Terminal device, base station device, and method

Abstract

A terminal device (10) comprises: a control unit; and a communication unit configured so as to implement wireless communication as a result of being controlled by the control unit. With regard to one or more intermittent reception settings among a plurality of intermittent reception settings that can be set by a base station device (20), the control unit of the terminal device (10) is configured so as to transmit, to the base station device and through the communication unit, preference information indicating whether the terminal device is to use the one or more intermittent reception settings.

Description

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

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2022-099925, filed on June 21, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a terminal device, a base station device, and a method for supporting multiple discontinuous reception settings.

[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 38.331 V17.0.0 (2022-03)

[0006] In the above-mentioned XR implementation study, power consumption in the terminal device is one of the considerations. In XR, it is assumed that multiple data streams with different cycles are transmitted to the terminal device.

[0007] As a technology for reducing power consumption, discontinuous reception (DRX) is used, in which a physical downlink control channel (PDCCH) indicating information such as scheduling is discontinuously received. Non-Patent Document 2 describes various parameters related to discontinuous reception and transmission and reception of control information.

[0008] As a result of detailed investigations by the inventors, the following problem was found: The discontinuous reception technology described in Non-Patent Document 2 does not adequately anticipate multiple data streams with different characteristics, such as XR. Therefore, if the discontinuous reception technology is applied to XR as is, there is a possibility that power consumption will increase and that appropriate discontinuous reception operation will not be achieved.

[0009] The present disclosure achieves both reduced power consumption and appropriate intermittent reception operation.

[0010] A terminal device in one aspect of the present disclosure is a terminal device comprising a control unit and a communication unit configured to perform wireless communication by being controlled by the control unit, wherein the control unit is configured to transmit preference information to the base station device via the communication unit indicating whether the terminal device will use one or more intermittent reception settings out of a plurality of intermittent reception settings that can be set by the base station device.

[0011] In addition, a base station device in one aspect of the present disclosure is a base station device comprising a control unit and a communication unit configured to perform wireless communication by being controlled by the control unit, and the control unit is configured to receive preference information from the terminal device via the communication unit, indicating whether or not the terminal device will use one or more intermittent reception settings out of a plurality of intermittent reception settings that can be set for the terminal device.

[0012] Furthermore, a method according to one aspect of the present disclosure is a method comprising: generating, in a terminal device, preference information indicating whether or not the terminal device will use one or more intermittent reception settings among a plurality of intermittent reception settings that can be set by a base station device; and transmitting the preference information to the base station device.

[0013] According to the above configuration, the terminal device transmits preference information indicating whether or not to use one or more discontinuous reception settings to the base station device. Therefore, the terminal device can notify the base station device of the necessity of each discontinuous reception setting. As a result, for example, it is possible to release only unnecessary discontinuous reception settings from among multiple discontinuous reception settings, thereby achieving both reduced power consumption and appropriate discontinuous reception operation. Furthermore, as a result, for example, it is possible to maintain or add only necessary discontinuous reception settings, making it possible to perform appropriate discontinuous reception operation while suppressing increases in power consumption. Note that the above configuration may achieve other effects instead of or in addition to the above effect.

[0014] 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 illustrates a communication system S according to an embodiment, Fig. 2 illustrates a U-plane protocol stack according to an embodiment, Fig. 3 illustrates a C-plane protocol stack according to an embodiment, Fig. 4 is a block diagram illustrating a schematic hardware configuration of a terminal device 10 according to an embodiment, Fig. 5 is a block diagram illustrating a schematic functional configuration of the terminal device 10 according to an embodiment, Fig. 6 is a block diagram illustrating a schematic hardware configuration of a base station device 20 according to an embodiment, Fig. 7 is a block diagram illustrating a schematic functional configuration of the base station device 20 according to an embodiment, Fig. 8 is a diagram illustrating a radio frame configuration according to an embodiment, Fig. 9 is a diagram illustrating a radio resource control (RRC) state according to an embodiment, Fig. 10 is a schematic explanatory diagram of discontinuous reception (DRX) according to an embodiment, Fig. 11 is an explanatory diagram of multiple types of traffic according to an embodiment, and Fig. 12 is a sequence diagram of DRX setting according to an embodiment.

