Terminal device, method for terminal device, and base station device

Abstract

A terminal device (10) receives a radio resource control (RRC) message containing information for configuring a first timer to be used for data discarding, receives an RRC message containing information for configuring a second timer, and starts the first timer or the second timer on the basis of configuration information indicating the enabling or disabling of a discard process based on protocol data unit set importance (PSI).

Description

Terminal device, terminal device method, and base station device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2023-167798, filed on September 28, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a terminal device, a terminal device method, and a base station device.

[0003] In recent years, technological development related to extended reality (XR) has progressed. XR is a concept that includes multimedia integration technologies such as virtual reality (VR), augmented reality (AR), mixed reality (MR), and substitutional reality (SR). In XR, three-dimensional time-series image data in real space and / or virtual space, audio data of multiple channels (stereo, 5.1ch, etc.), other data presented to the user, control data, etc. are transmitted and received in parallel. XR requires low latency and high reliability to maintain and improve the quality of the user's experience.

[0004] In Non-Patent Document 1, implementation of XR in 5G NR (Fifth Generation New Radio), which is a wireless specification defined by the Third Generation Partnership Project (3GPP (registered trademark)), is being considered.

[0005] 3GPP TR 38.838 V17.0.0 (2021-12)3GPP TS 26.522 V0.1.0 (2023-05)

[0006] XR is operated under various requirements, including low latency. Therefore, XR proposes communication between a terminal device and a base station device while taking into account the relative relationships between multiple data. For example, Non-Patent Document 2 defines the Protocol Data Unit Set Importance (PSI). PSI is associated with a PDU set and represents its importance compared to other PDU sets within the same Quality of Service (QoS) flow. However, existing technical specifications (TS), including Non-Patent Document 2, do not specifically describe processes or procedures related to PSI. The inventors have discovered a problem: if the above-mentioned PSI-related processes or procedures are enabled or applied to a terminal device, the terminal device may not be able to properly perform the process. Note that the above problem also occurs in ordinary terminal devices and base station devices other than those implementing XR.

[0007] The present disclosure provides a technique that enables a terminal device to appropriately execute a process when a process or procedure related to PSI is enabled or applied to the terminal device.

[0008] A terminal device according to the present disclosure includes a control unit including a Packet Data Convergence Protocol (PDCP) entity and a receiving unit configured to receive, from a base station device, a Radio Resource Control (RRC) message including information for setting a first timer. The PDCP entity starts the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer. When the receiving unit receives an RRC message including information for setting a second timer and receives, using a Medium Access Control (MAC) control element (CE), information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled, the PDCP entity starts the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

[0009] Furthermore, the method of the terminal device in the present disclosure includes receiving, from a base station device, a Radio Resource Control (RRC) message including information for setting a first timer, and starting, in a Packet Data Convergence Protocol (PDCP) entity, the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer. The method further includes receiving an RRC message including information for setting a second timer, and, when information indicating enabling a Protocol Data Unit Set Importance (PSI)-based discard process is received using a Medium Access Control (MAC) Control Element (CE), starting, in the PDCP entity, the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

[0010] Furthermore, the base station apparatus in the present disclosure includes a transmitter, in a Packet Data Convergence Protocol (PDCP) entity of the terminal apparatus, configured to transmit to the terminal apparatus a Radio Resource Control (RRC) message including information for setting a first timer that is started based on reception of a PDCP service data unit (SDU) from a higher layer, the transmitter transmitting to the terminal apparatus an RRC message including information for setting a second timer, and transmitting to the terminal apparatus, using a Medium Access Control (MAC) Control Element (CE), information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled. When the RRC message including the information for setting the second timer is transmitted and information indicating that the PSI-based discard process is enabled is transmitted using the MAC CE, the second timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the upper layer.

[0011] According to the above configuration, when a process or procedure related to PSI is enabled or applied to a terminal device, the terminal device can appropriately execute the process. Note that the above configuration may provide other effects instead of or in addition to the above effect.

[0012] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a diagram illustrating a communication system S, Fig. 2 is a diagram illustrating a U-plane protocol stack, Fig. 3 is a diagram illustrating a C-plane protocol stack, Fig. 4 is a block diagram illustrating a schematic hardware configuration of a terminal device 10, Fig. 5 is a block diagram illustrating a schematic functional configuration of the terminal device 10, Fig. 6 is a block diagram illustrating a schematic hardware configuration of a base station device 20, Fig. 7 is a block diagram illustrating a schematic functional configuration of the base station device 20, and Fig. 8 is a block diagram illustrating a radio frame configuration. 9 is a diagram showing the configuration of a short BSR, FIG. 10 is a diagram showing the configuration of a long BSR, FIG. 11 is a sequence diagram showing the flow of processing by the terminal device 10 and the base station device 20, FIG. 12 is a diagram showing an example of the configuration of a long BSR including delay information, FIG. 13 is a diagram showing another example of the configuration of a long BSR including delay information, FIG. 14 is a diagram showing another example of the configuration of a long BSR including delay information, and FIG. 15 is a diagram for explaining an example of a first discard process among the PSI-based discard processes. 16 is a diagram for explaining another example of the first discarding process, FIG. 17 is a diagram for explaining another example of the first discarding process, FIG. 18 is a diagram for explaining an example of a second discarding process among the PSI-based discarding processes, FIG. 19 is a diagram for explaining another example of the second discarding process, FIG. 20 is a diagram for explaining a first aspect of the processing of the terminal device 10 when the first discarding process is enabled, and FIG. 21 is a diagram for explaining a second aspect of the processing of the terminal device 10 when the first discarding process is enabled. 22 is a diagram for explaining an example of triggering a delay information report using a first threshold value Th1 in a first mode, FIG. 23 is a diagram for explaining an example of triggering a delay information report using a first threshold value Th1 in a second mode, FIG. 24 is a sequence diagram showing the processing flow of the terminal device 10 and the base station device 20 according to the first embodiment, FIG. 25 is a diagram for explaining an example of triggering a delay information report using a second threshold value Th2 in the first mode, and FIG. 26 is a diagram for explaining an example of triggering a delay information report using a second threshold value Th2 in a first mode.FIG. 27 is a diagram for explaining an example of triggering a delay information report using a second threshold value Th2 in the second aspect, and FIG. 27 is a sequence diagram showing the flow of processing by the terminal device 10 and the base station device 20 according to the second embodiment.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, elements that can be similarly described will be designated by the same reference numerals, and redundant description may be omitted.

[0014] The embodiments described below are merely examples of configurations that can realize the present disclosure. Each of the following embodiments can be modified or changed as appropriate depending on the configuration of the device to which the present disclosure is applied and various conditions. Not all of the combinations of elements included in each of the following embodiments are necessarily essential for realizing the present disclosure, and some of the elements can be omitted as appropriate. Therefore, the scope of the present disclosure is not limited to the configurations described in each of the following embodiments. As long as there are no mutual contradictions, configurations that combine multiple configurations described in the following embodiments can also be adopted.

[0015] 1. Common Embodiments Hereinafter, configurations common to the first and second embodiments described below will be described.

[0016] 1, the communication system S includes one or more terminal apparatuses 10, one or more base station apparatuses 20, and a core network 30. The communication system S is configured according to predetermined technical specifications. For example, the communication system S may comply with technical specifications defined by 3GPP (e.g., 5G, 5G Advanced, 6G, etc.).

[0017] In the communication system S, a user plane where user data is transmitted and received and a control plane where control data is transmitted and received are configured separately. That is, the communication system S supports C / U separation. The user plane is abbreviated as U-plane, and the control plane is abbreviated as C-plane.

[0018] The terminal device 10 is a device that wirelessly communicates with the base station device 20 and may be, for example, user equipment (UE) that operates in accordance with the 3GPP 5G NR technical specifications. The terminal device 10 may also be a device that complies with other older or newer 3GPP technical specifications.

[0019] The terminal device 10 may be, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a laptop PC, a communication module, a communication card, or an IoT device such as a surveillance camera or a robot. The terminal device 10 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The terminal device 10 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The terminal device 10 may be a sensor or a device provided therein. Note that the terminal device 10 may be called by other names such as a terminal, a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit. The terminal device 10 may be a device adapted to one or more of enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC).

[0020] The base station device 20 manages at least one cell. A cell constitutes the smallest unit of a communication area. For example, one cell belongs to one frequency (e.g., carrier frequency) and is composed of one component carrier. The term "cell" can refer to wireless communication resources and can also refer to a communication target of the terminal device 10. The base station device 20 wirelessly communicates with the terminal device 10 located in its own cell in the U-plane and C-plane. In other words, the base station device 20 terminates the U-plane protocol and C-plane protocol for the terminal device 10.

[0021] The base station device 20 communicates with the core network 30 in the U-plane and the C-plane. More specifically, the core network 30 includes multiple logical nodes including an Access and Mobility Management Function (AMF) and a User Plane Function (UPF). The base station device 20 connects to the AMF in the C-plane and connects to the UPF in the U-plane.

[0022] The base station device 20 may be, for example, a gNB that provides the terminal device 10 with a U-plane and a C-plane conforming to the 3GPP 5G NR technical specifications and connects to the 3GPP 5GC (5G Core Network). The base station device 20 may also be a device conforming to other older or newer 3GPP technical specifications.

[0023] The base station device 20 may be configured by a plurality of unit devices. For example, the base station device 20 may be configured by a central unit (CU), a distributed unit (DU), and a radio unit (RU).

[0024] A radio access network (RAN) is formed by interconnecting multiple base station devices 20. The radio access network formed by the base station devices 20 that are gNBs may be referred to as an NG-RAN. The base station devices 20 that are gNBs may be referred to as NG-RAN nodes.

[0025] The plurality of base station devices 20 are connected to each other via a predetermined interface (for example, an Xn interface). More specifically, for example, the plurality of base station devices 20 are connected to each other via an Xn-U interface in the U-plane and via an Xn-C interface in the C-plane. Note that the plurality of base station devices 20 may also be connected to each other via other interfaces with different functions or names.

[0026] Each base station device 20 is connected to the core network 30 via a predetermined interface (for example, an NG interface). More specifically, for example, each base station device 20 is connected to the UPF of the core network 30 via an NG-U interface in the U-plane, and is connected to the AMF of the core network 30 via an NG-C interface in the C-plane. Note that each base station device 20 may be connected to the core network 30 via another interface with a different function or name.

[0027] The radio protocol architecture between the terminal device 10 and the base station device 20 will be described with reference to Fig. 2. The radio protocol architecture between the terminal device 10 and the base station device 20 and between the terminal device 10 and the core network 30 will be described with reference to Fig. 3.

[0028] As shown in Fig. 2, the U-plane protocol stack includes, from the bottom up, a physical (PHY) layer, a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer. Each of the above layers is terminated at the base station device 20 on the network side. The MAC layer is also referred to as a "medium access control layer."

[0029] As shown in FIG. 3 , the C-plane protocol stack includes, from the bottom up, a physical (PHY) layer, a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a non-access stratum (NAS). The MAC layer is also referred to as a "medium access control layer." The above-mentioned layers except for the non-access stratum are terminated at the base station device 20 on the network side. The non-access stratum is terminated at the AMF of the core network 30 on the network side.

[0030] 4, the terminal device 10 has, as hardware elements, a processor 101, a memory 102, an input / output interface 103, a wireless interface 104, and an antenna 105. The above elements provided in the terminal device 10 are connected to each other by an internal bus. Note that the terminal device 10 may have hardware elements other than the elements shown in FIG. 4.

[0031] The processor 101 is a computing element that realizes various functions of the terminal device 10. The processor 101 may be a system-on-a-chip (SoC) that includes elements such as a central processing unit (CPU), a graphics processing unit (GPU), and a memory controller.

[0032] The memory 102 is composed of at least one storage medium such as a RAM (Random Access Memory) or an eMMC (embedded Multi Media Card). The memory 102 is an element that temporarily or permanently stores programs and data used to execute various processes in the terminal device 10. The programs include one or more instructions for operating the terminal device 10. The processor 101 implements the functions of the terminal device 10 by expanding and executing the programs stored in the memory 102 in the memory 102 and / or a system memory (not shown).

[0033] The input / output interface 103 is an interface that receives operations on the terminal device 10 and supplies the operations to the processor 101, and presents various information to the user. The input / output interface 103 is, for example, a touch panel.

[0034] The wireless interface 104 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The wireless interface 104 transmits and receives wireless signals to and from the base station device 20 via an antenna 105.

[0035] 5, the terminal device 10 has, as functional blocks, a control unit 110 and a communication unit 120. The communication unit 120 has at least one transmission unit 121 and at least one reception unit 122.

[0036] The control unit 110 may include at least one processor 101 and at least one memory 102. In other words, the control unit 110 may be realized by the processor 101 and the memory 102. The control unit 110 executes various control processes in the terminal device 10. For example, the control unit 110 controls wireless communication with the base station device 20 via the communication unit 120. That is, the control unit 110 transmits and receives data / information / messages via the communication unit 120.

[0037] The communication unit 120 includes the wireless interface 104 and the antenna 105. In other words, the communication unit 120 is realized by the wireless interface 104 and the antenna 105. The communication unit 120 wirelessly communicates with the base station device 20 by transmitting and receiving wireless signals to and from the base station device 20. Two or more wireless interfaces 104 and two or more antennas 105 may be included in the communication unit 120.

[0038] The control unit 110 operates to execute various processes of the terminal device 10 .

[0039] 6, the base station device 20 has, as hardware elements, a processor 201, a memory 202, a network interface 203, a wireless interface 204, and an antenna 205. The above elements provided in the base station device 20 are connected to each other by an internal bus. Note that the base station device 20 may have hardware elements other than the elements shown in FIG. 6.

[0040] The processor 201 is a computing element that realizes various functions of the base station device 20. The processor 201 may be a CPU, and may further include other processors such as a GPU.

[0041] The memory 202 is configured by at least one storage medium such as a read-only memory (ROM), a RAM, a hard disk drive (HDD), or a solid state drive (SSD). The memory 202 is an element that temporarily or permanently stores programs and data used to execute various processes in the base station device 20. The programs include one or more instructions for operating the base station device 20. The processor 201 implements the functions of the base station device 20 by expanding and executing the programs stored in the memory 202 in the memory 202 and / or a system memory (not shown).

