing the base station after the terminal completes the cell search process. For example, the parameter set information of SIB1 can be applicable to at least one of messages 1 to 4 used for the random access process.

[0080] The above-mentioned RMSI may mean SIB1 (System Information Block 1), which is broadcast periodically (for example, 160ms) in the cell. SIB1 includes the information required for the terminal to perform the initial random access procedure, and is periodically transmitted through PDSCH. In order to receive SIB1, the terminal needs to receive parameter set information for SIB1 transmission and CORESET (Control Resource Set) information for SIB1 scheduling through PBCH. The terminal uses SI-RNTI in CORESET to confirm the scheduling information for SIB1, and obtains SIB1 on PDSCH according to the scheduling information. Other SIBs except SIB1 can be transmitted periodically or according to the requirements of the terminal.

[0081] Figure 6 This is a diagram for explaining a random access procedure in a wireless access technology to which this embodiment is applicable.

[0082] Reference Figure 6 , when the cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted via PRACH. Specifically, the random access preamble is transmitted to the base station via PRACH consisting of continuous radio resources in a specific time slot that is repeated periodically. Generally, when the terminal initially accesses a cell, a contention-based random access procedure is performed, and when random access is performed for beam failure recovery (BFR, Beam Failure Recovery), a non-contention-based random access procedure is performed.

[0083] The terminal receives a random access response to the transmitted random access preamble. The random access response may include: a random access preamble identifier (ID), a UL Grant (uplink grant) (uplink radio resources), a temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and a TAC (Time Alignment Command). Since a random access response may include random access response information for more than one terminal, a random access preamble identifier may be included to notify which terminal the included UL Grant, temporary C-RNTI, and TAC are valid for. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the terminal to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, i.e., an RA-RNTI (Random Access-Radio Network Temporary Identifier).

[0084] The terminal that receives a valid random access response processes the information contained in the random access response and performs a transmission scheduled to the base station. For example, the terminal applies the TAC and stores the temporary C-RNTI. Additionally, the data stored in the terminal buffer or newly generated data is transmitted to the base station using the UL Grant. In this case, information capable of identifying the terminal should be included.

[0085] Finally, the terminal receives a downlink message for contention resolution.

[0086] <CORESET in NR>

[0087] The downlink control channel in NR is transmitted by a CORESET (Control Resource Set) with a length of 1 to 3 symbols and transmits uplink / downlink scheduling information and SFI (Slot format Index), TPC (Transmit Power Control) information, etc.

[0088] As mentioned above, in order to ensure the flexibility of the system, the concept of CORESET is introduced in NR. CORESET (Control Resource Set) refers to the time-frequency resources used for downlink control signals. The terminal can use more than one search space in the CORESET time-frequency resources to decode control channel candidates. A QCL (QuasiCoLocation) assumption is set for each CORESET, the purpose of which is to notify the characteristics of the simulated beam direction in addition to the characteristics based on the existing QCL assumption: delay spread, Doppler spread, Doppler shift and average delay.

[0089] Figure 7 This is a diagram for explaining CORESET (control resource set).

[0090] Reference Figure 7 , CORESET can exist in multiple forms within the carrier bandwidth in a time slot. In the time domain, a CORESET can consist of up to 3 OFDM symbols. In addition, a CORESET is defined as a multiple of six resource blocks up to the carrier bandwidth in the frequency domain.

[0091] The first CORESET is part of the initial bandwidth component and is indicated by the MIB to receive additional configuration information and system information from the network. After establishing a connection with the base station, the terminal can receive and configure more than one CORESET information through RRC signaling.

[0092] In this specification, frequency, frame, subframe, resource, resource block, region, frequency band, subband, control channel, data channel, synchronization signal, various reference signals, various signals or various messages related to NR (New Radio) may be interpreted as the meaning used in the past or present or multiple meanings used in the future.

[0093] XR (Extended Reality) is used as a broad term to represent various types of augmented, virtual, and hybrid environments in human-machine and human-human communications performed with the help of handheld and wearable terminals. Extended Reality (XR) is used as a broad term covering Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR). XR and interactive media application services such as cloud gaming, tactile / multimodal communication services require high data rates and low latency communications.

[0094] 3GPP is currently standardizing high-speed data transmission rates and low-latency services to support XR and interactive media application services in Rel-18. In order to effectively support XR and media services in mobile communication networks, QoS policy control for multimodal traffic, QoS processing support based on PDU Set, traffic assistance information transmission to support power consumption reduction, and XR-specific capacity enhancement functions are being discussed in the above standardization.

[0095] In particular, XR-specific capacity enhancements require the ability to increase the capacity of the radio interface by discarding packets / PDUs that exceed the above delay budget. Currently, the PDCP discard timer is used to model PDU Set discards, which does not properly handle data overflow situations.

[0096] Therefore, a technology for appropriately processing data in the event of data overflow is required. For example, in the event of overflow, discarding can be processed in consideration of the importance of the PDCP Set (PSI). However, a detailed process and operation method have not yet been proposed for this. In particular, since packet discarding causes reordering on the receiving side, delay may be increased, making it difficult to quickly process uplink data with priority. In addition, in an environment where the terminal is moving, service interruption may occur.

[0097] Since packet discarding of terminals that are sending and receiving XR and media application service data causes reordering at the base station, it is difficult to quickly process uplink data with priority. In addition, in an environment where the terminal is moving, service interruption may occur.

[0098] Under these viewpoints, the present disclosure proposes a technology for effectively controlling packet discarding of a terminal that is sending and receiving XR and media application service data.

[0099] The following describes a control method based on 5GS / NR technology. However, this is only for the sake of convenience, and the present invention is also applicable to any system / radio access technology (e.g., LTE, 6G). The embodiments described in the present invention include information elements and operation contents specified in the NR / 5GS specifications (e.g., MAC specifications: TS 38.321, NR RRC specifications: TS 38.331, system structure specifications: TS23.501, etc.). Even if the definition of the corresponding information elements and the related terminal operation contents are not described in this specification, the embodiments may also include the related contents specified in the standard specifications as known technologies.

[0100] Any function described below is defined as a separate terminal capability (UEradio capability, or UE Corenetwork capability), and can be transmitted by the terminal to the base station / core network individual (e.g., AMF / SMF) through corresponding signaling. Alternatively, any function is combined / combined and defined as the above terminal capability, and can be transmitted by the terminal to the base station / core network individual through corresponding signaling.

[0101] For any function or any combination of functions described below, the base station may transmit / indicate information indicating the permission / support / configuration of the above function / combination of functions to the terminal through an RRC message. For example, the above function / combination of functions may be indicated to the terminal before or while the above function / combination of functions is configured / applied. The above RRC message may be broadcast through system information. Alternatively, the above RRC message may be indicated to the terminal through a dedicated RRC message.

[0102] The base station may transmit / indicate information for limiting any function described below to the terminal through an RRC message. For example, a prohibition timer (Prohibit timer) of the above function may be indicated. Before starting the above function, or when starting the above function, the prohibition timer may be started / restarted. During the operation of the above timer, the terminal may be restricted from starting / executing the above function.

[0103] The functions described below can be performed independently. Furthermore, the functions and embodiments described below can be implemented in any combination / combination, which is obviously included in the scope of the present disclosure. For example, more than one function can be applied at the same time, or the embodiments of each part can be implemented by any combination.

[0104] On the other hand, any information about XR applications in this specification may be traffic characteristic information obtained / calculated / induced by statistics / empirical experience in the terminal / network (for example, expected value / average, deviation, standard deviation, minimum, maximum, and other arbitrary statistics / statistics). Therefore, any information contained in this specification may show one or more values ​​among the average (expected value) / minimum / maximum / standard deviation values. For example, if information called update rate is included, it may refer to the average (expected value) / minimum / maximum / standard deviation update rate. This is for ease of explanation, and all information in this specification may be used as statistical information. Alternatively, it may be information pre-configured in the terminal / network or supplied through OAM / application server / application function / UDM.

[0105] PDU Set, PDU Set QoS parameters, and PDU Set information are defined in 3GPP SA2 WG to effectively identify and process XR application data in Rel-18. PDU Set represents one or more PDUs carrying the payload of one unit of information generated at the application level (e.g., frame(s) or video slice(s) etc for XR Services). PDU Set Integrated Handling Information (PSIHI), one of the PDU Set QoS parameters, indicates whether all PDUs of the PDU Set are needed for the usage of PDU Set by application layer. PDU Set Importance (PSI) represents information used to identify the relative importance compared with other PDU Sets in a QoS flow.