[0015] 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.

[0016] 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.

[0017] 1. Embodiment 1.1 Communication System As shown in Fig. 1, a communication system S of the embodiment includes one or more terminal apparatuses (Terminal Apparatus) 10, one or more base station apparatuses (Base Station Apparatus) 20, and a core network 30. The communication system S is configured in accordance with predetermined technical specifications (Technical Specifications, TS). For example, the communication system S may comply with technical specifications (e.g., 5G, 5G Advanced, 6G, etc.) defined by the Third Generation Partnership Project (3GPP).

[0018] 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.

[0019] 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.

[0020] 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.

[0021] The base station device 20 may be, for example, a gNB that provides a U-plane and a C-plane conforming to the 3GPP 5G NR (New Radio) specification to the terminal device 10 and connects to the 3GPP 5GC (5G Core Network). Alternatively, the base station device 20 may be a device conforming to other older or newer 3GPP specifications.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] 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.

[0026] As described above, 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 specification. The terminal device 10 may also be a device that complies with other older or newer 3GPP specifications.

[0027] 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).

[0028] 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.

[0029] 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.

[0030] 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 above-mentioned layers other than 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] The input / output interface 103 is an interface that receives operations on the terminal device 10 and supplies them to the processor 101, and also presents various information to the user, and is, for example, a touch panel.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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. The communication unit 120 may include a plurality of wireless interfaces 104 and a plurality of antennas 105.

[0039] The control unit 110 operates to execute various processes of the terminal device 10 of this embodiment.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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 .

[0044] 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 base station device 20 via the antenna 205.

[0045] 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.

[0046] 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. 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.

[0047] 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. The communication unit 220 may include a plurality of wireless interfaces 204 and a plurality of antennas 205.

[0048] 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).

[0049] The control unit 210 operates to execute various processes in the base station device 20 of this embodiment.

[0050] 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.

[0051] 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.

[0052] A cyclic prefix is ​​a redundant signal that functions as a guard period 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.

[0053] 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]

[0054] 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.

[0055] In the time domain of OFDM, a layered radio frame structure is used as shown in Figure 8. One radio frame includes 10 subframes. 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.

[0056] 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

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Each radio frame is assigned a system frame number (SFN) that counts up by one from 0 to 1023. 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, one cycle of the system frame number is 10,240 ms (= 10.24 seconds).

[0061] Furthermore, a hyper-system frame number (H-SFN) may be used. The hyper-system frame number is a number that counts up by one from 0 to 1023 for each cycle of the system frame number. Since one cycle of the system frame number is 10.24 seconds, one cycle of the hyper-system frame number is 10,485.76 seconds (= approximately 2.91 hours).

[0062] 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.

[0063] 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 (Initial DL-BWP) and / or a dedicated DL-BWP (Dedicated DL-BWP). Furthermore, the UL-BWP may include an initial UL-BWP (Initial UL-BWP) and / or a dedicated UL-BWP (Dedicated UL-BWP). Hereinafter, the BWP may include a DL-BWP and / or a UL-BWP.

[0064] 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.

[0065] The terminal device 10 and the base station device 20 transmit and receive user data and control information using a plurality of hierarchical channels. Physical channels are channels used for physical communication between the terminal device 10 and the base station device 20. Examples of physical channels include a Physical Downlink Control Channel (PDCCH), a Physical Broadcast Channel (PBCH), and a Physical Uplink Control Channel (PUCCH).

[0066] 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. Also, 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. Also, UL-SCH data includes user data in the uplink.

[0067] 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).

[0068] 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 other control information for the terminal device 10. The DCI is mapped to the PDCCH and corresponds to Layer 1 signaling.