[0042] The network interface 203 is an interface used to transmit and receive signals to and from other base station devices 20 and the core network 30 .

[0043] The wireless interface 204 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The wireless interface 204 transmits and receives wireless signals to and from the terminal device 10 via an antenna 205.

[0044] 7, the base station device 20 has, as functional blocks, a control unit 210, a communication unit 220, and a network communication unit 230. The communication unit 220 has at least one transmission unit 221 and at least one reception unit 222.

[0045] The control unit 210 may include at least one processor 201 and at least one memory 202. In other words, the control unit 210 may be realized by the processor 201 and the memory 202. The control unit 210 executes various control processes in the base station device 20. For example, the control unit 210 controls wireless communication with the terminal device 10 via the communication unit 220. That is, the control unit 210 transmits and receives data / information / messages via the communication unit 220. Furthermore, for example, the control unit 210 controls communication with other nodes (e.g., other base station devices 20, nodes of the core network 30) via the network communication unit 230.

[0046] The communication unit 220 includes a wireless interface 204 and an antenna 205. In other words, the communication unit 220 is realized by the wireless interface 204 and the antenna 205. The communication unit 220 wirelessly communicates with the terminal device 10 by transmitting and receiving wireless signals to and from the terminal device 10. Two or more wireless interfaces 204 and two or more antennas 205 may be included in the communication unit 220.

[0047] The network communication unit 230 includes the network interface 203. In other words, the network communication unit 230 is realized by the network interface 203. The network interface 203 transmits and receives signals to and from the network (and thus to the other nodes described above).

[0048] The control unit 210 operates to execute various processes in the base station device 20 .

[0049] 1.2 Radio Resources The terminal device 10 and the base station device 20 communicate with each other wirelessly using radio resources in the frequency domain and the time domain. Radio resources will be described below.

[0050] The transmission method for downlink communication from the base station device 20 to the terminal device 10 is, for example, Orthogonal Frequency Division Multiplexing (OFDM) using a cyclic prefix (CP), i.e., CP-OFDM. The transmission method for uplink communication from the terminal device 10 to the base station device 20 is, for example, the above-mentioned CP-OFDM or DFTS-OFDM in which CP-OFDM is applied after transform precoding that performs discrete Fourier transform (DFT) spreading.

[0051] A cyclic prefix is ​​a redundant signal that functions as a guard period (GP) to prevent inter-symbol interference and inter-carrier interference, and is inserted at the beginning of an OFDM symbol. There are two types of cyclic prefixes: a normal cyclic prefix and an extended cyclic prefix.

[0052] As radio resources in the frequency domain of OFDM, multiple subcarriers that are orthogonal to each other are used. The multiple subcarriers are arranged in the frequency domain at a predetermined subcarrier spacing (sub-carrier spacing, SCS) Δf. Multiple subcarrier spacings Δf can be applied in a communication system S. The subcarrier spacing Δf can be expressed, for example, by the following equation: Δf=2 μ ・15 [kHz]

[0053] Here, μ is an integer equal to or greater than 0 and can take on at least one of the values ​​0, 1, 2, 3, 4, 5, and 6. Therefore, the subcarrier spacing Δf [kHz] can take on at least one of the values ​​15, 30, 60, 120, 240, 480, and 960. Note that μ may also take on a value of 7 or greater.

[0054] In the time domain of OFDM, a layered radio frame structure is used as shown in Figure 8. One radio frame includes 10 subframes. Subframes are assigned subframe numbers that count up by one from 0 to 9. One radio frame is divided into two half frames. The time length of a radio frame is 10 ms, the time length of a half frame is 5 ms, and the time length of a subframe is 1 ms. These time lengths do not depend on the subcarrier spacing Δf.

[0055] One subframe includes one or more slots (slot(s)). The number Ns of slots included in one subframe depends on the value of μ described above, and further depends on the subcarrier spacing Δf. The number Ns of slots is expressed by the following formula, for example: Ns=2 μ

[0056] One slot contains multiple symbols. The number of symbols in one slot depends on the type of cyclic prefix. For example, if a normal cyclic prefix is ​​used, one slot contains 14 symbols. For example, if an extended cyclic prefix is ​​used, one slot contains 12 symbols.

[0057] As described above, the number of slots and the number of symbols included in each of a radio frame, half frame, and subframe, each of which has a fixed time length, are variable. Therefore, the time length of a slot and the time length of a symbol are also variable.

[0058] A resource element (RE) is a radio resource unit in the time-frequency domain consisting of one subcarrier and one symbol, and a resource block (RB) is a radio resource unit in the time-frequency domain consisting of 12 subcarriers and multiple symbols.

[0059] Each radio frame is assigned a system frame number (SFN), which counts up by one from 0 to 1023. SFN "0" corresponds to the initial value of the SFN, and SFN "1023" corresponds to the maximum value of the SFN. Therefore, the radio frame following a radio frame assigned SFN 1023 is assigned SFN 0. Since the time length of a radio frame is 10 ms, the time length of one cycle of the system frame number is 10,240 ms (= 10.24 seconds).

[0060] Here, the base station device 20 may configure one or more serving cells for the terminal device 10. The serving cell may correspond to a component carrier in the downlink and / or a component carrier in the uplink. The technology in which one or more serving cells are configured and the base station device 20 and the terminal device 10 perform wireless communication may also be referred to as carrier aggregation.

[0061] Furthermore, the base station device 20 may configure one or more bandwidth parts (Bandwidth Parts, BWPs) for the terminal device 10 with respect to each of one or more serving cells. For example, a Downlink Bandwidth Part (DL-BWP) may be configured in the downlink of one serving cell. Furthermore, an Uplink Bandwidth Part (UL-BWP) may be configured in the uplink of one serving cell. Herein, the DL-BWP may include an initial DL-BWP and / or a dedicated DL-BWP. Furthermore, the UL-BWP may include an initial UL-BWP and / or a dedicated UL-BWP. Hereinafter, the BWP may include a DL-BWP and / or a UL-BWP.

[0062] 1.3 Channels and Control Information The terminal device 10 and the base station device 20 transmit and receive user data and control information to and from each other. The transmission and reception of control information in the downlink and uplink will be exemplified below.

[0063] The terminal device 10 and the base station device 20 transmit and receive user data and control information using a plurality of hierarchical channels. The physical channel is a channel used for physical communication between the terminal device 10 and the base station device 20. Examples of the physical channel include a physical downlink control channel (PDCCH), a physical broadcast channel (PBCH), and a physical uplink control channel (PUCCH).

[0064] A transport channel is a channel located above a physical channel and is mapped to a physical channel in the PHY layer. Multiple transport channels may be mapped to one physical channel. Examples of transport channels include a Downlink Shared Channel (DL-SCH) and an Uplink Shared Channel (UL-SCH). For example, data in the downlink may also be referred to as DL-SCH data. Furthermore, for example, data in the uplink may also be referred to as UL-SCH data. Here, DL-SCH data includes user data in the downlink. Furthermore, UL-SCH data includes user data in the uplink.

[0065] A logical channel is a channel located above a transport channel and is mapped to the transport channel in the MAC layer. Multiple logical channels may be mapped to one transport channel, and one logical channel may be mapped to multiple transport channels. Logical channels are classified according to the characteristics of the information they transmit. Examples of logical channels include a Broadcast Control Channel (BCCH), a Common Control Channel (CCCH), and a Dedicated Control Channel (DCCH).

[0066] The base station device 20 transmits downlink control information (DCI) to the terminal device 10 using the PDCCH, which is a physical channel. The DCI includes information on downlink and uplink resource allocation for the terminal device 10, and control information for the terminal device 10. The DCI is mapped to the PDCCH and corresponds to Layer 1 signaling.

[0067] Here, one or more formats may be defined for transmission of DCI in the PDCCH. The format defined for transmission of DCI in the PDCCH may be referred to as a DCI format. For example, the DCI format may include a DCI format used for scheduling a Physical Downlink Shared Channel (PDSCH) (e.g., a format referred to as DCI format 1_0, DCI format 1_1, and / or DCI format 1_2). Furthermore, for example, the DCI format may include a DCI format used for scheduling a Physical Uplink Shared Channel (PUSCH) (e.g., a format referred to as DCI format 0_0, DCI format 0_1, and / or DCI format 0_2). Furthermore, the DCI format may include a DCI format not used for scheduling a PDSCH and / or a PUSCH. The DCI format used for scheduling a PDSCH and / or a PUSCH may be referred to as a scheduling DCI format. A DCI format that is not used for scheduling the PDSCH and / or PUSCH may be referred to as a non-scheduling DCI format. Hereinafter, for ease of explanation, a "DCI format" may be simply referred to as a "PDCCH." Furthermore, a "DCI generated according to a DCI format" may be simply referred to as a "DCI format."

[0068] For example, the base station device 20 may configure frequency domain resources and / or time domain resources that the terminal device 10 monitors (i.e., monitors) a PDCCH candidate set. For example, the frequency domain resources that the terminal device 10 monitors the PDCCH candidate set may be referred to as a control resource set (CORESET). Furthermore, the time domain resources that the terminal device 10 monitors the PDCCH candidate set may be referred to as a search space set (SSS). The terminal device 10 may monitor the PDCCH candidate set in one or more CORESETs in the DL-BWP of a serving cell for which PDCCH monitoring is configured, according to the corresponding search space set. Here, monitoring may imply attempting to decode each PDCCH candidate according to the monitored DCI format. The above configuration may be referred to as blind decoding.

[0069] Here, a Cyclic Redundancy Check (CRC) scrambled with a Radio Network Temporary Identifier (RNTI) may be added to the DCI (or DCI format) transmitted on the PDCCH. The CRC may also be referred to as a CRC parity bit. Multiple types of RNTI are defined. For example, the base station device 20 may set each RNTI by transmitting an RRC message including at least one of information indicating a C-RNTI (Cell-RNTI), information indicating a Modulation and Coding Scheme Cell-RNTI (MCS-C-RNTI), and information indicating a Configured Scheduling-RNTI (CS-RNTI). That is, a CRC scrambled with at least one of the C-RNTI, MCS-C-RNTI, and CS-RNTI may be added to the DCI (or DCI format) transmitted on the PDCCH.

[0070] The terminal device 10 may monitor (and / or receive) the PDCCH and detect (and / or receive) the DCI format.

[0071] The terminal device 10 transmits uplink control information (UCI) to the base station device 20 using the PUCCH, which is a physical channel. The UCI includes control information such as a scheduling request (SR), a hybrid automatic repeat reQuest (HARQ) ACK / NACK, and channel state information (CSI). The UCI is mapped to the PUCCH or PUSCH and corresponds to layer 1 signaling.

[0072] The base station device 20 uses the DL-SCH, which is a transport channel, to transmit a control element (CE) of the MAC layer to the terminal device 10. The downlink MAC CE is mapped to the PDSCH via the DL-SCH and corresponds to Layer 2 signaling.

[0073] The terminal device 10 transmits a control element (CE) of the MAC layer to the base station device 20 using the UL-SCH, which is a transport channel. The uplink MAC CE includes control information such as a buffer status report (BSR). The uplink MAC CE is mapped to a PUSCH via the UL-SCH and corresponds to Layer 2 signaling.

[0074] The base station device 20 transmits (or broadcasts) system information (SI) to the terminal device 10 using the BCCH, which is a logical channel. The SI includes minimum system information (MSI) and other system information (OSI). The MSI includes a master information block (MIB) and system information block 1 (SIB1). SIB1 may be referred to as remaining minimum system information (RMSI). The OSI includes system information blocks (SIB2 onward) other than SIB1. Of the BCCH, the MIB is mapped to the PBCH via the BCH (Broadcast CHannel), and the SIB is mapped to the PDSCH via the DL-SCH.

[0075] The base station device 20 transmits control information in the RRC layer to the terminal device 10 using a signaling radio bearer (SRB) established between the terminal device 10 and the base station device 20 in the RRC layer. Hereinafter, messages exchanged between the base station device 20 and the terminal device 10 in the RRC layer may be referred to as RRC messages. There are multiple types of SRBs (e.g., SRB0, SRB1, SRB2, SRB3, SRB4). The SRBs are used to transmit and receive RRC messages as well as NAS messages containing control information in the NAS layer. The CCCH or DCCH is used to transmit RRC messages from the base station device 20 to the terminal device 10. The CCCH and DCCH are each mapped to the PDSCH via the DL-SCH. The RRC message corresponds to Layer 3 signaling.

[0076] As an example of a downlink RRC message, an RRC reconfiguration message will be described. The RRC reconfiguration message is an RRC message transmitted from the base station device 20 to the terminal device 10 using SRB1 or SRB3. The DCCH is used to transmit the RRC reconfiguration message. The RRC reconfiguration message is used to reconfigure or modify the connection between the base station device 20 and the terminal device 10.

[0077] The terminal device 10 transmits an RRC message to the base station device 20 using the above-mentioned SRB. The CCCH or DCCH is used to transmit the RRC message from the terminal device 10 to the base station device 20. The CCCH and DCCH are each mapped to the PUSCH via the UL-SCH. The RRC message corresponds to Layer 3 signaling.

[0078] As an example of an uplink RRC message, a user equipment capability information (UECapabilityInformation) message will be described. The user equipment capability information message is an RRC message transmitted from the terminal device 10 to the base station device 20 using SRB1. The DCCH is used to transmit the user equipment capability information message. The user equipment capability information message is used to notify the base station device 20 of information related to the radio access capability of the terminal device 10.

[0079] As an example of an uplink RRC message, a user equipment assistance information (UE Assistance Information, UAI) message will be described. The UAI message is an RRC message transmitted from the terminal device 10 to the base station device 20 using SRB1 or SRB3. The DCCH is used to transmit the UAI message. The UAI message is used to notify the base station device 20 of various information related to the terminal device 10 (e.g., UE assistance information).

[0080] 1.4. Uplink Scheduling 1.4.1. Scheduling Request (SR) The SR is used by the terminal device 10 to request PUSCH radio resource allocation from the base station device 20. The SR may also be used to request UL-SCH resources for initial transmission. The base station device 20 allocates PUCCH resources for transmitting the SR to the terminal device 10. The base station device 20 transmits an RRC message including SR parameters to the terminal device 10. The SR parameters are included in a SchedulingRequestResourceConfig IE, which is an example of an RRC information element (IE).