[0106] In addition, in this specification, the report transmitted as the PDCP SDU is discarded in the sending PDCP individual and the PDCP sequence number (PDCP SN) gap is recorded as a discard status report for explanation. This is for the convenience of explanation, and the discard status report can be interpreted as the same as the PDU Set discard status report or the PDCP SN GAP report. That is, the discard status report refers to a report for notifying the GAP of the PDCP SN. This is a report that is distinguished from the PDCP status report.

[0107] The above terms are used for convenience of explanation and may be changed to any other names.

[0108] Figure 8 is a flowchart for explaining terminal operation according to one embodiment.

[0109] refer to Figure 8 The method for processing data by a terminal may include: a step of receiving an RRC message (S810), wherein the RRC message includes information configured to transmit a discard status report, wherein the discard status report indicates a gap in a PDCP sequence number according to discarding of a PDCP SDU.

[0110] For example, the terminal may receive information for transmitting a discard status report from the base station. The information configured to transmit the discard status report may be included in the RRC reconfiguration message. Alternatively, the information configured to transmit the discard status report may be included in the PDCP configuration information. The PDCP configuration information including the information configured to transmit the discard status report may be included in the RRC reconfiguration message.

[0111] As PDCP SDUs are discarded in a PDCP entity, the discard status report may indicate the gap information of the PDCP sequence number. Therefore, the discard status report may be named as a PDCP SN GAP report. Even if the name is replaced by a PDCP SN GAP report, the discard status report in this specification should be understood to have the same meaning.

[0112] For example, for a gap in a PDCP sequence number, when a gap occurs in the sequence number as a PDCP SDU is discarded, the gap information may be indicated.

[0113] The method for processing data by a terminal may include: when more than one PDCP SDU is discarded and a discard status report is triggered, controlling the step of compiling a discard status report (S820).

[0114] For example, the terminal may confirm whether a discard status report is triggered. As an example, a discard status report may be triggered when a PDCP SDU is discarded by a transmitting PDCP individual. As another example, a discard status report may be triggered when a PDCP SDU is discarded by a transmitting PDCP individual and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report may be triggered when a PDCP SDU is discarded by a transmitting PDCP individual and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)).

[0115] When triggering a discard status report, the terminal may compile a discard status report. For example, the terminal may set a value for a field to be included in the discard status report. As an example, the terminal may set a field (e.g., an FDC field) for indicating a COUNT value of a discarded PDCP SDU. The field (e.g., a First Discard Count (FDC) field) for indicating a COUNT value of a discarded PDCP SDU may indicate the smallest COUNT value among the COUNT values ​​associated with the discarded PDCP SDU. As another example, when there is more than one discarded PDCP SDU, the terminal may set a bitmap field for indicating it.

[0116] The terminal can compile by setting each field of the discard status report through the above operations.

[0117] The method for a terminal to process data may include: a step of transmitting a discard status report (S830).

[0118] For example, the discard status report may be transmitted via a PDCP control PDU having a PDU type field value that is distinguished from the PDCP status report. The PDU type field is a value used to indicate the type of control information of the PDCP control PDU. For example, the PDCP status report is set to a PDU type field with a value of 000 and transmitted. Differently, the discard status report may be set to a PDU type field with a value of 100 and transmitted. That is, the discard status report is transmitted via a PDCP control PDU and is set to a PDU type value different from that of the existing PDCP status report.

[0119] In addition, the discard status report may include a field (eg, FDC field) for indicating the COUNT value of the first discarded PDCP SDU. By indicating the COUNT value of the first PDCP SDU among the discarded PDCP SDUs, the start point of the GAP may be confirmed.

[0120] In addition, the discard status report may include a bitmap field indicating whether the PDCP SDU is discarded. For example, the bitmap field may indicate whether it is discarded according to different PDCP SDUs discarded in the transmitted PDCP individual. That is, the bitmap field indicates which SDUs are discarded and which SDUs are not discarded in the transmitted PDCP individual. The bit position of the Nth bit of the bitmap field is N. That is, the bit position of the first bit of the bitmap field is 1. For example, the bitmap field may indicate whether it is discarded with 1 bit for each PDCP SDU.

[0121] On the other hand, the bitmap field can be set to have a zero length. Of course, the length of the bitmap field can also be set to a length of more than 1 bit. That is, it can be selectively determined whether to include the bitmap field.

[0122] In addition, the bitmap field may be set to exclude the first discarded PDCP SDU but include the last discarded PDCP SDU and be allocated in multiples of 8 and have the same bit length as the number of COUNTs not exceeding the maximum size of 9000 bytes of the PDCP control PDU. For example, the bitmap field may not include the first PDCP SDU among more than one PDCP SDUs discarded in the transmitted PDCP individual. Because the first PDCP SDU can be indicated by the FDC field. The bitmap field may be set to include the last discarded PDCP SDU.

[0123] When the number of discarded PDCP SDUs is large, the bitmap field of each PDCP SDU is allocated in multiples of 8. For example, an octet configured by 8 bits can be added to the discard status report to configure the bitmap field. However, the discard status report is transmitted in the format of a PDCP control PDU. Therefore, the maximum size of the PDCP control PDU, 9000 bytes, cannot be exceeded. Taking this into account, the length of the bitmap field can be set to the same bit length as the number of COUNTs reached first in the following two cases: the operation of configuring and allocating octets to the discarded PDCP SDU in multiples of 8 and the state of reaching the maximum size of 9000 bytes of the PDCP control PDU. Here, whether 9000 bytes are reached can include the above-mentioned PDU type field, FDC field, etc. for calculation. That is, the bitmap field is set to configure the bitmap of the discarded PDCP SDUs other than the first discarded PDCP SDU, and the bitmap configuration is no longer performed when the maximum size of the PDCP control PDU, 9000 bytes, is reached.

[0124] The transmitting PDCP entity shall allocate a discard bitmap field whose length is the same as the number of COUNT values ​​reached first: from the first discarded PDCP SDU (excluding itself) to the last discarded PDCP SDU (including itself), rounded to the next multiple of 8, or to the size of the final PDCP Control PDU equal to 9000 bytes.

[0125] When uplink data is transmitted through the above operation, the discard information of the PDCP SDU can be transmitted to the base station through a separate discard status report. In order to effectively transmit data such as large-capacity XR, the PDCP SDU should be discarded quickly according to the importance of the PDCU Set. However, in this case, the system may cause a reordering operation, etc., which will further slow down the transmission speed. Therefore, the discard status report is transmitted together with the SDU discard operation using the PDU Set importance information, so that the discarded SN can be confirmed to prevent unnecessary reordering operations.

[0126] The operations on the base station side for the above operations are described below.

[0127] Fig. 9 is a flowchart for illustrating the operation of a base station according to one embodiment.

[0128] refer to Fig. 9 The method for controlling data processing of a terminal by a base station may include: a step of transmitting an RRC message to the terminal (S910), wherein the RRC message includes information configured to transmit a discard status report, wherein the discard status report indicates a gap in a PDCP sequence number according to discarding of a PDCP SDU.

[0129] For example, the base station may transmit information for transmitting a discard status report to the terminal. The information that the terminal is configured to transmit a discard status report may be included in an RRC reconfiguration message. Alternatively, the information configured to transmit a discard status report may be included in PDCP configuration information. The PDCP configuration information including the information configured to transmit a discard status report may be included in an RRC reconfiguration message.

[0130] As the PDCP SDU is discarded in the PDCP entity, the discard status report may indicate the gap information of the PDCP sequence number. For example, for the gap of the PDCP sequence number, when a gap occurs in the sequence number as the PDCP SDU is discarded, the above gap information may be indicated.

[0131] The method for a base station to control data processing of a terminal may include: when the terminal discards more than one PDCP SDU and triggers a discard status report, a step of receiving a discard status report from the terminal (S920).

[0132] When a terminal discards more than one PDCP SDU and triggers a discard status report, a discard status report can be compiled and generated. For example, the terminal can confirm whether the discard status report is triggered. As an example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU. As another example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report can be triggered when the discarded PDCP SDU(s) are not submitted to the lower layer by the RLC when the PDCP individual discards the PDCP SDU.

[0133] When triggering a discard status report, the terminal may compile a discard status report. For example, the terminal may set a value for a field to be included in the discard status report. As an example, the terminal may set a field (e.g., an FDC field) for indicating a COUNT value of a discarded PDCP SDU. The field (e.g., a First Discard Count (FDC) field) for indicating a COUNT value of a discarded PDCP SDU may indicate the smallest COUNT value among the COUNT values ​​associated with the discarded PDCP SDU. As another example, when there is more than one discarded PDCP SDU, the terminal may set a bitmap field for indicating it.