[0069] Here, one or more formats may be defined for transmission of DCI in the PDCCH. The formats defined for transmission of DCI in the PDCCH may be referred to as DCI formats. For example, the DCI formats may include DCI formats used for scheduling a Physical Downlink Shared Channel (PDSCH) (e.g., formats referred to as DCI format 1_0, DCI format 1_1, and / or DCI format 1_2). Furthermore, for example, the DCI formats may include DCI formats used for scheduling a Physical Uplink Shared Channel (PUSCH) (e.g., formats referred to as DCI format 0_0, DCI format 0_1, and / or DCI format 0_2). Furthermore, the DCI formats may include DCI formats not used for scheduling the PDSCH and / or the PUSCH. The DCI formats used for scheduling the PDSCH and / or the PUSCH may be referred to as scheduling DCI formats. A DCI format that is not used for scheduling the PDSCH and / or PUSCH may be referred to as a non-scheduling DCI format. In this embodiment, 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."

[0070] 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.

[0071] 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.

[0072] That is, the terminal device 10 may monitor (and / or receive) the PDCCH and detect (and / or receive) the DCI format. Here, as will be described later, the terminal device 10 may perform monitoring (and / or reception) of the PDCCH during an active time in DRX operation.

[0073] 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.

[0074] The base station device 20 transmits a control element (CE) of the MAC layer to the terminal device 10 using the DL-SCH, which is a transport channel. The downlink MAC CE includes control information such as a DRX command (described later). The downlink MAC CE is mapped to the PDSCH via the DL-SCH and corresponds to Layer 2 signaling.

[0075] 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 the PUSCH via the UL-SCH and corresponds to Layer 2 signaling.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] As an example of an uplink RRC message, a user equipment assistance information (UE Assistance Information) message will be described. The user equipment assistance information 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 user equipment assistance information message. The user equipment assistance information message is used to notify the base station device 20 of various information related to the terminal device 10 (UE assistance information).

[0082] 1.4 Radio Resource Control (RRC) States As shown in FIG. 9, the terminal device 10 takes one of three radio resource control (RRC) states: RRC connected (RRC_CONNECTED), RRC inactive (RRC_INACTIVE), and RRC idle (RRC_IDLE).

[0083] The RRC connected (RRC_CONNECTED) state is a state in which a connection (RRC context) between the terminal device 10 and the base station device 20 is established, and the terminal device 10 transmits and receives radio signals to and from the base station device 20. In the RRC inactive (RRC_INACTIVE) state, the connection (RRC context) between the terminal device 10 and the base station device 20 is maintained, but the terminal device 10 does not transmit or receive radio signals to and from the base station device 20. In the RRC idle (RRC_IDLE) state, the connection (RRC context) between the terminal device 10 and the base station device 20 is released.

[0084] The power consumption of the terminal device 10 increases in the order of the RRC idle (RRC_IDLE) state, the RRC inactive (RRC_INACTIVE) state, and the RRC connected (RRC_CONNECTED) state.

[0085] 1.5 Discontinuous Reception (DRX) Discontinuous reception (DRX) is used as a technique for reducing power consumption of the terminal device 10. DRX can be applied to the terminal device 10 in the RRC idle state and the RRC connected state. DRX in the RRC connected state is called CDRX (Connected mode Discontinuous Reception).

[0086] As shown in FIG. 10 , when DRX is configured (or set), the terminal device 10 does not need to continuously monitor the PDCCH, but monitors the PDCCH only during a predetermined on-duration. That is, the on-duration may be a period during which the terminal device 10 waits to receive one or more PDCCHs (i.e., PDCCH(s)). For example, after waking up, the terminal device 10 may wait to receive one or more PDCCHs during the on-duration. Furthermore, if the terminal device 10 successfully decodes the PDCCH, the terminal device 10 may continue monitoring the PDCCH and start an inactivity timer. Here, the repetition of the on-duration (e.g., periodic repetition) may be set using a predetermined cycle (DRX cycle, DRX period).

[0087] In DRX in the RRC idle state, the terminal device 10, for example, intermittently monitors the PDCCH to receive a paging message that calls the terminal device 10. In CDRX, the terminal device 10, for example, intermittently monitors the PDCCH to receive resource allocation information (i.e., a DCI format used for scheduling the PDSCH and / or the PUSCH). In DRX, a configuration can also be adopted in which short DRX (Short DRX) with a shorter cycle is first performed, and then long DRX (Long DRX) with a longer cycle is performed.