[0081] The terminal device 10 transmits UCI including SR to the base station device 20 using the configured PUCCH resource. The terminal device 10 may transmit UCI on demand. The terminal device 10 may transmit UCI at a configured periodicity. For example, the terminal device 10 may transmit an SR set to "0" (negative SR) and / or an SR set to "1" (positive SR). The base station device 20 allocates PUSCH radio resources to the terminal device 10 according to the SR.

[0082] 1.4.2 Dynamic Grant (DG) DG is a scheduling method for allocating PUSCH radio resources in accordance with an uplink grant procedure. The base station device 20 transmits an uplink grant to the terminal device 10 via the PDCCH. The terminal device 10 transmits the PUSCH in accordance with the uplink grant. For example, the base station device 20 may allocate PUSCH radio resources using a DCI format with a CRC scrambled by the C-RNTI and / or MCS-C-RNTI (i.e., a DCI format used for PUSCH scheduling), and the terminal device 10 may perform uplink transmission using the allocated PUSCH radio resources. Here, a new data indicator (New Data Indicator) included in the DCI format to which the CRC scrambled by the C-RNTI and / or MCS-C-RNTI is added may be set to 0 or 1. Furthermore, the base station device 20 may allocate radio resources for the PUSCH using a DCI format with a CRC scrambled by the CS-RNTI (i.e., a DCI format used for scheduling the PUSCH), and the terminal device 10 may perform uplink transmission using the allocated radio resources for the PUSCH. Here, a new data indicator included in the DCI format with a CRC scrambled by the CS-RNTI may be set to 1.

[0083] 1.4.3. Configured Grant (CG) CG is a scheduling method for allocating radio resources for the PUSCH without the above-described dynamic uplink grant procedure. CG includes two types: Type 1 and Type 2. The base station device 20 transmits an RRC message including CG parameters to the terminal device 10. The CG parameters are included in a ConfiguredGrantConfig IE, which is an example of an RRC information element (IE). The ConfiguredGrantConfig IE includes a parameter periodicity related to the periodicity of transmission using the PUSCH. Note that the parameter periodicity is set in units of the number of slots or the number of symbols. Alternatively, the parameter periodicity may be set in units of frames per second (FPS). In Type 1, the terminal device 10 starts transmitting signals at the set periodicity without being triggered by DCI. On the other hand, in Type 2, the base station device 20 transmits DCI scrambled with CS-RNTI to the terminal device 10. The CS-RNTI is used to activate periodic transmission. In response to activation by DCI scrambled with the CS-RNTI, the terminal device 10 starts transmission using the PUSCH at a set period.

[0084] 1.5 Buffer Status Report (BSR) The terminal device 10 transmits a BSR by MAC signaling using the allocated PUSCH radio resources. The BSR is composed of a MAC CE included in a MAC PDU (Medium Access Control Protocol Data Unit). The BSR indicates information about the buffer status of uplink data of the MAC entity. The base station device 20 allocates uplink radio resources to the terminal device 10 based on the BSR.

[0085] In the BSR, logical channels (LCHs) are assigned to logical channel groups (LCGs). Each LCG includes one or more logical channels. The terminal device 10 calculates the buffer size of uplink data for each LCG. The terminal device 10 transmits the buffer size corresponding to each LCG as a BSR to the base station device 20.

[0086] The base station device 20 transmits an RRC message including BSR parameters to the terminal device 10. The BSR parameters are included in a BSR-Config IE, which is an example of an RRC information element (IE). For example, the BSR-Config IE includes three timers: a periodicBSR-Timer, a retxBSR-Timer, and a logicalChannelSR-DelayTimer.

[0087] Furthermore, parameters related to the LCG are included in the LogicalChannelConfig IE, which is an example of an RRC information element (IE). That is, the base station device 20 may transmit an RRC message including the LogicalChannelConfig IE. Furthermore, the terminal device 10 may identify settings related to the logical channels and / or the LCG based on the LogicalChannelConfig IE included in the RRC message. For example, the LogicalChannelConfig IE includes a logicalChannelGroup IE. The logicalChannelGroup IE assigns logical channels to an LCG. For example, an LCG index (ID) may be set for each of one or more logical channels, and the LCG to which the one or more logical channels belong may be set. Note that the LogicalChannelConfig IE may include a logicalChannelGroupIAB-Ext IE. The logicalChannelGroupIAB-Ext IE is applied only to IAB-MT (Integrated Access Backhaul-Mobile Termination). If the logicalChannelGroupIAB-Ext IE is set, the LogicalChannelConfig IE is ignored.

[0088] The terminal device 10 may trigger a BSR according to a predetermined condition. For example, the terminal device 10 may trigger a BSR when any of the following conditions (a1) to (a4) is satisfied for an activated cell group. Note that the following conditions may be referred to as "events." (a1) For a logical channel belonging to a certain LCG, uplink data becomes available in the MAC entity, and one of the following two conditions is satisfied: - The uplink data belongs to a logical channel with a higher priority than a logical channel belonging to any LCG that contains available uplink data. - There is no logical channel belonging to any LCG that contains available uplink data. (a2) Uplink resources are allocated, and the number of padding bits is equal to or greater than the size of the BSR MAC CE plus its subheader. (a3) ​​The retxBSR-Timer expires, and at least one logical channel belonging to the LCG contains uplink data. (a4) The periodic BSR-Timer expires.

[0089] The BSR includes at least a Regular BSR, a Padding BSR, and a Periodic BSR. The Regular BSR, the Padding BSR, and the Periodic BSR may be triggered based on different conditions. For example, the terminal device 10 triggers a Regular BSR when any of the above conditions (a1) and (a3) ​​is satisfied. The terminal device 10 triggers a Padding BSR when the above condition (a2) is satisfied. The terminal device 10 triggers a Periodic BSR when the above condition (a4) is satisfied.

[0090] The BSR includes multiple formats, including at least a short BSR and a long BSR. A MAC PDU including a BSR includes a MAC subheader. The MAC subheader includes a Logical Channel Identifier (LCID) or an extended Logical Channel Identifier (eLCID). The value of the LCID or eLCID may be referred to as a codepoint. The codepoint value identifies the short BSR and the long BSR.

[0091] The short BSR is a format for reporting the buffer status (i.e., buffer size) of one LCG. As shown in Figure 9, the short BSR includes one field 900 with a fixed size of 8 bits. The field 900 includes a first part 910 and a second part 920.

[0092] The first part 910 is made up of three bits. The first part 910 is information for identifying the LCG for which the buffer status is reported. The first part 910 is sometimes referred to as an "LCG ID field."

[0093] The second part 920 consists of 5 bits. The second part 920 is information for identifying the total amount of data available in all logical channels included in the LCG indicated by the first part 910. The second part 920 may also be simply referred to as the "buffer size." The second part 920 indicates an index indicating the number of bytes. For example, the second part 920 indicates any value from 0 to 31.

[0094] The short BSR may include a Truncated format, which is a format for a logical channel with a high priority (i.e., LCH priority), and an Extended format, which is a format capable of transmitting a larger amount of information.

[0095] The Long BSR is a format for reporting the buffer status (i.e., buffer size) of multiple LCGs. As shown in Figure 10, the Long BSR has a variable size. The Long BSR includes an LCG field 1010 and a buffer size field 1020.

[0096] The LCG field 1010 is composed of 8 bits. In the LCG field 1010, the 8 bits correspond to 8 LCGi, respectively. Here, i is an integer from 0 to 7. The definition of i will remain the same in the following description. The LCG field 1010 may indicate whether a buffer size field for LCGi exists. For example, if the value of LCGi in the LCG field 1010 is 1, this indicates that a buffer size field corresponding to LCGi exists. If the value of LCGi is 0, this indicates that a buffer size field corresponding to LCGi does not exist.

[0097] The number of fields included in the buffer size field 1020 varies depending on the value of the LCG field 1010. In the example of Fig. 10 , it is assumed that the bit corresponding to LCG1 and the bit corresponding to LCG2 in the LCG field 1010 are 1. Therefore, the buffer size field 1020 includes a field 1021 corresponding to LCG1 and a field 1022 corresponding to LCG2. Note that, since it is assumed that the bit corresponding to LCG0 in Fig. 10 is 0, the buffer size field 1020 does not include a field corresponding to LCG0.

[0098] Each field included in the buffer size field 1020 is made up of 8 bits. Each field indicates an index that indicates the number of bytes. For example, each field indicates one of values ​​from 0 to 254.

[0099] Like the short BSR, the long BSR may include a truncated format and an extended format.

[0100] The BSR may also include a Pre-emptive BSR format and an Extended Pre-emptive BSR format, which are used in the IAB-MT.

[0101] The terminal device 10 may select either a short BSR or a long BSR according to a predetermined method. For example, in the case of a regular BSR and a periodic BSR, the terminal device 10 may select either a short BSR or a long BSR as follows: When a MAC PDU including a BSR is constructed, if two or more LCGs have available data for transmission, the terminal device 10 transmits long BSRs for all LCGs that have available data. Otherwise, the terminal device 10 transmits short BSRs.

[0102] In the case of regular BSR and periodic BSR, for a MAC entity in which the logicalChannelGroup-IABExt IE is configured by a higher layer, the terminal device 10 may select either a short BSR or a long BSR as follows: If two or more LCGs have available data for transmission and the maximum value of LCG IDs among the configured LCGs is 7 or less, the terminal device 10 transmits a long BSR for all LCGs with available data. If two or more LCGs have available data for transmission and the maximum value of LCG IDs among the configured LCGs is greater than 7, the terminal device 10 transmits an extended long BSR for all LCGs with available data. If one or more LCGs have available data for transmission, the terminal device 10 transmits an extended short BSR.

[0103] In addition, in the case of a padding BSR, the terminal device 10 may transmit one of the following BSR formats according to the conditions that are met: Short BSR Long BSR Short Truncated BSR Long Truncated BSR Extended Short Truncated BSR Extended Long Truncated BSR

[0104] 1.6 Data Discard Processing The transmitting PDCP entity maintains a PDCP discard timer. Hereinafter, this PDCP discard timer is referred to as the "first timer Tm1." For example, the terminal device 10 uses the first timer Tm1 to perform data discard processing. The first timer Tm1 is set for a data radio bearer (DRB).

[0105] The base station device 20 transmits an RRC message including an IE related to PDCP to the terminal device 10. The duration of the first timer Tm1 may be included in a PDCP-config IE, which is an example of an IE related to PDCP.

[0106] The PDCP entity of the terminal device 10 maintains a first timer Tm1. The PDCP entity receives a PDCP SDU (Service Data Unit) from an upper layer. Upon receiving the PDCP SDU, the PDCP entity starts a first timer Tm1 associated with the PDCP SDU.

[0107] When the first timer Tm1 expires for a PDCP SDU, the PDCP entity discards the PDCP SDU together with the corresponding PDCP data PDU, and if the corresponding PDCP data PDU has already been transmitted to a lower layer, the PDCP entity instructs the lower layer to discard the PDCP data PDU.

[0108] 1.7 Extended Reality (XR) This section describes the characteristics of traffic generated in XR. In XR, multiple types of data (video data, audio data, user data, control data, etc.) are transmitted and received in parallel. The multiple data streams corresponding to the above data each have different traffic characteristics and QoS requirements.

[0109] The timing of sending and receiving the above data can sometimes experience time shifts, which can be expressed as jitter, variability, or fluctuation, due to factors such as video and audio encoding and network delays.

[0110] Reference 1 states that the following definitions may be introduced for transmission and reception in XR: [Reference 1] 3GPP TR 23.700-60 V1.1.0 (2022-09)

[0111] PDU Set: A set of PDUs consisting of one or more PDUs that carry the payload of one unit of information generated at the application level. The application level corresponds, for example, to a frame or a video slice in an XR service. Data Burst: A set of data multiple PDUs generated and transmitted by an application in a short period of time.

[0112] Furthermore, in XR, the packet delay budget (PDB) requirement is considered as one of the above QoS requirements. PDB is the upper bound of the allowable packet delay time between the terminal device 10 and the UPF. Reference 1 also describes that the following new QoS parameters may be introduced: PDU-Set Delay Budget (PSDB): This is the upper bound of the allowable PDU set delay time between the terminal device 10 and the UPF. PDU-Set Error Rate (PSER): This is the upper bound of the error rate calculated between a PDU set processed by the sender and all PDUs in the PDU set that are not successfully delivered to the upper layer of the corresponding receiver.

[0113] 1.8. Delay Information Report 1.8.1 Basic Configuration of Delay Information Report It is expected that XR will be operated under various requirements, including a requirement for low latency. Accordingly, for uplink communication from the terminal device 10, the base station device 20 allocates radio resources taking into consideration the above requirements. To allocate such radio resources, the terminal device 10 transmits a delay information report including delay information for predetermined data to the base station device 20. Note that the delay information report may also be referred to as a "delay status report."

[0114] The above-mentioned predetermined data means a unit of data to be reported in a delay information report. Hereinafter, the above-mentioned predetermined data may be referred to as "data to be reported" or "unit of data to be reported." According to this configuration, the terminal device 10 can transmit delay information about the data to be reported to the base station device 20.

[0115] The unit of data to be reported may be data corresponding to one LCG, which may include one or more LCHs (i.e., data corresponding to one or more LCHs). In this configuration, the unit of data to be reported may be some or all of the data available for one LCG.

[0116] The unit of data to be reported may be data corresponding to one PDU. In this configuration, the unit of data to be reported may be a part or all of the data available for one PDU. Also, the unit of data to be reported may be data corresponding to one PDU set. In this configuration, the unit of data to be reported may be a part or all of the data available for one PDU set. Furthermore, the unit of data to be reported may be data corresponding to multiple PDU sets. For example, the unit of data to be reported may be data (or a part of data) available for one, several, or all PDUs (or PDU sets) belonging to one PDU set.

[0117] The unit of data to be reported may be data corresponding to one data burst. In this configuration, the unit of data to be reported may be a portion or all of the data available for one data burst. Note that the unit of data to be reported may be data corresponding to multiple data bursts. For example, the unit of data to be reported may be data (or a portion of data) available for one, multiple, or all of the data (or data bursts) belonging to one data burst.