[0134] For example, the discard status report may be received via a PDCP control PDU having a PDU type field value that is distinguished from the PDCP status report. The PDU type field is a value used to indicate the control information type of the PDCP control PDU. For example, the PDCP status report is set to a PDU type field with a value of 000 and received. Differently, the discard status report may be set to a PDU type field with a value of 100 and received. That is, the discard status report is received via a PDCP control PDU and is set to a PDU type value different from that of the existing PDCP status report.

[0135] In addition, the discard status report may include a field (eg, FDC field) for indicating the COUNT value of the first discarded PDCP SDU. By indicating the COUNT value of the first PDCP SDU among the discarded PDCP SDUs, the start point of the GAP may be confirmed.

[0136] In addition, the discard status report may include a bitmap field indicating whether the PDCP SDU is discarded. For example, the bitmap field may indicate whether it is discarded according to different PDCP SDUs discarded in the transmitted PDCP individual. That is, the bitmap field indicates which SDUs are discarded and which SDUs are not discarded in the transmitted PDCP individual. The bit position of the Nth bit of the bitmap field is N. That is, the bit position of the first bit of the bitmap field is 1. For example, the bitmap field may indicate whether it is discarded with 1 bit for each PDCP SDU.

[0137] On the other hand, the bitmap field can be set to have a zero length. Of course, the length of the bitmap field can also be set to a length of more than 1 bit. That is, it can be selectively determined whether to include the bitmap field.

[0138] In addition, the bitmap field may be set to exclude the first discarded PDCP SDU but include the last discarded PDCP SDU and be allocated in multiples of 8 and have the same bit length as the number of COUNTs not exceeding the maximum size of 9000 bytes of the PDCP control PDU. For example, the bitmap field may not include the first PDCP SDU among more than one PDCP SDUs discarded in the transmitted PDCP individual. Because the first PDCP SDU can be indicated by the FDC field. The bitmap field may be set to include the last discarded PDCP SDU.

[0139] When the number of discarded PDCP SDUs is large, the bitmap field of each PDCP SDU is allocated in multiples of 8. For example, an octet configured by 8 bits can be added to the discard status report to configure the bitmap field. However, the discard status report is received in the format of a PDCP control PDU. Therefore, the maximum size of the PDCP control PDU, 9000 bytes, cannot be exceeded. Taking this into account, the length of the bitmap field can be set to the same bit length as the number of COUNTs reached first in the following two cases: the operation of configuring and allocating octets to the discarded PDCP SDU in multiples of 8 and the state of reaching the maximum size of the PDCP control PDU, 9000 bytes. Here, whether 9000 bytes are reached can include the above-mentioned PDU type field, FDC field, etc. for calculation. That is, the bitmap field is set to configure the bitmap of the discarded PDCP SDUs other than the first discarded PDCP SDU, and the bitmap configuration is no longer performed when the maximum size of the PDCP control PDU, 9000 bytes, is reached.

[0140] When the terminal transmits uplink data through the above operation, the base station can confirm the discard information of the PDCP SDU through a separate discard status report. In order to effectively transmit data such as large-capacity XR, the PDCP SDU should be discarded quickly according to the importance of the PDCU Set. However, in this case, the system may cause reordering operations, etc., which will further slow down the transmission speed. Therefore, the discard status report is transmitted together with the SDU discard operation using the PDU Set importance information, so that the discarded SN can be confirmed to prevent unnecessary reordering operations.

[0141] The present embodiment that can be performed by the above-mentioned terminal and base station will be described in more detail below. In particular, each operation and distinguishing embodiments are described below by recording more detailed embodiments. Each operation described below can be performed by the terminal and base station in any combination. In addition, each detailed embodiment described below can also be performed by the terminal and base station in any combination.

[0142] As described above, the discard status report described below can be replaced by the same terminology as PDCP SN GAP report, etc. In addition, the discard timer based on the importance of PDU Set can be described as a discard timer associated with PDU Set, a discard timer set to a value shorter / smaller than the existing PDCP discard timer, and a PDU Set discard timer, etc.

[0143] Status report transmission for PDU Set PDUs discarded

[0144] In order to handle the PDU Set-based discard function, the PDU Set discard indication information for the uplink can be indicated to the terminal through the PDCP configuration information included in the RRC reconfiguration message. For ease of explanation, the following PDU-Set-based discard function is used to indicate the function of discarding all / remaining / remaining packets / PDUs (or packets / PDUs of the indicated traffic / size / packet number ratio) in the above PDU Set when a PDU is discarded, and the name can be changed to any other name.

[0145] For example, the PDU Set discard indication information may indicate the PDU Set integration processing information. Alternatively, when the PDU Set integration processing information is set, the PDU Set discard indication information may allow the terminal to perform the PDU Set discard function. The PDU Set discard indication information may be set by the following information, which is used to indicate whether the terminal discards the PDUs of the PDU Set considering all PDUs of the PDU Set for the corresponding DRB for use by the application layer for the PDU Set.

[0146] For another example, the PDU Set discard indication information may be indicated as information distinguished from the PDU Set integration processing information. Alternatively, the PDU Set discard indication information may be indicated as information distinguished in a manner that enables the terminal to perform the PDU Set discard function when the PDU Set integration processing information is set.

[0147] For another example, the PDU Set discard indication information may be indicated as new / other PDU Set parameter information distinguished from the PDU Set integration processing information. As an example, the PDU level / ratio of the PDU Set required for use by the PDU Set performed by the application layer may be indicated. This is information used in the application layer for the above-mentioned PDU Set processing (for example, decoding, etc.), and for a PDU Set, it may be indicated by the ratio of the number of PDUs required for successful processing to the number of all PDUs included in the above-mentioned PDU Set, the ratio of the number of PDU Set Sequence Numbers required for successful processing to the number of (all) PDU Set Sequence Numbers associated with the above-mentioned PDU Set, or the ratio of the size (byte) of the PDU Set PDUs required for successful processing to the size (byte) of the (all) PDU Set PDUs associated with the above-mentioned PDU Set, etc.

[0148] If (at the base station / terminal) PDU-Set-integration-processing-information is set / configured / indicated for a QoS flow (or for more than one PDU-Set(s) contained in a QoS flow, or for a DRB associated with the above PDU Set through RRC signaling, or for a PDCP entity associated with the above PDU Set through RRC signaling, or for an upper layer of a QoS flow through NAS signaling), for a DRB with PDU Set discard indication information set, the terminal knows (or confirms) that the PDUs of the above level / ratio of a PDU-Set are lost, then it can be considered that the application layer no longer needs the remaining PDUs of the above PDU Set. And, in order to prevent unnecessary use of wireless resources, a discard operation can be performed. As another example, according to PDU SetImportance, it can be indicated with different weights. As another example, the PCF can determine the above PDU Set QoS parameters based on information provided by the application function (AF) and / or local configuration. The PDU Set QoS parameters are sent to the SMF as part of the PCC rules. The SMF sends it to the base station as part of the QoS file. If the base station receives the above parameters and supports the above parameters, the base station may be used for QoS processing based on PDU Set.

[0149] For another example, the PDU Set PDUs discard indication information may include information for indicating the availability (enable) / activation (activation) of the above-mentioned function. When the terminal sets / indicates / configures information for indicating the availability (enable) / activation (activation) of the above-mentioned function, the terminal (RRC of the terminal) may indicate the above-mentioned function (or the start / start of the above-mentioned function) to the lower layer (e.g., PDCP). And / or the terminal (RRC / PDCP of the terminal) may be configured to consider the above-mentioned function available / activated. Otherwise, the terminal (RRC / PDCP of the terminal) may be configured to consider the above-mentioned function unavailable (disable) / deactivated (deactivated).

[0150] For another example, the PDU Set discard indication information may be indicated by PDU Set discard timer information and / or PDU Set discard enable / activate information.