[0088] Some or all of the DRX parameters used to configure DRX in the terminal device 10 may be transmitted from the base station device 20 to the terminal device 10 using an RRC message. That is, the base station device 20 may transmit an RRC message including some or all of the DRX parameters to the terminal device 10. Here, some or all of the DRX parameters may be set for a cell group including one or more serving cells. That is, the base station device 20 may set a cell group including one or more serving cells and set some or all of the DRX parameters for the set cell group. For example, the base station device 20 may transmit an RRC message including information for setting a cell group to the terminal device 10. Here, the cell group may be a cell group for setting MAC parameters. Furthermore, the cell group may be referred to as a master cell group and / or a secondary cell group. Furthermore, the cell group may be referred to as a DRX group.

[0089] The terminal device 10 receives an RRC message including some or all of the DRX parameters, and controls the DRX operation based on some or all of the DRX parameters. That is, the terminal device 10 can control the DRX operation for each cell group based on some or all of the DRX parameters. In particular, a DRX-Config IE, which is an example of an RRC information element (IE), may include some or all of the DRX parameters, and an RRCReconfiguration, which is an RRC message including the DRX-Config IE, may be transmitted from the base station device 20 to the terminal device 10. Some or all of the DRX parameters may be included in another IE.

[0090] Here, some of the DRX parameters may be set commonly to the cell groups, i.e., some of the DRX parameters may not be set for each cell group, but may be set as parameters common to one or more cell groups.

[0091] Examples of DRX parameters used to configure (or set) DRX in the terminal device 10 are shown below. Note that the DRX parameters may be referred to as a set of DRX parameters or information related to DRX. The DRX parameters set (in other words, specify, determine, or identify) DRX settings. For example, the DRX settings may include at least one of an on-duration, an inactivity timer, and / or a cycle (in other words, a DRX cycle or a DRX period).

[0092] An on-duration timer (drx-onDurationTimer) indicating the duration of the on-duration of the terminal device 10. This DRX parameter is used to set the value of the on-duration. For example, the drx-onDurationTimer may be used to set the duration at the start of the DRX cycle.

[0093] An inactivity timer (drx-InactivityTimer) indicating the period during which the terminal device 10 maintains the ON state after receiving the PDCCH (i.e., the period until it switches to the OFF state). This DRX parameter may correspond to the value of the inactivity timer. For example, the drx-InactivityTimer may be used to set the period after the reception of a PDCCH (i.e., a PDCCH occasion) indicating a new DL transmission and / or UL transmission.

[0094] - Cycle of on period in short DRX (for example, short cycle) (drx-ShortCycle) This DRX parameter may correspond to the cycle in short DRX (DRX cycle, DRX period).

[0095] A short cycle timer (drx-ShortCycleTimer) indicating the duration of short DRX. For example, a period following the short DRX cycle may be set in the terminal device 10 using the drx-ShortCycleTimer.

[0096] - A start offset (drx-LongCycleStartOffset) indicating the period of the on-duration in long DRX (e.g., long cycle) and / or the start position of DRX (e.g., subframe and / or slot). This DRX parameter may correspond to the cycle (DRX cycle or DRX period) in long DRX. For example, the start position of the long DRX cycle and / or short DRX cycle may be set using drx-LongCycleStartOffset.

[0097] - A slot offset (drx-SlotOffset) indicating the delay before the on-duration starts. For example, the drx-SlotOffset may be used to set the delay before the on-duration timer (drx-onDurationTimer) starts.

[0098] In normal DRX (including CDRX), the time arrangement of the on-period is specified by the system frame number (SFN) and subframe number. As mentioned above, one cycle of the system frame number is 10240 ms (= 10.24 seconds). When one cycle ends, the SFN returns to 0.