[0118] The delay information may include one or both of information that explicitly indicates a delay and information that implicitly indicates a delay.

[0119] - Information explicitly indicating a delay For example, the delay information may be a delay time or an index representing a delay time. The delay information may be the remaining time until a predetermined first deadline is reached. The remaining time may be calculated based on the first timer (i.e., the PDCP discard timer) Tm1. The terminal device 10 may calculate the remaining time based on the first timer Tm1, taking the time of the initial (or first) transmission of the delay information report as a reference. For example, the terminal device 10 may calculate the remaining time of a PDU in a certain PDU set based on the first timer Tm1 associated with the first arriving PDU in the PDU set. The delay information may include information about multiple remaining times. In another example, the delay information may be information about the shortest remaining time among multiple remaining times.

[0120] - Information implicitly indicating delay For example, the delay information may include information about data to which a time constraint or requirement is imposed among the data to be reported. Hereinafter, the entire data to be reported will be referred to as "first data", and the data to which a time constraint or requirement is imposed among the data to be reported will be referred to as "second data". The delay information may be information about the size of the second data. For example, the delay information may be an index indicating the number of bytes of the second data.

[0121] The second data is data that should be transmitted with priority. The second data may be referred to as urgent data. The second data may be data that satisfies a delay condition. For example, the second data may be data associated with the remaining time. For example, a predetermined first threshold Th1 may be applied to the remaining time of the first timer Tm1. The second data may be data whose remaining time is less than the first threshold Th1.

[0122] In another example, the second data may be data that has a constraint or requirement regarding time-varying delay such as jitter, etc. In yet another example, the second data may be data that has a transmission rate constraint or requirement.

[0123] For example, the base station device 20 may transmit information indicating the first threshold value Th1 to the terminal device 10. The base station device 20 may transmit an RRC message including information indicating the first threshold value Th1 to the terminal device 10. The first threshold value Th1 may be set for the LCH. For example, the first threshold value Th1 may be set as a new element of the LogicalChannelConfig IE. The first threshold value Th1 may be set for the LCG. For example, the first threshold value Th1 may be set as a new element of the LogicalChannelGroup IE. The first threshold value Th1 may be set for a PDU or a PDU set. The first threshold value Th1 may be set for an IE related to a PDU or a PDU set included in an RRC message. The first threshold value Th1 may be set for a data burst. The first threshold value Th1 may be set for an IE related to a data burst included in an RRC message. The first threshold value Th1 may be set for the terminal device 10. The base station device 20 may transmit system information (SI, for example, SIB1 and / or an SIB other than SIB1) including information indicating the first threshold value Th1 to the terminal device 10. The base station device 20 may transmit DCI including information indicating the first threshold value Th1 to the terminal device 10.

[0124] The base station device 20 may set multiple first thresholds Th1 for each LCG. In this configuration, the multiple first thresholds Th1 may be different from each other. Similarly, the base station device 20 may set multiple first thresholds Th1 for each PDU, PDU set, or data burst.

[0125] The first threshold Th1 may be used as a threshold for triggering a delay information report. That is, the terminal device 10 may trigger (and / or transmit) a delay information report based on the first threshold Th1. When the remaining time falls below the first threshold Th1, the terminal device 10 may trigger (and / or transmit) a delay information report. For example, when the remaining time for a certain PDU or PDU set falls below the first threshold Th1 set for the LCG, the terminal device 10 may trigger (and / or transmit) a delay information report.

[0126] The base station device 20 may determine the degree of delay based on the delay information included in the delay information report. For example, the base station device 20 may determine the degree of delay based on the remaining time and / or the size of the second data. Furthermore, the base station device 20 may allocate radio resources for uplink communication from the terminal device 10 based on the delay information.

[0127] 1.8.2 Specific Configuration of Delay Information Report The terminal device 10 may transmit a MAC CE including delay information as a delay information report. For example, the terminal device 10 may transmit a BSR including a delay information report. In this configuration, the terminal device 10 may transmit a BSR including a delay information report according to the following procedure.

[0128] As shown in FIG. 11 , the communication unit 220 of the base station device 20 transmits an RRC message to the terminal device 10 (S1101). The RRC message includes parameters related to a BSR. The RRC message may be an RRC Reconfiguration message. The control unit 110 of the terminal device 10 generates a BSR based on the parameters included in the RRC message. The BSR includes buffer size information related to the buffer size and delay information. The communication unit 120 of the terminal device 10 transmits a BSR including a delay information report (S1102). The control unit 210 of the base station device 20 allocates radio resources to the terminal device 10 based on the delay information report.

[0129] When the delay information report is included in the BSR, the terminal device 10 may trigger the BSR including the delay information report based on at least one of the above conditions (a1) to (a4). Furthermore, as described above, the terminal device 10 may trigger the BSR including the delay information report based on the first threshold value Th1. When the remaining time falls below the first threshold value Th1, the terminal device 10 may trigger the BSR including the delay information report.

[0130] The terminal device 10 may transmit a long BSR 1200 shown in FIG. 12. The long BSR 1200 includes a first field 1210 and a second field 1220.

[0131] The first field 1210 may have the same configuration as the LCG field 1010 in FIG. 10 . The first field 1210 may also be a field indicating whether LCGi has available data. For example, if the value of LCGi in the first field 1210 is 1, this may indicate that LCGi has available data. If the value of LCGi is 0, this may indicate that LCGi does not have available data. The first field 1210 may also be a field indicating whether LCGi has available second data. For example, the first field 1210 may be a field indicating whether LCGi has available data such that the remaining time of a first timer Tm1 is less than a first threshold Th1.

[0132] In this example, the second field 1220 includes three fields 1221-1223.

[0133] Field 1221 is a field related to LCG1. Field 1221 includes a first portion 1221a and a second portion 1221b. In this example, first portion 1221a is composed of 6 bits, and second portion 1221b is composed of 2 bits. However, this configuration is not limited thereto, and first portion 1221a and second portion 1221b may each be composed of a different number of bits from this example.

[0134] The first portion 1221a represents the buffer size for the data corresponding to LCG1. For example, the first portion 1221a may be an index indicating the number of bytes. The control unit 110 may refer to a 6-bit first buffer size table to set the index in the first portion 1221a. The first buffer size table is a table that defines the correspondence between the buffer size and the index.

[0135] The second portion 1221b represents delay information (e.g., the remaining time) related to the data corresponding to LCG1. The second portion 1221b may be an index representing the delay information. The control unit 110 may refer to a 2-bit delay information table to set the index in the second portion 1221b. The delay information table is a table that defines the correspondence between delay information and an index.

[0136] Field 1222 is a field related to LCG2. Field 1222 includes a first portion 1222a and a second portion 1222b. The configurations of first portion 1222a and second portion 1222b are the same as those of first portion 1221a and second portion 1221b described above.

[0137] Field 1223 is a field related to LCG3. Field 1223 indicates the buffer size related to the data corresponding to LCG3. Assume that the remaining time for the data corresponding to LCG3 is greater than the first threshold Th1. That is, the data corresponding to LCG3 is not delayed. In this case, field 1223 may include information related to the buffer size but not delay information. The control unit 110 may refer to a second 8-bit buffer size table to set an index in field 1223. The second buffer size table defines the correspondence between buffer sizes and indexes. In this way, the control unit 110 may switch between the first buffer size table and the second buffer size table to set an index corresponding to information related to the buffer size.

[0138] In the above example, the second field 1220 includes three fields 1221 to 1223, but is not limited to this configuration. The number of fields included in the second field 1220 may be variable. In another example, the order of the fields included in the second field 1220 may be determined based on LCH priority.

[0139] In another example, the Long BSR 1200 may include a third field indicating whether to include delay information for each LCG. For example, in the third field, if the value of LCGi is 1, this may indicate that delay information for LCGi is included. If the value of LCGi is 0, this may indicate that delay information for LCGi is not included.

[0140] In yet another example, the first portion 1221a of field 1221 and the first portion 1222a of field 1222 may each contain information regarding the size of the second data. The second data may be data for which the remaining time is below the first threshold Th1. For example, the first portion 1221a of field 1221 may contain information regarding the size of the second data corresponding to LCG1. Similarly, the first portion 1222a of field 1222 may contain information regarding the size of the second data corresponding to LCG2. Also, in this example, the second portion 1221b of field 1221 may not be included in field 1221, and the second portion 1222b of field 1222 may not be included in field 1222.

[0141] As shown in Fig. 13, each of fields 1221 to 1223 included in second field 1220 may include a first portion corresponding to information related to buffer size and a second portion corresponding to delay information. In the following, only the portions different from the configuration in Fig. 12 will be described, and a description of the portions that are the same as the configuration in Fig. 12 will be omitted.

[0142] Field 1223 is a field related to LCG3. Field 1223 includes a first portion 1223a and a second portion 1223b. In this example, first portion 1223a is composed of 6 bits, and second portion 1223b is composed of 2 bits. For example, first portion 1223a may be an index indicating the number of bytes. The control unit 110 may refer to the first buffer size table to set the index in first portion 1223a. As described above, it is assumed that the remaining time for data corresponding to LCG3 is greater than the first threshold value Th1. In this case, second portion 1223b may be blank. In another example, second portion 1223b may be a value (or index) indicating that delay information is not reported.

[0143] Furthermore, the configuration of the second field 1220 is not limited to the above example. As shown in Fig. 14, the second field 1220 may include an 8-bit field 1410 corresponding to information about the buffer size and an 8-bit field 1420 corresponding to delay information. For example, the field 1410 represents information about the buffer size of data corresponding to LCG1, and the field 1420 represents delay information about the data corresponding to LCG1. In this way, the buffer size information and delay information about one LCG may be represented by two different fields.

[0144] Although the configuration of the long BSR has been described in the above example, the present invention is not limited to this example. The above configuration may also be applied to a short BSR. For example, the terminal device 10 may transmit a short BSR including delay information.

[0145] Although the configuration of the BSR including the delay information report has been described, the present invention is not limited to this configuration. A new MAC CE for transmitting delay information may be defined. For example, the terminal device 10 may transmit a MAC CE including delay information as a delay information report. Therefore, the "BSR including delay information" described in this specification may be replaced with a "MAC CE including delay information."

[0146] The terminal device 10 may receive first instruction information related to the delay information report from the base station device 20. The base station device 20 may transmit an RRC message including the first instruction information to the terminal device 10. The base station device 20 may transmit system information (SI, for example, SIB1 and / or an SIB other than SIB1) including the first instruction information to the terminal device 10. The base station device 20 may transmit DCI including the first instruction information to the terminal device 10.

[0147] The first instruction information may be "information indicating whether to trigger (or transmit) a delay information report." The first instruction information may indicate "to trigger (or transmit) a delay information report" or "not to trigger (or transmit) a delay information report." The first instruction information may be a flag indicating "to trigger (or transmit) a delay information report" or "not to trigger (or transmit) a delay information report." Note that the first instruction information may be "information indicating whether to transmit delay information (e.g., the remaining time described above)." Furthermore, the first instruction information may be "information indicating whether to transmit information regarding the size of the second data."

[0148] For example, the terminal device 10 may trigger (or transmit) a delay information report when the RRC message includes first instruction information. Furthermore, the terminal device 10 may not trigger (or transmit) a delay information report when the RRC message does not include first instruction information.

[0149] The first instruction information may be set for an LCG. The terminal device 10 may determine whether to include delay information for the LCG in the BSR based on the first instruction information set for the LCG. For example, if the first instruction information indicates that delay information is to be transmitted for a certain LCG, the terminal device 10 may include the delay information for the LCG in the BSR. For example, the first instruction information may be set as a new element of the logicalChannelGroup IE. The first instruction information may be set for an LCH. For example, the first instruction information may be set as a new element of the LogicalChannelConfig IE. The terminal device 10 may determine whether to include delay information for the LCH in the BSR based on the first instruction information set for the LCH. For example, if the first instruction information indicates that delay information is to be transmitted for a certain LCH, the terminal device 10 may include the delay information for the LCH in the BSR. The first instruction information may be set for a PDU or a PDU set. The terminal device 10 may determine whether to include delay information for a PDU or a PDU set in the BSR based on first instruction information set for the PDU or PDU set. For example, if the first instruction information indicates that delay information is to be transmitted for a certain PDU or PDU set, the terminal device 10 may include the delay information for the certain PDU or PDU set in the BSR. The first instruction information may be set in an IE associated with a PDU or PDU set included in the RRC message. The first instruction information may be set for a data burst. The terminal device 10 may determine whether to include delay information for the certain data burst in the BSR based on the first instruction information set for the data burst. For example, if the first instruction information indicates that delay information is to be transmitted for a certain data burst, the terminal device 10 may include the delay information for the certain data burst in the BSR. The first instruction information may be set in an IE associated with a data burst included in the RRC message.

[0150] The base station device 20 may use the first threshold Th1 to indicate to the terminal device 10 whether to trigger (or transmit) a delay information report. For example, the terminal device 10 may control to trigger (and / or transmit) a delay information report when the RRC message includes information indicating the first threshold Th1. That is, when the RRC message includes information indicating the first threshold Th1, the terminal device 10 may include a delay information report in the BSR based on the first threshold Th1. Furthermore, the terminal device 10 may control not to trigger (and / or transmit) a delay information report when the RRC message does not include information indicating the first threshold Th1. That is, when the RRC message does not include information indicating the first threshold Th1, the terminal device 10 may not include a delay information report in the BSR.

[0151] The terminal device 10 may receive second instruction information related to the delay information report from the base station device 20. The base station device 20 may transmit an RRC message including the second instruction information to the terminal device 10. The base station device 20 may transmit system information (SI, for example, SIB1 and / or an SIB other than SIB1) including the second instruction information to the terminal device 10. The base station device 20 may transmit DCI including the second instruction information to the terminal device 10.

[0152] The second instruction information may indicate a type of data to be reported. For example, the second instruction information may be information indicating any one of an LCH, an LCG, a PDU, a PDU set, and a data burst. In this configuration, the terminal device 10 may select a type of data to be reported based on the second instruction information. The terminal device 10 may transmit a delay information report for the selected data.