[0151] For another example, when a discard timer for a PDU included in a PDU-Set expires, the terminal may know (or may confirm) that a PDU of the above PDU-Set is lost. The base station may set the PDCP discard timer value in consideration of the (radio network's) PDU Set delay budget (PSDB: PDU Set Delay Budget (PSDB), the upper limit of the duration between the reception time of the first PDU (at the UPF for DL, at the UE for UL) and the time when all PDUs of the PDU Set have been successfully received (at the UE in DL, at the UPF in UL). A QoS flow is associated with only one PSDB, and when a QoS flow is available, it is applied to DL and UL, and replaces the PDB of the QoS flow). When the PDCP discard timer set to the above value expires, the terminal may consider the above PDCP SDU to be discarded as not meeting the PDU Set delay budget. The terminal may discard any / remaining / all / all stored / all non-discarded / all remaining / remaining non-discarded PDCP SDU(s) contained in the above PDU Set together with the above PDCP Data PDU(s). In the case that the PDCP discard timer for any / remaining / all / all stored / all / not discarded / remaining / not discarded PDCP SDU(s) contained in the above PDU Set has not expired, the terminal may also discard the above PDCP SDU(s) together with the above PDCP Data PDU(s). If the above PDCP Data PDU has been submitted to the lower layer, the above discard may be indicated to the lower layer.

[0152] If SDUs / PDUs are discarded at the terminal (base station) through any of the above functions, the terminal (base station) preferably indicates the discarded sequence number (SN) to the base station (terminal). The discarding of PDCP SDU(s) that have been associated with the PDCP SN by the terminal (or the transmitting PDCP entity of the terminal / base station) may cause an SN gap in the transmitted PDCP data PDUs of the terminal / base station. This may increase the PDCP reordering delay in the receiving PDCP entity of the base station / terminal. The terminal or base station may be delayed based on a variety of factors. In order to support the rapid processing of XR and media application data that requires low-latency and high-speed transmission, it is best to provide discarded information. In particular, during the switching process, the above information can be used to avoid unnecessary transmission / retransmission of discarded PDCP SDU / PDU, while reducing the reordering delay on the receiving side, thereby effectively sending and receiving PDCP data.

[0153] For example, a terminal (or a transmitting PDCP entity of the terminal) may trigger a discard status report. For ease of explanation, the status report including PDU Set PDUs or PDU or SDU discard information is marked as a discard status report below. This is for ease of explanation and may be replaced by any other term. As an example, a discard status report may be triggered in one or more of a PDCP entity reset request from an upper layer (RRC) and a PDCP data recovery request from an upper layer. As another example, a discard status report may be triggered when any discard timer associated with a PDU Set (or a discard timer of a PDU Set, or a PDCP discard timer of a PDCP SDU associated with a PDU Set) expires. As another example, a discard status report may be triggered when any discard timer associated with a PDU Set (or a discard timer of a PDU Set, or a PDCP discard timer of a PDCP SDU associated with a PDU Set) reaches a specific threshold indicated by a base station. As another example, a discard status report may be triggered when PDU Set PDUs discard based on PSI (PDU Set Importance) is set / configured / indicated by a base station. As another example, for DRBs configured to send discard status reports in uplink via RRC, the terminal (sending PDCP entity) may trigger a discard status report when the upper layer indicates one of PDCP reset and PDCP data resumption.

[0154] For another example, when a discard status report is triggered, the terminal (or the transmitting PDCP entity of the terminal) may generate / compile a discard status report. The terminal (or the transmitting PDCP entity of the terminal) may submit the discard status report to the lower layer in the first PDCP PDU for transmission.

[0155] For another example, when a PDCP status report in the prior art is triggered, the terminal (or the transmitting PDCP entity of the terminal) may compile a PDCP status report. The terminal (or the transmitting PDCP entity of the terminal) may submit the PDCP status report in the prior art to the lower layer in the first PDCP PDU used for transmission. The terminal (or the transmitting PDCP entity of the terminal) may submit the above discard status report to the lower layer in the second PDCP PDU used for transmission.

[0156] For another example, when a discard status report is triggered, the terminal (or the transmitting PDCP entity of the terminal) may compile a discard status report. For UM DRBs, the terminal (or the transmitting PDCP entity of the terminal) may submit the discard status report to the lower layer in the first PDCP PDU for transmission.

[0157] For another example, when a discard status report is triggered, the terminal (or the transmitting PDCP entity of the terminal) may compile a discard status report. If the PDCP status report in the prior art is not triggered (or not compiled, or the PDCP status report is not configured / set for the AM DRB (status report required (statusReportRequired)) to be sent), the discard status report may be submitted to the lower layer in the first PDCP PDU used for transmission.

[0158] For another example, the information for instructing to send a discard status report in the uplink may be set by the target base station and indicated to the terminal through the source base station.

[0159] For another example, when the terminal sends synchronization to the target cell and / or sends an RRC reconfiguration complete message to the target base station to complete the RRC switching procedure, the discard status report may include the above information in the RRC reconfiguration complete message and send it.

[0160] For another example, when the terminal sends synchronization to the target cell and / or sends an RRC reconfiguration completion message to the target base station to complete the RRC switching procedure, the discard status report can be sent together with the RRC reconfiguration completion message (or the first PUSCH of the DRB connected to the RRC reconfiguration completion message).

[0161] As another example, a terminal (or a transmitting RLC entity of the terminal) may trigger a discard status report. As an example, for a PDCP SDU(s) that has been submitted to the RLC by the PDCP layer, a discard status report may be triggered by a PDCP discard indication associated with a PDU Set discard. As another example, a discard status report may be triggered when any discard timer associated with a PDU Set (or a discard timer of a PDU Set, or a PDCP discard timer of a PDCP SDU associated with a PDU Set) expires. As another example, a discard status report may be triggered when any discard timer associated with a PDU Set (or a discard timer of a PDU Set, or a PDCP discard timer of a PDCP SDU associated with a PDU Set) reaches a specific threshold indicated by the base station. As another example, a discard status report may be triggered when PDU Set PDUs discard based on PSI (PDU Set Importance) is set / configured / indicated by the base station. As another example, for DRBs configured to send discard status reports in the uplink via RRC, the terminal (sending RLC entity) can trigger a discard status report when the PDCP layer indicates PDU Set discard.

[0162] For another example, when a discard status report is triggered, the terminal (or the transmitting RLC entity of the terminal) may generate / construct a discard status report. The terminal (or the transmitting RLC entity of the terminal) may create a discard status report at the first transmission opportunity indicated by the lower layer (e.g., MAC) and indicate it to the lower layer.

[0163] For another example, when a discard status report is triggered, the terminal (or the transmitting RLC entity of the terminal) may generate / construct a discard status report. If a prohibition timer for the above status report is being executed, the above prohibition timer expires, and the terminal (or the transmitting RLC entity of the terminal) may create a discard status report at the first transmission opportunity indicated by the lower layer (e.g., MAC) and indicate it to the lower layer.

[0164] For another example, even if the terminal (or the transmitting RLC entity of the terminal) receives a negative acknowledgement for the discarded RLC SDU, it may be considered as receiving a negative acknowledgement for the purpose of retransmitting the RLC SDU. For another example, even if the terminal (or the transmitting RLC entity of the terminal) receives a negative acknowledgement for the discarded RLC SDU, it may be considered as receiving a positive acknowledgement for the purpose of retransmitting the RLC SDU.

[0165] Discard Status Report Format

[0166] For example, the discard status report can reuse the PDCP Status report format. The above indication information can be transmitted via a PDCP Status report with a PDU type 000 value. As an example, in the FMC (First Missing COUNT) field indicating the COUNT value of the first lost PDCP SDU in the reordering window, the COUNT value of the first discarded PDCP SDU (or the first PDCP SDU of the first discarded PDU Set) can be included. As another example, for more than one PDCP SDU, bitmap field information that uses 0 or 1 to distinguish whether the above PDCP SDU is lost can be included for transmission. As another example, it can be transmitted without a bitmap field (this field indicates which SDUs are missing and which SDUs are correctly received in the receiving PDCP entity.), or the length of the bitmap field is set to 0. As another example, a bitmap field is allocated whose bit length is the same as the number of COUNTs reached first of the following two: excluding the first discarded PDCP SDU and including the last discarded PDCP SDU, from the first discarded PDCP SDU (excluding itself) to the last discarded PDCP SDU (including itself), rounded to the next multiple of 8, or to the size of the final PDCP Control PDU equal to 9000 bytes. The Nth bit position of the above bitmap can be used to distinguish whether the Nth SDU is discarded in the first discarded SDU.

[0167] As another example, for more than one PDU Set(s), bitmap field information for distinguishing whether a PDU included in the PDU Set is lost by 0 or 1 may be transmitted.

[0168] As another example, the allocation bitmap field has a bit length equal to the number of COUNTs reached first of the following two: excluding the first discarded PDU Set and including the last discarded PDU Set, from the first discarded PDU Set (excluding itself) to the last discarded PDU Set (including itself), rounded to the next multiple of 8, or to the size of the final PDCP Control PDU equal to 9000 bytes. The Nth bit position of the above bitmap can be used to distinguish whether the SDU included in the Nth PDU Set is discarded in the PDU Set with the first discarded SDU.