[0099] To introduce a longer time range into DRX, extended DRX (eDRX) can be applied. In eDRX, the time arrangement of the on-period is specified using the above-mentioned hyper system frame number in addition to the system frame number (SFN) and subframe number. As mentioned above, one period of the hyper system frame number is 10485.76 seconds (= approximately 2.91 hours), so a longer time range can be used in eDRX.

[0100] 1.6. 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 quality of service (QoS) requirements.

[0101] 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.

[0102] Video data is transmitted and received based on a frame rate expressed in frames per second (FPS). For example, one frame of data is transmitted and received every 16.67 ms at 60 FPS and every 8.33 ms at 120 FPS.

[0103] 1.7 XR Traffic Characteristics and DRX An XR-compatible terminal device 10 receives multiple data streams with different traffic characteristics. Note that "data stream(s)" can be expressed as a word(s) indicating a series of signals transmitted and received in time series, such as data flow(s), traffic, or traffic flows.

[0104] 11 , for example, the terminal device 10 receives multiple types of traffic, including data traffic arriving at a 10 ms interval, voice traffic arriving at a 20 ms interval, and video traffic arriving at a 16.67 ms interval. That is, each type of traffic has a different traffic period from the other types of traffic.

[0105] The multiple types of traffic may include various other traffic, such as intra-coded frames, which are key frames not based on prediction, and predicted frames, which are predicted based on intra-coded frames.

[0106] As described above, it is assumed that the terminal device 10 executes the above-described DRX in a case where multiple types of traffic arrive in parallel at the terminal device 10. While the DRX period is constant, multiple traffic types arrive at the terminal device 10 irregularly, as shown in FIG. 11 . Therefore, in order for the terminal device 10 to receive multiple traffic types without omission using only a single DRX setting (i.e., a set of DRX parameters), it becomes necessary to set the on-period of the terminal device 10 longer. As a result, a technical problem arises in that the power consumption of the terminal device 10 increases.

[0107] 1.8. Multiple Discontinuous Reception (DRX) Settings For the above reasons, multiple DRX settings are configured for the terminal device 10. In order to identify multiple DRX settings, a setting identifier may be set for each DRX setting. One DRX setting corresponds to, for example, one DRX-Config IE including multiple DRX parameters as shown in the above-mentioned section 1.5. As a DRX parameter, a setting identifier for identifying the DRX setting may be included in the DRX setting.

[0108] For example, DRX setting 1 corresponding to data traffic arriving at a 10 ms cycle, DRX setting 2 corresponding to voice traffic arriving at a 20 ms cycle, and DRX setting 3 corresponding to video traffic arriving at a 16.67 ms cycle may be set in the terminal device 10. For example, in DRX setting 1, the on-period cycle may be set to 10 ms, in DRX setting 2, the on-period cycle may be set to 20 ms, and in DRX setting 3, the on-period cycle may be set to 16.67 ms.

[0109] When multiple DRX settings are configured in the terminal device 10, the terminal device 10 monitors the PDCCH in an on-period specified by any of the DRX settings. Therefore, when the above-described DRX settings 1 to 3 are configured in the terminal device 10, the terminal device 10 monitors the PDCCH in an on-period specified by any of DRX setting 1, DRX setting 2, and DRX setting 3. Note that even in an on-period specified by multiple DRX settings, the terminal device 10 may perform a normal PDCCH monitoring operation.

[0110] In an XR application, it is assumed that the data stream or traffic to be received will fluctuate. For example, if a user of the terminal device 10 deactivates the video function, the terminal device 10 no longer needs to receive video traffic. Consequently, DRX settings corresponding to video traffic are no longer required.

[0111] If it is not possible to change each DRX setting individually, the terminal device 10 will perform unnecessary traffic reception operation (PDCCH monitoring) based on the unnecessary DRX setting, resulting in a technical problem of increased power consumption of the terminal device 10.

[0112] It is to be understood that the above technical problem is not limited to XR, but also occurs in other technologies that receive multiple data streams with different traffic characteristics.