[0153] The second indication information may be information implicitly indicated according to an IE to which the first indication information is set. For example, if the first indication information is set for a MAC cell group, this may indicate that the unit of data to be reported is data corresponding to one LCG. For example, the first indication information may be set in an IE related to a MAC cell group included in the RRC message. An example of such an IE is a BSR-config IE. As another example, if the first indication information is set for an LCG, this may indicate that the unit of data to be reported is data corresponding to one LCG. For example, the first indication information may be set in an IE related to an LCG. An example of such an IE is a logicalChannelGroup IE. If the first indication information is set for an LCH, this may indicate that the unit of data to be reported is data corresponding to one LCH. The first indication information may be set in an IE related to an LCH. An example of such an IE is a LogicalChannelConfig IE.

[0154] If the first indication information is set for a PDU or a PDU set, it may indicate that the data unit to be reported is data corresponding to a PDU or one or more PDU sets, for example, the first indication information may be set in an IE related to a PDU or a PDU set included in the RRC message.

[0155] If the first indication information is set for a data burst, it may indicate that the unit of data to be reported is data corresponding to one or more data bursts. For example, the first indication information may be set in an IE related to a data burst included in the RRC message.

[0156] The MAC PDU may include identification information for identifying whether it is a delay information report. For example, the MAC subheader includes an LCID or eLCID value (i.e., a code point). An LCID or eLCID value indicating a delay information report may be defined. The following LCID or eLCID values ​​may be defined based on the type of data to be reported: - The MAC CE includes a delay information report, and the unit of the data to be reported is data corresponding to one LCH. - The MAC CE includes a delay information report, and the unit of the data to be reported is data corresponding to one LCG. - The MAC CE includes a delay information report, and the unit of the data to be reported is data corresponding to one PDU. - The MAC CE includes a delay information report, and the unit of the data to be reported is data corresponding to one or more PDU sets. - The MAC CE includes a delay information report, and the unit of the data to be reported is data corresponding to one or more data bursts.

[0157] When the BSR includes a delay information report, the following LCID or eLCID values ​​may be defined based on the type of data to be reported: - The BSR includes a delay information report, and the unit of the data to be reported is data corresponding to one LCH. - The BSR includes a delay information report, and the unit of the data to be reported is data corresponding to one LCG. - The BSR includes a delay information report, and the unit of the data to be reported is data corresponding to one PDU. - The BSR includes a delay information report, and the unit of the data to be reported is data corresponding to one or more PDU sets. - The BSR includes a delay information report, and the unit of the data to be reported is data corresponding to one or more data bursts.

[0158] Additionally, a value of LCID or eLCID may be defined that indicates whether the BSR contains a delay information report and is in one of the following formats: Short BSR, Long BSR, Short Truncated BSR, Long Truncated BSR, Extended Short Truncated BSR, Extended Long Truncated BSR, Pre-emptive BSR, Extended Pre-emptive BSR.

[0159] In another example, the MAC CE including the delay information report may include the above-mentioned identification information. For example, the BSR may further include a field including identification information indicating that the BSR includes delay information.

[0160] 1.9 PDU Set Importance (PSI) In communications requiring real-time performance such as XR, the Real-time Transport Protocol (RTP) is assumed to be used. An RTP packet includes an RTP payload and an RTP header.

[0161] Non-Patent Document 2 defines fields included in the RTP Header Extension. The importance of the PDU set (i.e., PSI) is included in the RTP Header Extension. The PSI is associated with a PDU set and indicates its importance compared to other PDU sets within the same QoS flow.

[0162] The PSI is represented by, for example, 4 bits. The PSI may have a value between 0 and 15. The lower the PSI value, the higher the importance of the PDU set associated with that PSI. For example, a PDU set associated with a PSI of "0" has the highest importance. A PDU set associated with a PSI of "15" has the lowest importance. Therefore, in the following description, the expression "a relatively small PSI value" may be rephrased as "the importance of the corresponding data (i.e., PDU set) is relatively high." The expression "a relatively large PSI value" may be rephrased as "the importance of the corresponding data (i.e., PDU set) is relatively low."

[0163] 1.10. Data Discard Processing Based on PSI When congestion occurs, the terminal device 10 may perform data discard processing based on PSI. Hereinafter, for ease of notation, such discard processing is also referred to as "PSI-based discard processing."

[0164] The terminal device 10 may receive first configuration information related to the PSI-based discard process from the base station device 20. The first configuration information may be information indicating that the PSI-based discard process is to be activated or applied. The first configuration information may be information indicating that congestion has occurred. For example, the base station device 20 may transmit the first configuration information to the terminal device 10 using a PDCP control PDU, an RRC message, a MAC CE, or a DCI. When receiving the first configuration information from the base station device 20, the terminal device 10 may activate the PSI-based discard process.

[0165] The terminal device 10 may receive second configuration information related to the PSI-based discard process from the base station device 20. The second configuration information may be information indicating that the PSI-based discard process is to be deactivated or not applied. The second configuration information may be information indicating that congestion has been resolved. For example, the base station device 20 may transmit the second configuration information to the terminal device 10 using a PDCP control PDU, an RRC message, a MAC CE, or a DCI. When receiving the second configuration information from the base station device 20, the terminal device 10 may disable the PSI-based discard process.

[0166] In another example, the terminal device 10 may receive, instead of the second setting information, period information regarding a period during which the PSI-based discard process is enabled from the base station device 20. In this configuration, the terminal device 10 may enable the PSI-based discard process from the time point at which the terminal device 10 receives the first setting information until the period indicated by the period information has elapsed. The terminal device 10 may receive, from the base station device 20, an RRC message including the period information. In another example, the period information may be included in the first setting information.

[0167] In another example, the terminal device 10 may enable PSI-based discard processing until there is no data held (or buffered) in the associated DRB.

[0168] The state in which the PSI-based discard process is not enabled may be referred to as a "first state," a "normal state," a "first mode," etc. The state in which the PSI-based discard process is enabled may be referred to as a "second state," a "congestion state," a "second mode," etc.

[0169] The PSI-based discard process may include at least one of a first discard process and a second discard process described below.

[0170] 1.10.1 First Discard Process The PDCP entity of the terminal device 10 may execute the first discard process using one or more PDCP discard timers different from the above-described first timer Tm1. Hereinafter, the discard timer used in the first discard process will be referred to as the "second timer Tm2" to distinguish it from the first timer Tm1.

[0171] A second timer Tm2 may be set for the DRB. As shown in Fig. 15 , the PDCP entity of the terminal device 10 receives a packet 1501 from an upper layer at time t0. The terminal device 10 starts a first timer Tm1 from time t0. When the first timer Tm1 expires, the terminal device 10 discards the packet 1501.

[0172] At time t1, the terminal device 10 receives first setting information from the base station device 20. The terminal device 10 enables the first discard process based on the first setting information. That is, the terminal device 10 switches the discard timer it uses from the first timer Tm1 to the second timer Tm2. In this example, the terminal device 10 keeps the first discard process enabled until it receives second setting information from the base station device 20.

[0173] Thereafter, the PDCP entity of the terminal device 10 receives packet 1502 from the upper layer at time t2. The terminal device 10 starts a second timer Tm2 from time t2. The second timer Tm2 may be shorter than the first timer Tm1. With this configuration, when congestion occurs, the terminal device 10 can discard packets earlier than before the first discard process was enabled. This can increase the possibility of resolving the congestion.

[0174] Thereafter, at time t4, the terminal device 10 receives second setting information from the base station device 20. Based on the second setting information, the terminal device 10 disables the first discard process. That is, the terminal device 10 switches the discard timer to be used from the second timer Tm2 to the first timer Tm1.

[0175] The second timer Tm2 may be set for each PSI. For example, multiple second timers Tm2-0, ..., Tm2-15 may be set for PSI values ​​0, ..., 15, respectively. In this example, the subscript of the second timer Tm2 indicates the corresponding PSI value. For example, the second timer Tm2-0 is used for data associated with PSI "0" (i.e., a PDU set). When the second timer Tm2-0 expires, the terminal device 10 discards the data associated with PSI "0".

[0176] The multiple second timers Tm2-0, ..., Tm2-15 may have different values ​​from one another. For example, the smaller the PSI value (i.e., the relatively higher the importance of the data associated with that PSI), the larger the value of the second timer Tm2 may be set to. For example, the value of the second timer Tm2-0 corresponding to PSI "0" may be the largest. The value of the second timer Tm2-15 corresponding to PSI "15" may be the smallest. With this configuration, the terminal device 10 can retain data with relatively high importance for a long time, while quickly discarding data with relatively low importance.

[0177] In Fig. 16, the flow up to time t1 is the same as in Fig. 15, and therefore a description thereof will be omitted. As shown in Fig. 16, the PDCP entity of the terminal device 10 receives a packet 1601 from an upper layer at time t2. The PSI associated with the packet 1601 is "1". The terminal device 10 starts a second timer Tm2-1 from time t2. The value of the second timer Tm2-1 may be smaller than the value of the first timer Tm1. When the second timer Tm2-1 expires, the terminal device 10 discards the packet 1601.

[0178] Thereafter, at time t3, the PDCP entity of the terminal device 10 receives packet 1602 from the upper layer. The PSI associated with packet 1602 is "2". The terminal device 10 starts a second timer Tm2-2 from time t3. The value of the PSI associated with packet 1602 is greater than the value of the PSI associated with packet 1601. In other words, the importance of packet 1602 is lower than the importance of packet 1601. Therefore, the value of the second timer Tm2-2 may be smaller than the value of the second timer Tm2-1. According to this configuration, the terminal device 10 can retain data having a relatively high importance for a longer period of time, while discarding data having a relatively low importance earlier.

[0179] Thereafter, at time t4, the terminal device 10 receives second setting information from the base station device 20. Based on the second setting information, the terminal device 10 disables the first discard process. That is, the terminal device 10 switches the discard timer to be used from the multiple second timers Tm2-0, ..., Tm2-15 to the first timer Tm1.

[0180] At least one of the second timers Tm2-0, ..., Tm2-15 may be longer than the first timer Tm1. For example, the second timer Tm2 (e.g., Tm2-0) corresponding to a small PSI may be longer than the first timer Tm1. This configuration allows the terminal device 10 to retain data of high importance for a relatively long time.

[0181] The terminal device 10 may enable the first discard process only for data that the terminal device 10 is holding (or buffering) at the time of receiving the first setting information. As shown in Fig. 17 , the PDCP entity of the terminal device 10 receives a packet 1701 from an upper layer at time t10. The PSI associated with the packet 1701 is "1". The terminal device 10 starts a first timer Tm1 from time t10.

[0182] At time t11, the terminal device 10 receives first setting information from the base station device 20. At time t11, the terminal device 10 still holds packet 1701. Therefore, the terminal device 10 enables the first discard process for packet 1701. That is, the terminal device 10 switches the discard timer it uses from the first timer Tm1 to the second timer Tm2-1. For example, the terminal device 10 may stop the first timer Tm1 at time t11 based on the reception of the first setting information, and instead consider that the second timer Tm2-1 was started at time t10. When the second timer Tm2-1 expires, the terminal device 10 discards packet 1701.

[0183] On the other hand, at time t12 after receiving the first configuration information, the PDCP entity of the terminal device 10 receives packet 1702 from an upper layer. The PSI associated with packet 1702 is "3". In this case, the terminal device 10 does not enable the first discard process for packet 1702. The terminal device 10 starts a first timer Tm1 from time t12. When the first timer Tm1 expires, the terminal device 10 discards packet 1702.

[0184] Although the above describes an example in which the second timer Tm2 is set for each PSI, the configuration of the second timer Tm2 is not limited to this example. For example, the second timer Tm2 may be set for each PSI range. For example, multiple second timers Tm2-a and Tm2-b may be set for a first PSI range (e.g., 0 to 6) and a second PSI range (e.g., 7 to 15), respectively. In this example, the second timer Tm2-a is used for data associated with the first PSI range (e.g., 0 to 6). The second timer Tm2-b is used for data associated with the second PSI range (e.g., 7 to 15). The value of the second timer Tm2-a may be greater than the value of the second timer Tm2-b.

[0185] The terminal device 10 may receive timer information related to one or more second timers Tm2 from the base station device 20. The base station device 20 may transmit an RRC message including the timer information to the terminal device 10. The timer information may be included in a PDCP-config IE, which is an example of an RRC information element (IE). In another example, the timer information may be included in the first configuration information.

[0186] The terminal device 10 may enable the first discarding process based on PSI threshold information related to the PSI threshold Pth. The PSI threshold information may be configured in advance in the terminal device 10. In another example, the terminal device 10 may receive the PSI threshold information from the base station device 20. For example, the base station device 20 may transmit an RRC message including the PSI threshold information to the terminal device 10. The PSI threshold information may be included in a PDCP-config IE, which is an example of an RRC information element (IE). In another example, the PSI threshold information may be included in the first configuration information. For example, the terminal device 10 may enable the first discarding process for PSIs greater than the PSI threshold Pth. For example, assume that the PSI threshold Pth is "5." The terminal device 10 may consider that data associated with a PSI of "5" or greater is of low importance and may enable the first discarding process only for data with a PSI in the range of 5 to 15. That is, the terminal device 10 may perform data discard processing using a first timer Tm1 for data with a PSI in the range of 0 to 4, and may perform data discard processing (i.e., first discard processing) using multiple second timers Tm2-5, ..., Tm2-15 for data with a PSI in the range of 5 to 15.

[0187] 1.10.2 Second Discarding Process The PDCP entity of the terminal device 10 may execute a second discarding process based on the PSI. For example, the terminal device 10 may enable the second discarding process for data associated with a PSI equal to or greater than the PSI threshold Pth indicated by the PSI threshold information. The second discarding process may be a process of discarding data associated with a PSI equal to or greater than the PSI threshold Pth without using a discard timer (i.e., the first timer Tm1) for the data.

[0188] 18 , the PDCP entity of the terminal device 10 receives a packet 1801 from an upper layer at time t20. The terminal device 10 starts a first timer Tm1 from time t20. When the first timer Tm1 expires, the terminal device 10 discards the packet 1801.

[0189] At time t21, the PDCP entity of the terminal device 10 receives a packet 1802 from an upper layer. The PSI associated with the packet 1802 is "10." The terminal device 10 starts a first timer Tm1 from time t21.