[0169] Alternatively, the discard status report may define a PDCP Control PDU (eg, having a value among PDU type 100-111) that is distinguished from the PDCP status report having a PDU type 000 value to transmit the above indication information.

[0170] As an example, the PDCP Control PDU may include a field (FDC field) for indicating the COUNT / HFN / PDCP_SN value of the first discarded PDCP SDU. As another example, the PDCP Control PDU may include a field for indicating the COUNT / HFN / PDCP_SN value of the last discarded PDCP SDU. As another example, the PDCP Control PDU may include a field for indicating the total / total number of discarded PDCP SDUs (or PDCP SDUs COUNTs) from the first discarded PDCP SDU to the last discarded PDCP SDU. As another example, the PDCP Control PDU may include a field for indicating the number of discarded PDCP SDUs (or PDCP SDUs COUNTs) (e.g., the number of all discarded PDCP SDUs - 1) from the first discarded PDCP SDU (excluding itself) to the last discarded PDCP SDU. As another example, the PDCP Control PDU may include a field for indicating the COUNT / HFN / PDCP_SN value of the PDCP SDU included in the first discarded PDU Set. As another example, the PDCP Control PDU may include a field for indicating the COUNT / HFN / PDCP_SN value of the PDCP SDU included in the last discarded PDU Set.

[0171] As another example, the PDCP Control PDU may include a field for indicating the number of PDCP SDUs included in the first discarded PDU Set to the last discarded PDU Set. As another example, a bitmap field information may be included for transmitting, for more than one PDCP SDU, using 0 or 1 to distinguish whether the PDCP SDU is lost. As another example, the transmission may be performed without a bitmap field or with the length of the bitmap field set to 0. As another example, a bitmap field is allocated, and its bit length is the same as the number of COUNTs reached first in the following two cases: excluding the first discarded PDCP SDU and including the last discarded PDCP SDU, from the first discarded PDCP SDU (excluding itself) to the last discarded PDCP SDU (including itself), rounded to the next multiple of 8, or to the size of the final PDCP control PDU equal to 9000 bytes. The position of the Nth bit of the above bitmap may be used to distinguish whether the Nth SDU is discarded in the first discarded SDU.

[0172] As another example, for more than one PDU Set(s), a bitmap field information may be transmitted using 0 or 1 to distinguish whether a PDU included in the above PDU Set is lost. As another example, a bitmap field is allocated, and its bit length is the same as the number of COUNTs reached first in the following two ways: excluding the first discarded PDU Set and including the last discarded PDU Set, from the first discarded PDU Set (excluding itself) to the last discarded PDU Set (including itself), rounded to the next multiple of 8, or to the size of the final PDCP control PDU equal to 9000 bytes. The Nth bit position of the above bitmap can be used to distinguish whether the SDU included in the Nth PDU Set is discarded in the PDU Set with the first discarded SDU.

[0173] Alternatively, the discard status report may define an RLC Control PDU (e.g., CPT value 001 or 000) to transmit the above indication information. As an example, the RLC Control PDU may include a field for indicating the SN (sequence number) value of the first discarded RLC (or RLC segment). As another example, the RLCControl PDU may include a field for indicating the SN value of the last discarded RLC SDUs (or RLC SDUs SNs). As another example, the RLC Control PDU may include a field for indicating the total / all discarded RLC SDUs (or RLC SDUs SNs) from the first discarded RLC SDU (or the above RLC segment) to the last discarded RLC SDU (or the above RLC segment). As another example, the RLC Control PDU may include a field for indicating the number of RLC SDUs (or RLC SDUs SNs) discarded from the first discarded RLC SDU (or the RLC segment) (excluding itself) to the last discarded RLC SDU (or the RLC segment) (e.g., the number of all discarded RLC SDUs - 1). As another example, the RLC Control PDU may include a field for indicating the SN value of the RLC SDU (or the RLC segment) included in the first discarded PDU Set. As another example, the RLC Control PDU may include a field for indicating the SN value of the RLC SDU (or the RLC segment) included in the last discarded PDU Set. As another example, the RLCControl PDU may include a field for indicating the number of RLC SDUs (or the RLC segment) included in the first discarded PDU Set to the last discarded PDU Set. As another example, for more than one RLC SDU, bitmap field information for distinguishing whether the RLC SDU is lost may be transmitted using 0 or 1. As another example, the bitmap field may be absent or the length of the bitmap field may be set to 0 for transmission.As another example, the allocation bitmap field has a bit length that is the same as the number of SNs reached first of the following two: excluding the first discarded RLC SDU and including the last discarded RLC SDU, from the first discarded RLC SDU (excluding itself) to the last discarded RLC SDU (including itself), rounded to the next multiple of 8, or to the size of the final RLC Control PDU equal to the bytes with a specific value.

[0174] PDU Set discard operation during switching

[0175] If (at the base station / terminal) PDU-Set-discard-indication information / PDU-Set-integration-processing-information is set / configured / indicated for a QoS flow (or for more than one PDU-Set(s) contained in a QoS flow, or for a DRB associated with the above PDU Set, or for a PDCP entity associated with the above PDU Set), and the terminal knows (or confirms) that a PDU of a PDU-Set is lost, it can be considered that the application layer no longer needs the remaining PDUs of the above PDU Set. In addition, in order to prevent unnecessary use of radio resources, a discard operation can be performed.

[0176] As an example, when receiving a PDCP status report, the terminal may perform a PDU Set discard function operation. The terminal (or the transmitting PDCP entity of the terminal) may know that a PDCP SDU / PDU having a COUNT value included in an FMC field value is lost. And / or the terminal (or the transmitting PDCP entity of the terminal) may know that a PDU Set (or a PDU / SDU of the above PDU Set) including a PDCP SDU / PDU having a COUNT value included in an FMC field value and a PDU Set (or a PDU / SDU of the above PDU Set) whose bitmap is set by 0 (or 1) are lost. A terminal configured with PDU-Set-discard-indication information / PDU-Set-integration-processing-information may discard the above PDCP SDU(s) for the DRB associated with the above PDU Set. The terminal may discard any / remaining / all / all stored / all non-discarded / all remaining / remaining non-discarded PDCP SDU(s) contained in the above PDU Set together with the above PDCP Data PDU(s). In the case that the PDCP discard timer for any / remaining / all / all stored / all / not discarded / remaining / not discarded PDCP SDU(s) contained in the above PDUSet has not expired, the terminal may also discard the above PDCP SDU(s) together with the above PDCP DataPDU(s). If the above PDCP data PDU has been submitted to the lower layer, the above discard may be indicated to the lower layer. Alternatively, if the above RLC entity is reset, the above discard is not indicated to the lower layer.

[0177] The following describes an embodiment in which the terminal resets the PDCP entity of the above-mentioned DRB when the RRC reconfiguration message includes reconfiguration with sync and key refresh information (and / or PDCP reset indication information (reestablishPDCP) is set for the above-mentioned DRB).

[0178] For another example, for an AM DRB (or for an AM DRB whose PDCP entity is not suspended), when transmission or retransmission is performed from the first PDCP SDU whose successful transmission of the above-mentioned PDCP Data PDU has not been confirmed by the lower layer to all PDCP SDUs that have been associated with the PDCP SN in ascending order of the COUNT value associated with the PDCP SDU before the PDCP entity is reset, transmission or retransmission of PDCP SDUs other than discarded PDCP SDUs may be performed.

[0179] For another example, for an AM DRB (or for an AM DRB whose PDCP entity is not suspended), for all PDCP SDUs that have been associated with the PDCP SN, from the first PDCP SDU whose successful transmission has not been confirmed by the lower layer to all PDCP SDUs that have been associated with the PDCP SN, transmission or retransmission of all PDCP SDUs that have not been discarded can be performed (according to the discard function of the PDU Set).

[0180] For another example, for an AM DRB (or for an AM DRB whose PDCP entity is not suspended), transmission or retransmission may be performed from the first PDCP SDU for which the PDCP discard timer (or the PDU Set discard timer associated with the PDCP SDU) has not expired (or is being executed) and for which the successful transmission of the PDCP Data PDU has not been confirmed by the lower layer to all PDCP SDUs already associated with the PDCP SN, in ascending order of the COUNT value associated with the PDCP SDU before the PDCP entity is reset.