[0113] 1.9. Terminal Device 10 Transmits Preference Information Regarding DRX Settings Therefore, the terminal device 10 of this embodiment is configured to transmit, for example, preference information regarding each of one or more discontinuous reception settings among a plurality of discontinuous reception settings set by the base station device 20 to the base station device 20 via the communication unit 120. For example, the terminal device 10 is configured to transmit, for one or more discontinuous reception settings among a plurality of discontinuous reception settings set by the base station device 20, preference information indicating whether the terminal device 10 uses one or more discontinuous reception settings to the base station device 20 via the communication unit 120. Note that processing by the processor 101 or the control unit 110 of the terminal device 10 may be simply described as processing by the terminal device 10. Furthermore, processing by the processor 201 or the control unit 210 of the base station device 20 may be simply described as processing by the base station device 20.

[0114] The above-mentioned phrase "indicating whether to use" encompasses "indicating use" and "indicating no use" throughout this application. "Using" may mean continuing to use the current setting, i.e., "maintaining." "Using" may mean using another setting in addition to the current setting, i.e., "addition." "Using" may mean ceasing the current setting and using another setting, i.e., "modification." "Using" may mean using a new setting, i.e., "requirement." "Not using" may mean ceasing to use the current setting, i.e., "release" or "deletion." Furthermore, "using" and "not using" may mean other similar or related words different from the above-mentioned words. For example, the preference information may be information indicating the terminal device 10's preferences regarding "use," "maintain," "addition," "modification," "requirement," "release," and / or "deletion" for each of one or more discontinuous reception settings. Furthermore, the preference information may be information indicating preferences in the terminal device 10 regarding "use," "maintain," "add," "change," "necessary," "release," and / or "delete" for each of one or more DRX parameters included in each of one or more discontinuous reception settings. Here, the one or more DRX parameters may be values ​​of one or more DRX parameters.

[0115] The word "send" used above encompasses similar concepts such as "notify," "provide," "transmit," and "carry" throughout this application.

[0116] The RRC messages described below may be the RRC messages described in Non-Patent Document 2 or may be newly defined RRC messages. The IEs included in the RRC messages described below may be the IEs described in Non-Patent Document 2 or may be newly defined IEs.

[0117] As shown in FIG. 12 , in step S1210, the terminal device 10 transmits a user equipment capability information (UECapabilityInformation) message including information indicating that multiple DRX configurations can be configured in the terminal device 10 to the base station device 20. The user equipment capability information message is generated by the terminal device 10. The information included in the user equipment capability information message may indicate that the terminal device 10 supports multiple DRX configurations (i.e., supports multiple DRX configurations), or may indicate the number of DRX configurations supported by the terminal device 10 (e.g., the maximum number). Instead of the user equipment capability information message, another RRC message may be used. For example, the terminal device 10 may transmit a user equipment capability information message including information indicating that it supports the configuration of multiple DRX configurations for a certain cell group to the base station device 20.

[0118] It should be noted that, if the terminal device 10 included in the communication system S supports a plurality of DRX settings by default, step S1210 may be omitted.

[0119] In step S1212, the base station device 20 configures base station side DRX settings corresponding to multiple DRX settings to be set for the terminal device 10 based on the user equipment capability information message (or other RRC message) received from the terminal device 10.

[0120] In step S1214, the base station device 20 transmits to the terminal device 10 an RRC reconfiguration message including information indicating multiple DRX configurations to be configured in the terminal device 10. For example, the base station device 20 may transmit to the terminal device 10 an RRC reconfiguration message including information indicating multiple DRX configurations for a certain cell group. That is, multiple DRX configurations may be configured for a certain cell group (i.e., each of the cell groups). The terminal device 10 may identify multiple DRX configurations for a certain cell group (i.e., each of the cell groups). The RRC reconfiguration message is generated by the base station device 20. A configuration identifier that identifies the DRX configuration may be assigned to each of the multiple DRX configurations. Priorities may be set for the multiple configuration identifiers. Another RRC message may be used instead of the RRC reconfiguration message.