[0190] At time t22, the terminal device 10 receives first setting information from the base station device 20. The first setting information may include PSI threshold information. For example, assume that the PSI threshold Pth is "5." The terminal device 10 enables the second discard process for packets with a PSI in the range of 5 to 15.

[0191] At the time of receiving the first setting information, the terminal device 10 is holding the packet 1802. Furthermore, the PSI "10" associated with the packet 1802 is equal to or greater than the PSI threshold Pth. Therefore, the terminal device 10 discards the packet 1802.

[0192] In this example, the terminal device 10 keeps the second discard process enabled until it receives second setting information from the base station device 20. The PDCP entity of the terminal device 10 receives packet 1803 from an upper layer at time t23. The PSI associated with packet 1803 is "8". Therefore, the terminal device 10 enables the second discard process for packet 1803. The terminal device 10 discards packet 1803 without using the first timer Tm1.

[0193] Meanwhile, the PDCP entity of the terminal device 10 receives packet 1804 from an upper layer at time t24. The PSI associated with packet 1804 is "1". Therefore, the terminal device 10 starts a first timer Tm1 from time t24 without enabling the second discard process for packet 1804. When the first timer Tm1 expires, the terminal device 10 discards packet 1804.

[0194] According to this configuration, the terminal device 10 can retain data having a relatively high level of importance for a long time, while discarding data having a relatively low level of importance more quickly.

[0195] After that, at time t25, the terminal device 10 receives second setting information from the base station device 20. The terminal device 10 disables the second discard process based on the second setting information.

[0196] The terminal device 10 may enable the second discard process only for data that the terminal device 10 is holding (or buffering) at the time of receiving the first setting information. In Fig. 19, the flow up to time t22 is the same as in Fig. 18, and therefore a description thereof will be omitted.

[0197] 19 , the terminal device 10 does not enable the second discard process for packets received after time t22. The PDCP entity of the terminal device 10 receives packet 1803 from an upper layer at time t23. The PSI associated with packet 1803 is "8". The terminal device 10 starts a first timer Tm1 from time t23 without enabling the second discard process for packet 1803. When the first timer Tm1 expires, the terminal device 10 discards packet 1803.

[0198] 1.11 Calculation of Delay Information Included in Delay Information Report When the terminal device 10 enables the first discard process, the terminal device 10 uses the second timer Tm2. Assume that the base station device 20 receives a delay information report while the terminal device 10 enables the first discard process. It is difficult for the base station device 20 to determine whether the remaining time included in the delay information report was calculated based on the first timer Tm1 or the second timer Tm2. As a result, the base station device 20 may incorrectly recognize the remaining time.

[0199] In consideration of the above, the terminal device 10 may calculate the remaining time included in the delay information report based on the first timer Tm1 even while the first discard process is enabled. That is, the terminal device 10 may always calculate the remaining time included in the delay information report based on the first timer Tm1. Below, a first aspect and a second aspect of this configuration will be described.

[0200] 1.11.1. First Aspect The terminal device 10 may use both the first timer Tm1 and the second timer Tm2 while the first discard process is enabled. As shown in FIG. 20 , the PDCP entity of the terminal device 10 receives a packet 2001 from an upper layer at time t30. The terminal device 10 starts the first timer Tm1 and the second timer Tm2 from time t30. The terminal device 10 uses the first timer Tm1 to calculate the remaining time to be included in the delay information report. The terminal device 10 includes the remaining time calculated based on the first timer Tm1 in the delay information report as delay information. On the other hand, the terminal device 10 uses the second timer Tm2 to discard the packet 2001. The second timer Tm2 expires at time t31. When the second timer Tm2 expires, the terminal device 10 discards the packet 2001.

[0201] 1.11.2 Second Aspect The terminal device 10 may use only the first timer Tm1 while the first discarding process is enabled. In this case, the terminal device 10 may use the discard threshold Dth. The discard threshold Dth is a threshold used to determine whether to discard data while the first discarding process is enabled, and is used for the first timer Tm1.

[0202] As shown in FIG. 21 , the PDCP entity of the terminal device 10 receives a packet 2101 from an upper layer at time t40. The terminal device 10 starts a first timer Tm1 from time t40. The terminal device 10 calculates the remaining time to be included in the delay information report based on the first timer Tm1. The terminal device 10 includes the remaining time calculated based on the first timer Tm1 in the delay information report as delay information. Meanwhile, the terminal device 10 also uses the first timer Tm1 for discarding the packet 2101. Here, the terminal device 10 uses the discard threshold Dth while the first discard process is enabled. If the remaining time of the first timer Tm1 falls below the discard threshold Dth, the terminal device 10 discards the packet 2101. In this way, the discard threshold Dth has substantially the same function as the second timer Tm2 described above.

[0203] The discard threshold Dth may be set in advance in the terminal device 10. In another example, the terminal device 10 may receive the discard threshold Dth from the base station device 20. For example, the base station device 20 may transmit an RRC message including the discard threshold Dth to the terminal device 10. The discard threshold Dth may be included in a PDCP-config IE, which is an example of an RRC information element (IE). In another example, the discard threshold Dth may be included in the first configuration information.

[0204] According to the first and second aspects described above, it is possible to reduce the possibility that the base station device 20 will erroneously recognize the remaining time.

[0205] 2. First Embodiment Next, the configuration of the first embodiment will be described. Hereinafter, the remaining time calculated based on the first timer Tm1 will be referred to as the "first remaining time RT1." Furthermore, the remaining time calculated based on the second timer Tm2 will be referred to as the "second remaining time RT2."

[0206] For example, the terminal device 10 triggers a delay information report based on a first threshold Th1. In the first aspect described above, such a triggering process may result in delay information reporting not being triggered at the appropriate time. As shown in FIG. 22 , the terminal device 10 calculates a second remaining time RT2 based on a second timer Tm2 while the first discarding process is enabled. Then, when the second remaining time RT2 falls below the first threshold Th1, the terminal device 10 triggers a delay information report. The value of the second timer Tm2 may be smaller than the value of the first timer Tm1. Therefore, the second remaining time RT2 reaches the first threshold Th1 more quickly than when the first remaining time RT1 is calculated using the first timer Tm1. This may result in the terminal device 10 frequently triggering delay information reporting. In other words, when congestion occurs, the terminal device 10 frequently performs uplink transmission, reducing the likelihood of resolving the congestion.

[0207] Furthermore, even in the second aspect, the above trigger process may fail to trigger a delay information report at an appropriate time. As shown in FIG. 23 , while the first discard process is enabled, the terminal device 10 calculates a first remaining time RT1 based on a first timer Tm1. Then, when the first remaining time RT1 falls below a first threshold Th1, the terminal device 10 triggers a delay information report. However, there are cases where the period tp1 set between the first threshold Th1 and the discard threshold Dth is too short. The period tp1 is not long enough for the base station device 20 to reschedule uplink communication after receiving the delay information report, and the base station device 20 may not be able to reschedule in time.

[0208] In consideration of the above, the terminal device 10 uses a second threshold Th2, which is different from the first threshold Th1, as the threshold for triggering a delay information report when the first discard process is enabled. That is, the terminal device 10 triggers a delay information report based on the first threshold Th1 when the first discard process is not enabled (i.e., in the first state), and triggers a delay information report based on the second threshold Th2 when the first discard process is enabled (i.e., in the second state). In other words, the terminal device 10 switches the threshold for triggering a delay information report from the first threshold Th1 to the second threshold Th2 based on the enablement of the first discard process. In the above configuration, the terminal device 10 may transmit a delay information report according to the following procedure.

[0209] As shown in FIG. 24 , the communication unit 220 of the base station device 20 transmits information indicating the first threshold Th1 and the second threshold Th2 to the terminal device 10 (S2401). The first threshold Th1 and the second threshold Th2 may be set for the LCH. For example, the first threshold Th1 and the second threshold Th2 may be set as new elements of the LogicalChannelConfig IE. The first threshold Th1 and the second threshold Th2 may be set for the LCG. For example, the first threshold Th1 and the second threshold Th2 may be set as new elements of the LogicalChannelGroup IE. The first threshold Th1 and the second threshold Th2 may be set for a PDU or a PDU set. The first threshold Th1 and the second threshold Th2 may be set in an IE related to a PDU or a PDU set included in an RRC message. The first threshold Th1 and the second threshold Th2 may be set for a data burst. The first threshold Th1 and the second threshold Th2 may be set in IEs related to a data burst included in an RRC message. The first threshold Th1 and the second threshold Th2 may be set for the terminal device 10. Note that the base station device 20 may transmit system information (SI, for example, SIB1 and / or an SIB other than SIB1) including information indicating the first threshold Th1 and the second threshold Th2 to the terminal device 10. The base station device 20 may transmit DCI including information indicating the first threshold Th1 and the second threshold Th2 to the terminal device 10.

[0210] The control unit 110 of the terminal device 10 triggers a delay information report based on a first threshold Th1. The control unit 110 triggers a delay information report when the first remaining time RT1 falls below the first threshold Th1. The communication unit 120 of the terminal device 10 transmits the delay information report to the base station device 20 (S2402). Note that, similar to the configuration described above, the control unit 110 may trigger a BSR including a delay information report based on the first threshold Th1.

[0211] The communication unit 120 receives first setting information from the base station device 20 (S2403). The control unit 110 enables the first discarding process based on the first setting information. Furthermore, the control unit 110 switches the threshold to be used from the first threshold Th1 to the second threshold Th2. Note that the control unit 110 keeps the first discarding process enabled until it receives second setting information from the base station device 20.

[0212] The information indicating the second threshold value Th2 may be included in the first setting information. That is, the terminal device 10 may receive the information indicating the first threshold value Th1 in step S2401 and the information indicating the second threshold value Th2 in step S2403.

[0213] The control unit 110 triggers a delay information report based on the second threshold value Th2. The communication unit 120 transmits the delay information report to the base station device 20 (S2404). Note that, similar to the configuration described above, the control unit 110 may trigger a BSR including a delay information report based on the second threshold value Th2.

[0214] Next, a specific process for triggering a delay information report will be described for each of the first and second aspects.

[0215] 2.1. First Aspect As shown in FIG. 25 , when the first discard process is enabled, the control unit 110 triggers a delay information report using a second timer Tm2 and a second threshold Th2. Specifically, the control unit 110 triggers a delay information report when the second remaining time RT2 falls below the second threshold Th2. The second threshold Th2 is different from the first threshold Th1. For example, the second threshold Th2 may be smaller than the first threshold Th1. This configuration enables a delay information report to be triggered at an appropriate timing. Specifically, the time it takes for the second remaining time RT2 to reach the second threshold Th2 is longer than when the first threshold Th1 is used (e.g., the example of FIG. 22 ). Therefore, the possibility that the terminal device 10 frequently triggers a delay information report can be reduced. That is, the possibility that the terminal device 10 frequently performs uplink transmissions in a congestion situation can be reduced.

[0216] In this aspect, the control unit 110 may use the first timer Tm1 to calculate the delay information to be included in the delay information report. The control unit 110 may include the first remaining time RT1 calculated based on the first timer Tm1 as delay information in the delay information report.

[0217] As described above, the second timer Tm2 may be set for each PSI. For example, multiple second timers Tm2-0, ..., Tm2-15 may be set for PSI values ​​of 0, ..., 15, respectively. The multiple second timers Tm2-0, ..., Tm2-15 may have different values ​​from each other. In this configuration, multiple second thresholds Th2-0, ..., Th2-15 may be set for PSI values ​​of 0, ..., 15, respectively. Hereinafter, the subscript of the second threshold Th2 indicates the corresponding PSI value. For example, the second threshold Th2-0 is used for the second timer Tm2-0 corresponding to PSI "0."

[0218] The multiple second thresholds Th2-0, ..., Th2-15 may be different values ​​from one another. For example, the smaller the PSI value (i.e., the relatively higher the importance of the data), the larger the value of the second timer Tm2 may be set to. In this case, the smaller the PSI value, the larger the value of the second threshold Th2 may be set to. For example, the value of the second threshold Th2-0 corresponding to a PSI of "0" may be the largest. The value of the second threshold Th2-15 corresponding to a PSI of "15" may be the smallest.

[0219] As described above, the second timer Tm2 may be set for each PSI range. For example, a plurality of second timers Tm2-a and Tm2-b may be set for a first PSI range (e.g., 0 to 6) and a second PSI range (e.g., 7 to 15), respectively. The value of the second timer Tm2-a may be greater than the value of the second timer Tm2-b. In this configuration, a plurality of second thresholds Th2-a and Th2-b may be set for the first PSI range and the second PSI range, respectively. The second threshold Th2-a may be greater than the second threshold Th2-b.

[0220] 2.2. Second Aspect As shown in FIG. 26 , when the first discard process is enabled, the control unit 110 triggers a delay information report using a first timer Tm1 and a second threshold Th2. Specifically, the control unit 110 triggers a delay information report when the first remaining time RT1 falls below the second threshold Th2. The second threshold Th2 is different from the first threshold Th1. For example, the second threshold Th2 may be greater than the first threshold Th1. This configuration enables the delay information report to be triggered at an appropriate timing. Specifically, the period tp2 set between the second threshold Th2 and the discard threshold Dth is longer than the period tp1 when the first threshold Th1 is used. In other words, the period from when the delay information report is triggered to when the packet is discarded is longer, thereby increasing the likelihood that the base station device 20 will be able to reschedule in time.

[0221] As described above, a plurality of second thresholds Th2-0, ..., Th2-15 may be set for PSI values ​​of 0, ..., 15, respectively. For example, the smaller the PSI value (i.e., the higher the importance of the data), the larger the value of the second threshold Th2 may be set. According to this configuration, the terminal device 10 can trigger a delay information report more quickly when data of relatively high importance exists. The base station device 20 can perform rescheduling for data of relatively high importance more quickly.

[0222] In another example, multiple discard thresholds Dth-0, ..., Dth-15 may be set for PSI values ​​0, ..., 15, respectively. Hereinafter, the subscript of the discard threshold Dth indicates the corresponding PSI value. For example, the discard threshold Dth-0 is used for data associated with PSI "0." The multiple discard thresholds Dth-0, ..., Dth-15 may be different from each other. In such a configuration, multiple second thresholds Th2-0, ..., Th2-15 may be set for PSI values ​​0, ..., 15, respectively. The multiple second thresholds Th2-0, ..., Th2-15 may be different from each other. For example, the multiple second thresholds Th2-0, ..., Th2-15 may be set so as to increase the likelihood that the base station device 20 will be able to reschedule the period tp2 in time. That is, the plurality of second thresholds Th2-0, . . . , Th2-15 may be set so that the period tp2 is longer than the period tp1.