[0181] For another example, the following steps may be performed: for an AM DRB (or for an AM DRB whose PDCP entity is not suspended), when executing (in ascending order of the COUNT value associated with the PDCP SDU before the PDCP entity is reset) the transmission or retransmission from the first PDCP SDU whose successful transmission of the above-mentioned PDCP Data PDU has not been confirmed by the lower layer to all PDCP SDUs that have been associated with the PDCP SN (or before execution), check whether the above-mentioned PDCP discard timer (or the PDU Set discard timer associated with the above-mentioned PDCP SDU) is being executed.

[0182] For another example, in the step of checking whether the PDCP discard timer (or the PDU Set discard timer associated with the PDCP SDU) is being executed when (or before) performing the transmission or retransmission of the first PDCP SDU whose successful transmission is not confirmed by the lower layer to all PDCP SDUs associated with the PDCP SN for an AM DRB (or for an AM DRB for which the PDCP entity is not suspended) from the first PDCP SDU whose successful transmission is not confirmed by the lower layer to the transmission or retransmission of all PDCP SDUs that have been associated with the PDCP SN (in ascending order of the COUNT value associated with the PDCP SDU before the PDCP entity is reset), for the PDCP SDU, if the PDCP discard timer (or the PDU Set discard timer associated with the PDCP SDU) expires, the terminal may discard the PDCP SDU. The terminal may discard any / remaining / all / all stored / all / non-discarded remaining / remaining non-discarded PDCP SDU(s) contained in the PDU Set together with the PDCP Data PDU(s). The terminal may maintain / store discard related information (e.g., PDU Set related information associated with the discarded PDCP SDU). When the terminal receives a PDCP SDU associated with / contained in (continuous with) the above-mentioned PDU Set(s) from an upper layer, the above-mentioned PDCP SDU is discarded (or, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Alternatively, the above-mentioned discard timer is set / configured / indicated to 0 for operation. Alternatively, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Since the above-mentioned PDCP SDU is discarded, the terminal (or the sending PDCP entity) does not associate the above-mentioned PDCP SDU with the (corresponding to TX_NEXT) COUNT value. For the above-mentioned PDCP SDU, the terminal (or the sending PDCP entity) does not perform more than one of the following: header compression, uplink data compression, integrity protection, ciphering, setting the PDCP SN of the PDCP Data PDU, incrementing TX_NEXT, and submitting the obtained PDCP Data PDU to the lower layer (increment TX_NEXT by on.submit the resulting PDCPDataPDU to lower layer), store the above PDCP SDU).

[0183] For another example, for an AM DRB (or for an AM DRB in which the PDCP entity is not suspended), for a first PDCP SDU whose successful transmission is not confirmed by the lower layer to all PDCP SDUs already associated with the PDCP SN, if the PDCP discard timer (or the PDU Set discard timer associated with the PDCP SDU) expires, the terminal may discard the PDCP SDU. The terminal may discard any / remaining / all / all stored / not discarded all / not discarded remaining / remaining not discarded PDCP SDU(s) contained in the PDU Set together with the PDCP Data PDU(s). The terminal may perform transmission or retransmission of the PDCP SDUs not discarded from the first PDCP SDU whose successful transmission is not confirmed by the lower layer to all PDCP SDUs already associated with the PDCP SN in ascending order of the COUNT value associated with the PDCP SDU before the PDCP entity is reset. The terminal may maintain / store discard-related information (e.g., PDU Set-related information associated with the discarded PDCP SDU). When the terminal receives a PDCP SDU associated with / containing (continuously) the above-mentioned PDU Set(s) from an upper layer, the terminal discards the above-mentioned PDCP SDU (or, without starting the discard timer associated with the above-mentioned PDCP SDU, discards the above-mentioned PDCP SDU. Alternatively, the above-mentioned discard timer is set / configured / indicated to 0 for operation. Alternatively, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded).

[0184] The following describes an embodiment of executing the PDCP data recovery process when the RRC reconfiguration message includes reconfiguration with sync but without key refresh information (and / or when PDCP data recovery indication information (recoverPDCP) is set for the above-mentioned DRB).

[0185] For another example, for an AM DRB, when retransmission is performed on all PDCP data PDUs that were successfully transmitted but not confirmed by the lower layers and submitted to the previously reset or released AM RLC entity (in ascending order of the associated COUNT value), retransmission of the PDCP data PDUs that were not discarded may be performed (based on the receipt of the status report).

[0186] For another example, the following steps may be performed: for AM DRB, when (or before) retransmitting all PDCP data PDUs that were successfully transmitted but not confirmed by the lower layer and submitted to the AM RLC entity that was previously reset or released (in ascending order of the associated COUNT value), check whether the above-mentioned PDCP discard timer (or the PDU Set discard timer associated with the above-mentioned PDCP SDU) is being executed.

[0187] For another example, when retransmitting (or before performing) all PDCP data PDUs that are successfully transmitted but not confirmed by the lower layer and submitted to the AM RLC entity that was previously reset or released (in ascending order of the associated COUNT value) for the AM DRB, in the step of checking whether the above-mentioned PDCP discard timer (or the PDU Set discard timer associated with the above-mentioned PDCP SDU) is being executed, for the above-mentioned PDCP SDU, if the PDCP discard timer (or the PDU Set discard timer associated with the above-mentioned PDCP SDU) expires, the terminal may discard the above-mentioned PDCP SDU. The terminal may discard any / remaining / all / all stored / all / non-discarded remaining / remaining non-discarded PDCP SDU(s) contained in the above-mentioned PDU Set together with the above-mentioned PDCP Data PDU(s). The terminal may maintain / store discard-related information (for example, PDU Set-related information associated with the discarded PDCP SDU). When the terminal receives a PDCP SDU associated with / containing (continuous with) the above-mentioned PDU Set(s) from an upper layer, the above-mentioned PDCP SDU is discarded (or, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Alternatively, the above-mentioned discard timer is set / configured / indicated to 0 for operation. Alternatively, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Since the above-mentioned PDCP SDU is discarded, the terminal (or the sending PDCP entity) does not associate the above-mentioned PDCP SDU with the (corresponding to TX_NEXT) COUNT value. For the above-mentioned PDCP SDU, the terminal (or the sending PDCP entity) does not perform more than one of the following: header compression, uplink data compression, integrity protection, ciphering, setting the PDCP SN of the PDCP Data PDU, incrementing TX_NEXT by 0, and submitting the obtained PDCP Data PDU to the lower layer (increment TX_NEXT by 0). on.submit the resulting PDCP DataPDU to lower layer), store the above PDCP SDU).

[0188] As another example, for AM DRB, (in ascending order of the associated COUNT value) for all PDCP data PDUs that are successfully transmitted but not confirmed by the lower layer and submitted to the AM RLC entity that was previously reset or released, retransmission of all PDCP data PDUs that are not discarded can be performed (according to the discard function of the PDU Set). The terminal can maintain / store discard-related information (for example, PDU Set-related information associated with the discarded PDCP SDU). When the terminal receives a PDCP SDU associated / contained (continuous) with the above-mentioned PDU Set(s) from the upper layer, the above-mentioned PDCP SDU is discarded (or, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Alternatively, the above-mentioned discard timer is set / configured / indicated to 0 for operation. Alternatively, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded).

[0189] For another example, for AM DRB, all PDCP data PDUs whose PDCP discard timer (or PDU Set discard timer associated with the above PDCP SDU) has not expired (or is being executed) and whose successful transmission has not been confirmed by the lower layer and submitted to the previously reset or released AM RLC entity may be retransmitted (in ascending order of the associated COUNT value).

[0190] As another example, for an AM DRB, (in ascending order of the associated COUNT value) for all PDCP data PDUs that are successfully transmitted but not confirmed by the lower layers and submitted to the AM RLC entity that was previously reset or released, if the above-mentioned PDCP discard timer (or the PDU Set discard timer associated with the above-mentioned PDCP SDU) expires, the terminal may discard the above-mentioned PDCP SDU. The terminal may discard any / remaining / all / all stored / not discarded all / not discarded remaining / remaining not discarded PDCP SDU(s) contained in the above-mentioned PDU Set together with the above-mentioned PDCP Data PDU(s). The terminal may retransmit all PDCP PDUs that are not discarded among all PDCP data PDUs that are successfully transmitted but not confirmed by the lower layers and submitted to the AM RLC entity that was previously reset or released. The terminal may maintain / store discard-related information (e.g., PDU Set-related information associated with the discarded PDCP SDU). When the terminal receives a PDCP SDU associated with / containing (continuous with) the above-mentioned PDU Set(s) from an upper layer, the above-mentioned PDCP SDU is discarded (or, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded. Or, the above-mentioned discard timer is set / configured / indicated to 0 for operation. Or, without starting the discard timer associated with the above-mentioned PDCP SDU, the above-mentioned PDCP SDU is discarded).