[0121] Each of the multiple DRX settings includes one or more DRX parameters. The DRX parameters included in each DRX setting may include at least one of the on-duration timer (drx-onDurationTimer), the inactivity timer (drx-InactivityTimer), the long cycle and start offset (drx-LongCycleStartOffset), and the slot offset (drx-SlotOffset). The DRX parameters included in each DRX setting may also include a setting identifier that identifies the DRX setting. The DRX parameters included in each DRX setting are also referred to as individual DRX parameters. Here, the terminal device 10 may transmit preference information regarding each of the one or more DRX parameters included in each of the multiple DRX settings configured by the base station device 20 to the base station device 20.

[0122] Instead of or in addition to the setting identifier for each DRX setting described above, a parameter identifier for identifying each DRX parameter included in each DRX setting may be assigned to the DRX parameters.

[0123] There may be DRX parameters that are commonly set for multiple DRX settings. DRX parameters that are commonly set for multiple DRX settings are also referred to as common DRX parameters. For example, for a certain DRX parameter, a parameter included in a DRX setting assigned a setting identifier with the highest priority may be used commonly among multiple DRX settings. Furthermore, individual DRX parameters may overwrite common DRX parameters (in other words, shared parameters may be applied when individual DRX parameters are not set). On the other hand, even if individual DRX parameters are specified, common DRX parameters may take precedence. The priority of a DRX setting may be explicitly set as the priority of a setting identifier, or may be implicitly set based on at least one DRX parameter included in the DRX setting.

[0124] The multiple DRX settings may correspond to the multiple types of traffic described above, respectively. For example, as described above, the multiple DRX settings may include DRX setting 1 including a parameter for the period of an on-duration corresponding to data traffic, DRX setting 2 including a parameter for the period of an on-duration corresponding to voice traffic, and DRX setting 3 including a parameter for the period of an on-duration corresponding to video traffic. The above-mentioned on-durations may be different from each other.

[0125] In step S1214, the base station device 20 may transmit instruction information instructing the terminal device 10 to transmit preference information related to the DRX setting. The instruction information is generated by the base station device 20.

[0126] Here, the base station device 20 may transmit instruction information (hereinafter, first instruction information) instructing the terminal device 10 to transmit preference information related to one DRX setting. For example, the base station device 20 may transmit first instruction information instructing the terminal device 10 to transmit a user equipment auxiliary information message regarding preference information related to one DRX setting for one cell group. Based on reception of the first instruction information, the terminal device 10 may be considered to be configured to transmit preference information related to one DRX setting for one cell group (i.e., it may be expressed that the terminal device 10 is configured as described above).

[0127] Furthermore, the base station device 20 may transmit, to the terminal device 10, instruction information (hereinafter, second instruction information) instructing the terminal device 10 to transmit preference information related to multiple DRX settings. Here, the first instruction information and the second instruction information may be different information. For example, the base station device 20 may transmit, to the terminal device 10, second instruction information instructing the terminal device 10 to transmit a user equipment assistance information message regarding preference information related to multiple DRX settings (e.g., each of multiple DRX settings, each of multiple DRX parameters) for a certain cell group. Based on reception of the second instruction information, the terminal device 10 may be considered to be configured to transmit preference information related to multiple DRX settings for a certain cell group (i.e., it may be expressed that the terminal device 10 is configured as described above).

[0128] For example, the base station device 20 may transmit an RRC message including first instruction information and / or second instruction information to the terminal device 10. The terminal device 10 may transmit a user equipment assistance information message including preference information regarding one DRX setting for a certain cell group based on the first instruction information. Furthermore, the terminal device 10 may transmit a user equipment assistance information message including preference information regarding multiple DRX settings (e.g., each of multiple DRX settings, each of multiple DRX parameters) for a certain cell group based on the second instruction information.