[0223] 2.3. Modifications - Modification 1 The second threshold Th2 may be calculated based on the first threshold Th1 and an offset value relative to the first threshold Th1. The terminal device 10 may calculate the second threshold Th2 by adding or subtracting the offset value to the first threshold Th1. The offset value may be notified to the terminal device 10 in the same manner as the notification method for the first threshold Th1. The offset value may be included in the first setting information.

[0224] - Variation 2 When the PSI-based discard process (including the first discard process and the second discard process) is enabled, the terminal device 10 may trigger a BSR and / or a delay information report. That is, the terminal device 10 may trigger a BSR and / or a delay information report based on the reception of the first setting information. When the PSI-based discard process is enabled, data is discarded, and a change in the buffer status in the terminal device 10 may occur. Because the terminal device 10 triggers a BSR and / or a delay information report in response to the reception of the first setting information, the base station device 20 can quickly recognize a change in the buffer status in the terminal device 10.

[0225] In this configuration, the terminal device 10 may trigger a BSR and / or a delay information report based on the PSI. For example, the first setting information includes a PSI threshold Pth. The terminal device 10 determines, at the time of receiving the first setting information, whether data associated with a PSI below the PSI threshold Pth (i.e., data with relatively high importance) exists. If data associated with a PSI below the PSI threshold Pth exists, the terminal device 10 may trigger a BSR and / or a delay information report for the data associated with a PSI below the PSI threshold Pth.

[0226] On the other hand, it is assumed that there is data associated with a PSI equal to or greater than the PSI threshold Pth (i.e., data with relatively low importance) at the time of receiving the first configuration information. In this case, the terminal device 10 does not need to trigger a BSR and / or a delay information report for the data associated with a PSI equal to or greater than the PSI threshold Pth.

[0227] - Variation 3 The terminal device 10 may enable the PSI-based discard process (including the first discard process and the second discard process) based on whether at least one of the second timer Tm2, ​​the second threshold Th2, and the discard threshold Dth is set.

[0228] For example, when at least one of the second timer Tm2, ​​the second threshold Th2, and the discard threshold Dth is set, the terminal device 10 may enable reception of the first setting information and the second setting information. That is, when at least one of the second timer Tm2, ​​the second threshold Th2, and the discard threshold Dth is set, the terminal device 10 may enable the PSI-based discard process.

[0229] On the other hand, if none of the second timer Tm2, ​​the second threshold Th2, and the discard threshold Dth are set, the terminal device 10 does not need to enable reception of the first setting information and the second setting information. That is, if none of the second timer Tm2, ​​the second threshold Th2, and the discard threshold Dth are set, the terminal device 10 does not need to enable the PSI-based discard process.

[0230] 3. Second Embodiment Next, a configuration of a second embodiment will be described. The configuration of the first embodiment and its modified examples can be applied to the configuration described in this embodiment as long as there is no mutual contradiction.

[0231] The PSI level setting may vary depending on the implementation of the terminal device 10 and / or the implementation of the application. For example, assume that a first application (e.g., a remote driving application) of a certain terminal device 10 considers data associated with a PSI value in the range of 0 to 10 to be highly important. On the other hand, assume that a second application (an AR-related application) of another terminal device 10 considers data associated with a PSI value in the range of 0 to 5 to be highly important. In this manner, the criteria for determining high importance (i.e., the PSI value) may differ for each terminal device 10 and / or each application. Therefore, the base station device 20 cannot recognize how to configure (or enable) the PSI-based discard process for each terminal device 10 and / or each application. For example, when enabling the first discard process, the base station device 20 cannot recognize how to configure the second timer Tm2 and / or the second threshold Th2. Furthermore, when enabling the second discard process, the base station device 20 cannot recognize how to configure the PSI threshold Pth. If the base station device 20 enables the PSI-based discard process in the same way for all terminal devices and / or applications, there is a possibility that the service cannot be maintained.

[0232] Therefore, in this embodiment, the terminal device 10 transmits (or reports) information regarding PSI preference to the base station device 20. Hereinafter, the above information will be referred to as "PSI preference information." The "PSI preference information" includes a PSI level preference (a preference for setting the PSI level).

[0233] In XR, the terminal device 10 may transmit UE assistance information (UAI) for each QoS flow to the base station device 20. In this configuration, the terminal device may include PSI preference information in the UAI message.

[0234] The UAI message may include uplink assistance information. The uplink assistance information may include at least one of a burst arrival time, an uplink jitter, and an uplink data burst periodicity. In this configuration, the terminal device 10 may include PSI preference information in the uplink assistance information.

[0235] In addition, the terminal device 10 may transmit the PSI preference information using a message other than the UAI message or other signaling.

[0236] The PSI preference information may be information indicating a level, value, or range of PSI that the terminal device 10 and / or application considers high or low. In another example, the PSI preference information may be information indicating a level, value, or range of PSI for which PSI-based discarding should be enabled or disabled.

[0237] The terminal device 10 may transmit PSI preference information for each QoS flow, serving cell, or cell group to the base station device 20. That is, PSI preference information for each QoS flow, serving cell, or cell group may be transmitted.

[0238] The terminal device 10 may obtain or determine the PSI preferences based on, for example, applications installed on the terminal device 10 .

[0239] The terminal device 10 may transmit a UAI message according to the following procedure. As shown in FIG. 27 , the communication unit 220 of the base station device 20 transmits third setting information related to the UAI to the terminal device 10 (S2701). The third setting information may be included in an RRC message. The third setting information may be included in an IE related to PSI preference. The third setting information may include instruction information indicating that the terminal device 10 transmits PSI preference information. The third setting information may further include control information for controlling the transmission of PSI preference information by the terminal device 10. For example, the control information may include at least one of a period during which transmission is prohibited and a transmission cycle. For example, the control information may include information related to a prohibition timer TmP for prohibiting the terminal device 10 from transmitting PSI preference information.

[0240] The control unit 110 of the terminal device 10 generates a UAI message including PSI preference information based on the third setting information. The UAI message may further include the above-mentioned uplink auxiliary information. The communication unit 120 of the terminal device 10 transmits the UAI message (S2702). Note that the control unit 110 may control the transmission of the UAI message including the PSI preference information based on the prohibition timer TmP. The control unit 110 may transmit the UAI message including the PSI preference information when the prohibition timer TmP is not running.

[0241] According to the above configuration, the base station device 20 can receive PSI preferences from the terminal device 10. The base station device 20 can recognize information related to PSI regarding uplink communication from the terminal device 10. The base station device 20 may set a PSI level according to the PSI preference information transmitted from the terminal device 10. For example, the base station device 20 may set a PSI level equal to the PSI preference information transmitted from the terminal device 10 (e.g., the PSI level indicated in the PSI preference information). For example, the base station device 20 can recognize how to configure (or enable) the PSI-based discard process for each terminal device 10 and / or each application. The base station device 20 may enable the PSI-based discard process as described above based on the PSI preference information. The base station device 20 can appropriately configure the PSI-based discard process for the terminal device 10.

[0242] In another example, the terminal device 10 may transmit a UAI message including PSI preference information as follows: When a predetermined IE (e.g., otherConfig IE) included in an RRC message received from the base station device 20 includes an IE related to the transmission of PSI preference (e.g., PSI-PreferenceConfig IE), and the IE related to the transmission of PSI preference has a value (e.g., setup) indicating that a UAI message including PSI preference information is to be transmitted, the terminal device 10 may consider itself to be configured to provide a UAI message including PSI preference information. On the other hand, when the IE related to the transmission of PSI preference does not have a value indicating that a UAI message including PSI preference information is to be transmitted, or when the IE related to the transmission of PSI preference information is not included in the RRC message, the terminal device 10 may consider itself to be configured not to provide a UAI message including PSI preference information, and / or may stop a predetermined timer Tmx.

[0243] When configured to provide a UAI message including PSI preference information, the terminal device 10 may set a predetermined timer Tmx to a prohibition timer TmP, start the timer Tmx, and initiate transmission of a UAI message including the current PSI preference information when the following condition (b1) or (b2) is satisfied: (b1) the terminal device 10 has a preference for PSI, and / or has not yet sent a UAI message including the preference (i.e., PSI preference information) since being configured to provide the preference; or (b2) the current preference for PSI is different from the preference when the terminal device 10 last sent a UAI message including PSI preference information, and / or the predetermined timer Tmx (i.e., prohibition timer TmP) is not running.

[0244] When transmission of a UAI message including PSI preference information is started, the terminal device 10 may generate the UAI message as follows: If the terminal device 10 has a preference regarding PSI, the terminal device 10 may include an IE regarding PSI preference (e.g., PSI-Preference IE) in the UAI message and / or set the PSI preference information in the IE; If the terminal device 10 does not have a preference regarding PSI, the terminal device 10 does not need to include the above-mentioned IE regarding PSI preference in the UAI message.

[0245] 4. Modifications Although the present disclosure has been described based on the above embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the equivalent range. Other combinations including one or more elements included in the above embodiment are also within the scope and spirit of the present disclosure.

[0246] The words, phrases, and other expressions used in the above embodiments are merely examples and may be replaced with substantially identical or similar expressions. In particular, since the technology according to the above embodiments relates to technical specifications, the expressions in the above embodiments may be replaced with substantially identical or similar expressions in technical specifications (e.g., technical specifications cited in this specification).

[0247] The information transmitted and received in the above embodiment may be contained in the same or a different message or element already described in the technical specifications, or may be contained in a newly defined message or element. The information transmitted and received in the above embodiment may be transmitted and received using a different layer and / or a different channel than those in the above embodiment.

[0248] The means and / or functions provided by the devices described in the above embodiments can be provided by software recorded in a tangible memory device and a computer that executes the software, software alone, hardware alone, or a combination thereof. For example, if any of the above devices is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a large number of logic circuits, or an analog circuit.

[0249] The device described in the above embodiment executes a program stored in a non-transitory tangible storage medium, and the execution of the program executes a method corresponding to the program.

[0250] 5. Supplementary Notes Some or all of the above embodiments and modified examples may also be described as in the following supplementary notes, but are not limited to the contents of the supplementary notes. Below, a relationship is expressed in which a supplementary note that is dependent on multiple supplementary notes is dependent on another supplementary note that is dependent on multiple supplementary notes. All of the dependency relationships of the supplementary notes expressed below are included in the above embodiments.

[0251] (Supplementary Note A1) A terminal device (10) comprising: a control unit (110) configured to trigger a delay information report including delay information; and a communication unit (120) configured to transmit the delay information report to a base station device (20), wherein the control unit is configured to: use a first threshold (Th1) as a threshold for triggering the delay information report when a data discard process based on a Protocol Data Unit Set Importance (PSI) is not enabled; and use one or more second thresholds (Th2) different from the first threshold as a threshold for triggering the delay information report when a data discard process based on the PSI is enabled.

[0252] (Supplementary Note A2) The terminal device according to Supplementary Note A1, wherein the control unit is configured to: execute data discard processing using a first timer which is a discard timer when data discard processing based on the PSI is not enabled; and execute data discard processing using one or more second timers which are discard timers when data discard processing based on the PSI is enabled; the first threshold value is a threshold value for the remaining time of the first timer; and the one or more second threshold values ​​are threshold values ​​for the remaining time of the one or more second timers.

[0253] (Supplementary Note A3) The terminal device according to Supplementary Note A2, wherein the one or more second timers are shorter than the first timer, and the one or more second thresholds are smaller than the first threshold.

[0254] (Supplementary Note A4) The terminal device according to Supplementary Note A2 or A3, wherein the control unit is configured to include the remaining time of the first timer as the delay information in the delay information report when a data discard process based on the PSI is enabled.

[0255] (Supplementary Note A5) The terminal device according to any one of Supplementary Notes A2 to A4, wherein the control unit is configured to trigger the delay information report using the plurality of second thresholds when a data discard process based on the PSI is enabled, and the plurality of second thresholds are set for each of the PSI.

[0256] (Supplementary Note A6) The terminal device according to Supplementary Note A5, wherein the control unit is configured to, when the data discard process based on the PSI is enabled, execute the data discard process using the plurality of second timers as the discard timers, and the plurality of second timers are set for each of the PSIs.

[0257] (Supplementary Note A7) The terminal device according to Supplementary Note A1, wherein the control unit is configured to: execute data discard processing using a first timer that is a discard timer when data discard processing based on the PSI is not enabled; and execute data discard processing using the first timer and a discard threshold for the remaining time of the first timer when data discard processing based on the PSI is enabled; the first threshold is a threshold for the remaining time of the first timer; and the one or more second thresholds are thresholds for the remaining time of the first timer.

[0258] (Supplementary Note A8) The terminal device according to Supplementary Note A7, wherein the one or more second thresholds are greater than the first threshold.

[0259] (Supplementary Note A9) The terminal device according to Supplementary Note A7 or A8, wherein the control unit is configured to include the remaining time of the first timer as the delay information in the delay information report when a data discard process based on the PSI is enabled.

[0260] (Supplementary Note A10) The terminal device according to any one of Supplementary Notes A7 to A9, wherein the control unit is configured to trigger the delay information report using the plurality of second thresholds when a data discard process based on the PSI is enabled, and the plurality of second thresholds are set for each of the PSI.

[0261] (Supplementary Note A11) The terminal device according to any one of Supplementary Notes A1 to A10, wherein the control unit is configured to calculate the second threshold based on the first threshold and an offset value for the first threshold.

[0262] (Supplementary Note A12) The terminal device according to any one of Supplementary Notes A1 to A11, wherein the communication unit is configured to receive, from the base station device, setting information indicating that a process of discarding data based on the PSI is to be enabled, and the control unit is configured to enable the process of discarding data based on the PSI based on the setting information.

[0263] (Supplementary Note A13) The terminal device according to Supplementary Note A12, wherein the setting information includes information related to the second threshold.

[0264] (Supplementary Note A14) The terminal device according to Supplementary Note A12, wherein the control unit is configured to trigger the delay information report when the setting information is received.