[0191] As described above, the present disclosure can effectively control the sending and receiving of data through signaling supporting discard processing. The following is an exemplary description of the operations of a terminal and a base station to which the above-mentioned embodiment can be applied.

[0192] Fig.10 is a diagram showing the composition of a terminal according to another embodiment.

[0193] refer to Fig.10 The terminal 1000 for processing data may include: a receiving unit 1030, receiving an RRC message, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number according to discarding of a PDCP SDU; a control unit 1010, controlling compilation of a discard status report when a discard status report is triggered by discarding more than one PDCP SDU; and a sending unit 1020, transmitting the discard status report.

[0194] For example, the receiving unit 1030 may receive information for transmitting a discard status report from a base station. The information configured to transmit a discard status report may be included in an RRC reconfiguration message. Alternatively, the information configured to transmit a discard status report may be included in PDCP configuration information. The PDCP configuration information including the information configured to transmit a discard status report may be included in an RRC reconfiguration message.

[0195] As the PDCP SDU is discarded in the PDCP entity, the discard status report may indicate the gap information of the PDCP sequence number. Therefore, the discard status report may be named as a PDCP SN GAP report. For example, for the gap of the PDCP sequence number, when a gap occurs in the sequence number as the PDCP SDU is discarded, the above gap information may be indicated.

[0196] The control unit 1010 can confirm whether a discard status report is triggered. As an example, a discard status report can be triggered when a transmitting PDCP individual discards a PDCP SDU. As another example, a discard status report can be triggered when a transmitting PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report can be triggered when a transmitting PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)).

[0197] The control unit 1010 may compile a discard status report when triggering a discard status report. For example, the control unit 1010 may set values ​​for fields to be included in the discard status report. As an example, the control unit 1010 may set a field (e.g., an FDC field) for indicating a COUNT value of a discarded PDCP SDU. The field (e.g., a First Discard Count (FDC) field) for indicating a COUNT value of a discarded PDCP SDU may indicate the smallest COUNT value among the COUNT values ​​associated with the discarded PDCP SDU. As another example, when there is more than one discarded PDCP SDU, the control unit 1010 may set a bitmap field for indicating it.

[0198] The control unit 1010 may set each field of the discard status report for compilation through the above operation.

[0199] For example, the discard status report may be transmitted via a PDCP control PDU having a PDU type field value that is distinguished from the PDCP status report. The PDU type field is a value used to indicate the type of control information of the PDCP control PDU. For example, the PDCP status report is set to a PDU type field with a value of 000 and transmitted. Differently, the discard status report may be set to a PDU type field with a value of 100 and transmitted. That is, the discard status report is transmitted via a PDCP control PDU and is set to a PDU type value different from that of the existing PDCP status report.

[0200] In addition, the discard status report may include a field (eg, FDC field) for indicating the COUNT value of the first discarded PDCP SDU. By indicating the COUNT value of the first PDCP SDU among the discarded PDCP SDUs, the start point of the GAP may be confirmed.

[0201] In addition, the discard status report may include a bitmap field indicating whether the PDCP SDU is discarded. For example, the bitmap field may indicate whether it is discarded according to different PDCP SDUs discarded in the transmitted PDCP individual. That is, the bitmap field indicates which SDUs are discarded and which SDUs are not discarded in the transmitted PDCP individual. The bit position of the Nth bit of the bitmap field is N. That is, the bit position of the first bit of the bitmap field is 1. For example, the bitmap field may indicate whether it is discarded with 1 bit for each PDCP SDU.

[0202] On the other hand, the bitmap field can be set to have a zero length. Of course, the length of the bitmap field can also be set to a length of more than 1 bit. That is, it can be selectively determined whether to include the bitmap field.

[0203] In addition, the bitmap field may be set to exclude the first discarded PDCP SDU but include the last discarded PDCP SDU and be allocated in multiples of 8 and have the same bit length as the number of COUNTs not exceeding the maximum size of 9000 bytes of the PDCP control PDU. For example, the bitmap field may not include the first PDCP SDU among more than one PDCP SDUs discarded in the transmitted PDCP individual. Because the first PDCP SDU can be indicated by the FDC field. The bitmap field may be set to include the last discarded PDCP SDU.

[0204] When the number of discarded PDCP SDUs is large, the bitmap field of each PDCP SDU is allocated in multiples of 8. For example, an octet configured by 8 bits can be added to the discard status report to configure the bitmap field. However, the discard status report is transmitted in the format of a PDCP control PDU. Therefore, the maximum size of the PDCP control PDU, 9000 bytes, cannot be exceeded. Taking this into account, the length of the bitmap field can be set to the same bit length as the number of COUNTs reached first in the following two cases: the operation of configuring and allocating octets to the discarded PDCP SDU in multiples of 8 and the state of reaching the maximum size of 9000 bytes of the PDCP control PDU. Here, whether 9000 bytes are reached can include the above-mentioned PDU type field, FDC field, etc. for calculation. That is, the bitmap field is set to configure the bitmap of the discarded PDCP SDUs other than the first discarded PDCP SDU, and the bitmap configuration is no longer performed when the maximum size of the PDCP control PDU, 9000 bytes, is reached.

[0205] When transmitting uplink data through the above operation, the terminal 1000 may transmit the discard information of the PDCP SDU to the base station through a separate discard status report.

[0206] Furthermore, the control section 1010 controls the operation of the entire terminal 1000 according to the data processing operation required to perform the above-described present embodiment.

[0207] The sending unit 1020 and the receiving unit 1030 are used to send and receive signals, messages and data required to execute the above embodiment with the base station.

[0208] Fig.11 is a diagram showing the composition of a base station according to another embodiment.

[0209] refer to Fig.11 The base station 1100 for controlling data processing of the terminal may include: a sending unit 1120, which transmits an RRC message to the terminal, the RRC message including information configured to transmit a discard status report, the discard status report indicating a gap in a PDCP sequence number based on discarding of the PDCP SDU; and a receiving unit 1130, which receives a discard status report from the terminal when the terminal discards more than one PDCP SDU and triggers a discard status report.

[0210] For example, the transmitting unit 1120 may transmit information for transmitting a discard status report to the terminal. The information that the terminal is configured to transmit a discard status report may be included in an RRC reconfiguration message. Alternatively, the information configured to transmit a discard status report may be included in PDCP configuration information. The PDCP configuration information including the information configured to transmit a discard status report may be included in an RRC reconfiguration message.

[0211] As the PDCP SDU is discarded in the PDCP entity, the discard status report may indicate the gap information of the PDCP sequence number. For example, for the gap of the PDCP sequence number, when a gap occurs in the sequence number as the PDCP SDU is discarded, the above gap information may be indicated.

[0212] On the other hand. When a discard status report is triggered by discarding more than one PDCP SDU, the terminal can compile and generate a discard status report. For example, the terminal can confirm whether the discard status report is triggered. As an example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU. As another example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report can be triggered when a PDCP individual discards a PDCP SDU and there is at least one stored PDCP SDU(s) associated with a COUNT value (greater than the COUNT value associated with the discarded PDCP SDU(s)). As another example, a discard status report can be triggered when the discarded PDCP SDU(s) are not submitted to the lower layer by the RLC when the PDCP SDU(s) are discarded.

[0213] When triggering a discard status report, the terminal may compile a discard status report. For example, the terminal may set a value for a field to be included in the discard status report. As an example, the terminal may set a field (e.g., an FDC field) for indicating a COUNT value of a discarded PDCP SDU. The field (e.g., a First Discard Count (FDC) field) for indicating a COUNT value of a discarded PDCP SDU may indicate the smallest COUNT value among the COUNT values ​​associated with the discarded PDCP SDU. As another example, when there is more than one discarded PDCP SDU, the terminal may set a bitmap field for indicating it.

[0214] For example, the discard status report may be received via a PDCP control PDU having a PDU type field value that is distinguished from the PDCP status report. As an example, the discard status report may be received with the PDU type field set to a value of 100. That is, the discard status report is transmitted via a PDCP control PDU and is set to a PDU type value that is different from the existing PDCP status report.

[0215] In addition, the discard status report may include a field (eg, FDC field) for indicating the COUNT value of the first discarded PDCP SDU. By indicating the COUNT value of the first PDCP SDU among the discarded PDCP SDUs, the start point of the GAP may be confirmed.

[0216] In addition, the discard status report may include a bitmap field indicating whether the PDCP SDU is discarded. For example, the bitmap field may indicate whether it is discarded according to different PDCP SDUs discarded in the transmitted PDCP individual. That is, the bitmap field indicates which SDUs are discarded and which SDUs are not discarded in the transmitted PDCP individual. The bit position of the Nth bit of the bitmap field is N. That is, the bit position of the first bit of the bitmap field is 1. For example, the bitmap field may indicate whether it is discarded with 1 bit for each PDCP SDU.

[0217] On the other hand, the bitmap field can be set to have a zero length. Of course, the length of the bitmap field can also be set to a length of more than 1 bit. That is, it can be selectively determined whether to include the bitmap field.

[0218] In addition, the bitmap field may be set to exclude the first discarded PDCP SDU but include the last discarded PDCP SDU and be allocated in multiples of 8 and have the same bit length as the number of COUNTs not exceeding the maximum size of 9000 bytes of the PDCP control PDU. For example, the bitmap field may not include the first PDCP SDU among more than one PDCP SDUs discarded in the transmitted PDCP individual. Because the first PDCP SDU can be indicated by the FDC field. The bitmap field may be set to include the last discarded PDCP SDU.

[0219] When the number of discarded PDCP SDUs is large, the bitmap field of each PDCP SDU is allocated in multiples of 8. For example, an octet configured by 8 bits can be added to the discard status report to configure the bitmap field. However, the discard status report is received in the format of a PDCP control PDU. Therefore, the maximum size of the PDCP control PDU, 9000 bytes, cannot be exceeded. Taking this into account, the length of the bitmap field can be set to the same bit length as the number of COUNTs reached first in the following two cases: the operation of configuring and allocating octets to the discarded PDCP SDU in multiples of 8 and the state of reaching the maximum size of the PDCP control PDU, 9000 bytes. Here, whether 9000 bytes are reached can include the above-mentioned PDU type field, FDC field, etc. for calculation. That is, the bitmap field is set to configure the bitmap of the discarded PDCP SDUs other than the first discarded PDCP SDU, and the bitmap configuration is no longer performed when the maximum size of the PDCP control PDU, 9000 bytes, is reached.

[0220] Furthermore, the control section 1110 controls the operation of the entire base station 1100 according to the data processing operation required to perform the above-described present embodiment.

[0221] The sending unit 1120 and the receiving unit 1130 are used to send and receive signals, messages and data required to execute the above-mentioned embodiment with the terminal.

[0222] The above embodiment may be supported by a standard document disclosed in at least one of IEEE 802, 3GPP and 3GPP2 as wireless access systems. That is, in this embodiment, steps, components, and parts that are not described in order to clearly reveal the technical concept may be supported by the above standard documents. In addition, all terms disclosed in this specification may be interpreted by the above standard documents.

[0223] The above-mentioned embodiment can be implemented by various means. For example, the embodiment can be implemented by hardware, firmware, software or a combination thereof.

[0224] In the case of hardware implementation, the method according to the present embodiment can be implemented by one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers or microprocessors, etc.

[0225] In the case of implementation by firmware or software, the method according to this embodiment can be implemented in the form of a device, process or function that performs the functions or operations described above. The software code can be stored in a storage unit and driven by a processor. The storage unit is located inside or outside the processor and can exchange data with the processor through a variety of known devices.

[0226] In addition, the above-mentioned terms such as "system", "processor", "controller", "component", "module", "interface", "model" or "unit" may generally refer to physical hardware related to a computer, a combination of hardware and software, software or running software. For example, the aforementioned components may be processes driven by a processor, processors, controllers, control processors, individuals, execution threads, programs and / or computers, but are not limited to these. For example, an application running in a controller or processor and the controller or processor may become components. More than one component may be located in a process and / or execution thread, and a component may be located in one device (such as a system, a computing device, etc.) or distributed in two or more devices.

[0227] The above description is only an exemplary description of the technical idea of ​​the present disclosure, and technicians in the field of the present disclosure can make various modifications and changes without departing from the essential features of the technical idea. In addition, the present embodiment is to illustrate the technical idea of ​​the present disclosure rather than to limit it, and therefore, the scope of the technical idea is not limited by these embodiments. The scope of protection of the present disclosure should be interpreted in accordance with the following claims, and all technical ideas within the equivalent scope thereof should be interpreted as included in the scope of rights of the present disclosure.

Claims

1. A method for processing data by a terminal, comprising: The step of receiving a radio resource control message, the radio resource control message including information configured to transmit a discard status report, the discard status report indicating a gap in a packet data convergence protocol sequence number based on discarding of a packet data convergence protocol service data unit; When more than one packet data convergence protocol service data unit is discarded to trigger the discard status report, controlling the step of compiling the discard status report; as well as The step of transmitting said discard status report.

2. The method according to claim 1, wherein: The information configured to transmit the discard status report is included in the packet data convergence protocol configuration information.

3. The method according to claim 1, wherein: The discard status report is transmitted via a packet data convergence protocol control protocol data unit having a protocol data unit type field value that is distinguished from a packet data convergence protocol status report.

4. The method according to claim 1, wherein: The discard status report includes a field for indicating a count value of a first discarded packet data convergence protocol service data unit.

5. The method according to claim 1, wherein: The discard status report includes a bitmap field indicating whether a packet data convergence protocol service data unit is discarded.

6. The method according to claim 5, wherein: The bitmap field is set to have zero length.

7. The method according to claim 5, wherein: The bitmap field is set to exclude the first discarded packet data convergence protocol service data unit and include the last discarded packet data convergence protocol service data unit, and is allocated in multiples of 8, And has the same bit length as the count number not exceeding the maximum size of 9000 bytes of the packet data convergence protocol control protocol data unit.

8. A method for a base station to control data processing of a terminal, comprising: The step of transmitting a radio resource control message to the terminal, the radio resource control message including information configured to transmit a discard status report, the discard status report indicating a gap in a packet data convergence protocol sequence number based on discarding of a packet data convergence protocol service data unit; as well as When the terminal discards more than one packet data convergence protocol service data unit and triggers the discard status report, a discard status report is received from the terminal.

9. The method according to claim 8, wherein: The information configured to transmit the discard status report is included in the packet data convergence protocol configuration information.

10. The method according to claim 8, wherein: The discard status report is received via a packet data convergence protocol control protocol data unit having a protocol data unit type field value that is distinguished from a packet data convergence protocol status report.

11. The method according to claim 8, wherein: The discard status report includes at least one of a field for indicating a count value of a first discarded packet data convergence protocol service data unit and a bitmap field indicating whether the packet data convergence protocol service data unit is discarded.

12. The method according to claim 11, wherein: The bitmap field is set to have zero length.

13. The terminal according to claim 11, wherein: The bitmap field is set to exclude the first discarded packet data convergence protocol service data unit and include the last discarded packet data convergence protocol service data unit, and is allocated in multiples of 8, And has the same bit length as the count number not exceeding the maximum size of 9000 bytes of the packet data convergence protocol control protocol data unit.

14. A terminal for processing data, comprising: a receiving unit, receiving a radio resource control message, the radio resource control message including information configured to transmit a discard status report, the discard status report indicating a gap in a packet data convergence protocol sequence number based on discarding of a packet data convergence protocol service data unit; a control unit, which controls compiling the discard status report when more than one packet data convergence protocol service data unit is discarded to trigger the discard status report; and A sending unit transmits the discard status report.

15. The terminal according to claim 14, wherein: The information configured to transmit the discard status report is included in the packet data convergence protocol configuration information.

16. The terminal according to claim 14, wherein: The discard status report is transmitted via a packet data convergence protocol control protocol data unit having a protocol data unit type field value that is distinguished from a packet data convergence protocol status report.

17. The terminal according to claim 14, wherein: The discard status report includes a field for indicating a count value of a first discarded packet data convergence protocol service data unit.

18. The terminal according to claim 14, wherein: The discard status report includes a bitmap field indicating whether a packet data convergence protocol service data unit is discarded.

19. The terminal according to claim 18, wherein: The bitmap field is set to have zero length.

20. The terminal according to claim 18, wherein: The bitmap field is set to exclude the first discarded packet data convergence protocol service data unit and include the last discarded packet data convergence protocol service data unit, and is allocated in multiples of 8, And has the same bit length as the count number not exceeding the maximum size of 9000 bytes of the packet data convergence protocol control protocol data unit.

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