[0265] (Supplementary Note A15) The terminal device according to Supplementary Note A12, wherein the setting information includes information on a PSI threshold that is a threshold value of the PSI, and the control unit is configured to trigger the delay information report for data associated with the PSI that is below the PSI threshold.

[0266] (Supplementary Note A16) The terminal device according to Supplementary Note A15, wherein the control unit is configured not to trigger the delay information report for data associated with the PSI equal to or greater than the PSI threshold.

[0267] (Supplementary Note A17) The terminal device according to any one of Supplementary Notes A1 to A16, wherein the delay information report is a Buffer Status Report (BSR) including the delay information and buffer size information related to a buffer size.

[0268] (Supplementary Note A18) A method for a terminal device (10), comprising: triggering a delay information report including delay information; and transmitting the delay information report to a base station device (20), wherein triggering the delay information report comprises: using a first threshold (Th1) as a threshold for triggering the delay information report when a data discard process based on a Protocol Data Unit Set Importance (PSI) is not enabled; and using one or more second thresholds (Th2) different from the first threshold as a threshold for triggering the delay information report when a data discard process based on the PSI is enabled.

[0269] (Supplementary Note A19) A program that causes a processor (101) in a terminal device (10) to execute the following: triggering a delay information report including delay information; and transmitting the delay information report to a base station device (20), wherein triggering the delay information report includes: using a first threshold (Th1) as a threshold for triggering the delay information report when a data discard process based on a Protocol Data Unit Set Importance (PSI) is not enabled; and using one or more second thresholds (Th2) different from the first threshold as a threshold for triggering the delay information report when a data discard process based on the PSI is enabled.

[0270] (Supplementary Note A20) A non-transitive tangible recording medium having recorded thereon a program that causes a processor (101) in a terminal device (10) to execute the following: triggering a delay information report including delay information; and transmitting the delay information report to a base station device (20), wherein triggering the delay information report includes: using a first threshold (Th1) as a threshold for triggering the delay information report when a data discard process based on a Protocol Data Unit Set Importance (PSI) is not enabled; and using one or more second thresholds (Th2) different from the first threshold as a threshold for triggering the delay information report when a data discard process based on the PSI is enabled.

[0271] (Supplementary Note B1) A terminal device (10) comprising: a control unit (110) including a Packet Data Convergence Protocol (PDCP) entity; and a receiving unit (122) that receives, from a base station device (20), a Radio Resource Control (RRC) message including information for setting a first timer, wherein the PDCP entity starts the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer, and when the receiving unit receives an RRC message including information for setting a second timer and receives, using a Medium Access Control (MAC) control element (CE), information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled, starts the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

[0272] (Supplementary Note B2) The terminal device according to Supplementary Note B1, wherein the PDCP entity starts the first timer associated with the PDCP SDU based on reception of the PDCP SDU from the upper layer when the receiving unit receives the RRC message including the information for setting the second timer and also receives, using the MAC CE, information indicating that the PSI-based discard process is to be disabled.

[0273] (Supplementary Note B3) The terminal device according to Supplementary Note B1 or B2, wherein the first timer and the second timer are set for a data radio bearer (DRB), and the value of the second timer is set to be shorter than the value of the first timer.

[0274] (Supplementary Note B4) The terminal device according to any one of Supplementary Notes B1 to B3, wherein the PDCP entity, when the first timer expires, discards the PDCP SDU associated with the first timer and / or a PDCP data Protocol Data Unit (PDU) corresponding to the PDCP SDU, and when the second timer expires, discards the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

[0275] (Supplementary Note B5) A method for a terminal device (10), comprising: receiving, from a base station device (20), a Radio Resource Control (RRC) message including information for setting a first timer; and starting, in a Packet Data Convergence Protocol (PDCP) entity, the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer; and further comprising: receiving an RRC message including information for setting a second timer, and, when information indicating that a Protocol Data Unit Set Importance (PSI) based discard process is enabled is received using a Medium Access Control (MAC) control element (CE), starting, in the PDCP entity, the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

[0276] (Supplementary Note B6) The method according to Supplementary Note B5, comprising: when receiving the RRC message including the information for setting the second timer and receiving, using the MAC CE, information indicating that the PSI-based discard process is to be disabled, starting, in the PDCP entity, the first timer associated with the PDCP SDU based on reception of the PDCP SDU from the upper layer.

[0277] (Supplementary Note B7) The method according to Supplementary Note B5 or B6, wherein the first timer and the second timer are set for a data radio bearer (DRB), and the value of the second timer is set to be shorter than the value of the first timer.

[0278] (Supplementary Note B8) The method according to any one of Supplementary Notes B5 to B7, comprising: when the first timer expires, in the PDCP entity, discarding the PDCP SDU associated with the first timer and / or a PDCP data Protocol Data Unit (PDU) corresponding to the PDCP SDU; and when the second timer expires, discarding the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

[0279] (Supplementary Note B9) A program causing a processor (101) in a terminal device (10) to execute: receiving a Radio Resource Control (RRC) message from a base station device (20) including information for setting a first timer; and starting, in a Packet Data Convergence Protocol (PDCP) entity, the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from an upper layer, the program further causing the processor to receive an RRC message including information for setting a second timer, and, when receiving, using a Medium Access Control (MAC) control element (CE), information indicating that a Protocol Data Unit Set Importance (PSI) based discard process is enabled, start, in the PDCP entity, the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the upper layer. Program.

[0280] (Supplementary Note B10) A non-transitory tangible recording medium having recorded thereon a program that causes a processor (101) in a terminal device (10) to execute the following: receive, from a base station device (20), a Radio Resource Control (RRC) message including information for setting a first timer; and, in a Packet Data Convergence Protocol (PDCP) entity, start the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from an upper layer, wherein the program causes the processor to: receive an RRC message including information for setting a second timer, and, when receiving, using a Medium Access Control (MAC) Control Element (CE), information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled, in the PDCP entity based on reception of the PDCP SDU from the upper layer, start the first timer associated with the PDCP SDU. starting the second timer associated with the SDU.

[0281] (Supplementary Note B11) A base station device (20) includes a transmitter (210) in a Packet Data Convergence Protocol (PDCP) entity of a terminal device (10) that transmits, to the terminal device, a Radio Resource Control (RRC) message including information for setting a first timer that is started based on reception of a PDCP service data unit (SDU) from a higher layer, wherein the transmitter transmits, to the terminal device, an RRC message including information for setting a second timer, and transmits, to the terminal device, information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled, using a Medium Access Control (MAC) Control Element (CE); and transmits the RRC message including the information for setting the second timer, and transmits, to the MAC Control Element (CE), the information indicating that the PSI-based discard process is enabled. When the PDCP SDU is transmitted using CE, the second timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the upper layer.

[0282] (Supplementary Note B12) The base station apparatus according to Supplementary Note B11, wherein the transmitter transmits, to the terminal device, the RRC message including the information for setting the second timer, and transmits, to the terminal device, information indicating that the PSI-based discard process is to be disabled, using the MAC CE; and when the transmitter transmits the RRC message including the information for setting the second timer, and transmits, to the terminal device, the information indicating that the PSI-based discard process is to be disabled, using the MAC CE, the first timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the higher layer.

[0283] (Supplementary Note B13) The base station device according to Supplementary Note B11 or B12, wherein the first timer and the second timer are set for a data radio bearer (DRB), and a value of the second timer is set to be shorter than a value of the first timer.

[0284] (Supplementary Note B14) The base station device according to any one of Supplementary Notes B11 to B13, comprising: a control unit (210) that controls, based on the first timer, discarding the PDCP SDU associated with the first timer and / or a PDCP data protocol data unit (PDU) corresponding to the PDCP SDU; and that controls, based on the second timer, discarding the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

[0285] (Supplementary Note B15) A method for a base station device (20), comprising: transmitting, in a Packet Data Convergence Protocol (PDCP) entity of a terminal device (10), a Radio Resource Control (RRC) message including information for setting a first timer, the first timer being started based on reception of a PDCP service data unit (SDU) from a higher layer; transmitting, to the terminal device, an RRC message including information for setting a second timer, and transmitting, to the terminal device, information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is to be enabled, using a Medium Access Control (MAC) Control Element (CE); wherein, when the RRC message including the information for setting the second timer has been transmitted and the information indicating that the PSI-based discard process is to be enabled has been transmitted using the MAC CE, the PDCP entity of the terminal device transmits, the second timer associated with the PDCP SDU is started based on reception of the SDU.

[0286] (Supplementary Note B16) A program causing a processor (201) in a base station device (20) to execute the following: transmitting, to a terminal device (10), a Radio Resource Control (RRC) message including information for setting a first timer, the first timer being started based on reception of a PDCP service data unit (SDU) from a higher layer, in a Packet Data Convergence Protocol (PDCP) entity of the terminal device; transmitting, to the terminal device, an RRC message including information for setting a second timer, and transmitting, to the terminal device, information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is to be enabled, using a Medium Access Control (MAC) Control Element (CE); When the transmission is performed using CE, the second timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the upper layer.

[0287] (Supplementary Note B17) A non-transient tangible recording medium having recorded thereon a program causing a processor (201) in a base station device (20) to execute the following: transmitting, to the terminal device, a Radio Resource Control (RRC) message including information for setting a first timer, the first timer being started based on reception of a PDCP service data unit (SDU) from a higher layer in a Packet Data Convergence Protocol (PDCP) entity of the terminal device; transmitting, to the terminal device, an RRC message including information for setting a second timer, and transmitting, to the terminal device, information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is to be enabled, using a Medium Access Control (MAC) Control Element (CE); When the PDCP SDU is transmitted using CE, the second timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the upper layer.

[0288] The disclosures of the above prior art documents and references are incorporated herein by reference.

Claims

1. A terminal device (10), comprising: a control unit (110) including a Packet Data Convergence Protocol (PDCP) entity; and a receiving unit (122) that receives a Radio Resource Control (RRC) message including information for setting a first timer from a base station device (20), wherein the PDCP entity starts the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer, and when the receiving unit receives an RRC message including information for setting a second timer and receives information indicating that a Protocol Data Unit Set Importance (PSI) based discard process is enabled using a Medium Access Control (MAC) control element (CE), starts the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

2. The terminal device according to claim 1, wherein when the receiving unit receives the RRC message including the information for setting the second timer and receives, using the MAC CE, information indicating that the PSI-based discard process is to be disabled, the PDCP entity starts the first timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

3. The terminal device according to claim 1 or 2, wherein the first timer and the second timer are set for a data radio bearer (DRB), and the value of the second timer is set to be shorter than the value of the first timer.

4. The terminal device according to any one of claims 1 to 3, wherein the PDCP entity, when the first timer expires, discards the PDCP SDU associated with the first timer and / or a PDCP data Protocol Data Unit (PDU) corresponding to the PDCP SDU, and when the second timer expires, discards the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

5. A method for a terminal device (10), comprising: receiving a Radio Resource Control (RRC) message from a base station device (20), the Radio Resource Control (RRC) message including information for setting a first timer; and starting, in a Packet Data Convergence Protocol (PDCP) entity, the first timer associated with a PDCP service data unit (SDU) based on reception of the PDCP SDU from a higher layer; and, when receiving an RRC message including information for setting a second timer and information indicating that a Protocol Data Unit Set Importance (PSI) based discard process is enabled using a Medium Access Control (MAC) control element (CE), starting, in the PDCP entity, the second timer associated with the PDCP SDU based on reception of the PDCP SDU from the higher layer.

6. The method of claim 5, further comprising: when receiving the RRC message including the information for setting the second timer and receiving, using the MAC CE, information indicating disabling the PSI-based discard process, starting, in the PDCP entity, the first timer associated with the PDCP SDU based on reception of the PDCP SDU from the upper layer.

7. The method according to claim 5 or 6, wherein the first timer and the second timer are set for a Data Radio Bearer (DRB), and the value of the second timer is set to be shorter than the value of the first timer.

8. The method according to any one of claims 5 to 7, comprising: when the first timer expires, in the PDCP entity, discarding the PDCP SDU associated with the first timer and / or a PDCP data Protocol Data Unit (PDU) corresponding to the PDCP SDU; and when the second timer expires, discarding the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

9. A base station device (20), comprising: a transmission unit (210) for transmitting, to a terminal device (10), a Radio Resource Control (RRC) message including information for setting a first timer, the first timer being started based on reception of a PDCP service data unit (SDU) from a higher layer, in a Packet Data Convergence Protocol (PDCP) entity of the terminal device (10); the transmission unit transmits, to the terminal device, an RRC message including information for setting a second timer, and transmits, to the terminal device using a Medium Access Control (MAC) control element (CE), information indicating that a Protocol Data Unit Set Importance (PSI)-based discard process is enabled; and when the transmission unit transmits the RRC message including the information for setting the second timer, and transmits, to the terminal device using the MAC CE, information indicating that the PSI-based discard process is enabled, the PDCP entity of the terminal device transmits, to the terminal device, a Radio Resource Control (RRC) message including information for setting a first timer, the first timer being started based on reception of a PDCP service data unit (SDU) from a higher layer. upon reception of the PDCP SDU, starting the second timer associated with the PDCP SDU.

10. The base station apparatus according to claim 9, wherein when the transmission unit transmits the RRC message including the information for setting the second timer to the terminal device and transmits information indicating that the PSI-based discard process is to be disabled to the terminal device using the MAC CE, and when the transmission unit transmits the RRC message including the information for setting the second timer and transmits the information indicating that the PSI-based discard process is to be disabled using the MAC CE, the first timer associated with the PDCP SDU is started in a PDCP entity of the terminal device based on reception of the PDCP SDU from the higher layer.

11. The base station device according to claim 9 or 10, wherein the first timer and the second timer are set for a data radio bearer (DRB), and the value of the second timer is set to be shorter than the value of the first timer.

12. The base station device according to any one of claims 9 to 11, comprising a control unit (210) that controls, based on the first timer, discarding the PDCP SDU associated with the first timer and / or a PDCP data protocol data unit (PDU) corresponding to the PDCP SDU, and that controls, based on the second timer, discarding the PDCP SDU associated with the second timer and / or a PDCP data PDU corresponding to the PDCP SDU.

Images