[0129] The base station device 20 may transmit to the terminal device 10 a prohibit timer indicating a period during which the terminal device 10 is prohibited from (re)transmitting preference information. That is, the prohibit timer may be information regarding a timer for transmitting a user equipment assistance information message including preference information related to DRX settings. The prohibit timer is a timer that is triggered when the terminal device 10 transmits preference information. For example, the terminal device 10 may start a timer (i.e., a timer with a value indicated by the prohibit timer) when preference information for a certain cell group differs from the last transmitted preference information and the prohibit timer is not running. The above prohibit timers may be set for multiple DRX settings. For example, the base station device 20 may transmit an RRC message including a prohibit timer for each of the multiple DRX settings. Furthermore, the terminal device 10 may control the transmission of a user equipment assistance information message including preference information related to each of the multiple DRX settings based on the prohibit timer set for each of the multiple DRX settings. Furthermore, the prohibition timer may be set commonly for multiple DRX configurations. For example, the base station device 20 may transmit an RRC message including a prohibition timer (i.e., a common prohibition timer value) common to multiple DRX configurations. Furthermore, the terminal device 10 may control the transmission of a user equipment assistance information message including preference information for each of the multiple DRX configurations based on the prohibition timer set commonly for the multiple DRX configurations.

[0130] The above instruction information and / or prohibition timer may be included in the above-mentioned RRC reconfiguration message (or another RRC message) and transmitted from the base station device 20 to the terminal device 10. Furthermore, the above instruction information and / or prohibition timer may be transmitted from the base station device 20 to the terminal device 10 separately and in parallel with the above-mentioned RRC reconfiguration message (or another RRC message). When transmitted separately, the instruction information and / or prohibition timer may be transmitted in an RRC message or in a message of another layer (MAC CE, DCI, etc.).

[0131] In step S1216, the terminal device 10 configures one or more DRX settings in the terminal device 10 based on information indicating one or more DRX settings included in the RRC reconfiguration message (or another RRC message) transmitted from the base station device 20. Furthermore, the terminal device 10 monitors the PDCCH based on the one or more DRX settings (i.e., performs PDCCH monitoring in DRX operation). For example, the terminal device 10 may consider a time during which an on-duration timer (drx-onDurationTimer) or an inactivity timer (drx-InactivityTimer) is operating as the active time. Furthermore, the terminal device 10 may monitor the PDCCH during the active time. For example, the terminal device 10 may consider a time during which an on-duration timer (drx-onDurationTimer) or an inactivity timer (drx-InactivityTimer) set for a certain cell group is operating as the active time for a serving cell belonging to the certain cell group. Furthermore, when a certain cell group is in active time, the terminal device 10 may monitor the PDCCH in a serving cell belonging to the certain cell group.

[0132] Regarding this sequence diagram, unless step S1220 is reached, the terminal device 10 continues PDCCH monitoring in the DRX operation of step S1216.

[0133] As shown in FIG. 12 , in step S1220, the terminal device 10 determines that the conditions for transmitting preference information are satisfied. Examples of "conditions for transmitting preference information" are given below. The following conditions may be expressed, for example, as "conditions for making DRX setting unnecessary" or "conditions for making DRX setting necessary." - The terminal device 10 has stopped / started receiving traffic corresponding to the DRX setting (e.g., video traffic). - The power consumption per unit time of the terminal device 10 has exceeded / fallen below a predetermined threshold. - The remaining battery charge of the terminal device 10 has exceeded / fallen below a predetermined threshold. - The user has explicitly or implicitly instructed the terminal device 10 to transmit preference information. - The terminal device 10 has preferences for DRX settings. For example, the terminal device 10 has preferences for one or more DRX parameters included in each of a plurality of DRX settings.

[0134] In step S1222, the terminal device 10 transmits a user equipment assistance information (UEAssistanceInformation) message including preference information to the base station device 20 via the communication unit 120. The preference information may be information indicating whether the terminal device 10 uses one or more DRX settings among a plurality of DRX settings set in the terminal device 10 by the base station device 20. The preference information is generated by the terminal device 10. For example, when the terminal device 10 has preferences for one or more DRX parameters, the terminal device 10 may include the corresponding parameters in the preference information and set preferred values ​​for the parameters in the terminal device 10. As described above, the one or more DRX parameters may be included in each of a plurality of DRX settings and may be set for a certain cell group (i.e., each of the cell groups). Based on steps S1220 and S1222, this can be expressed as "the preference information indicates that the DRX setting corresponding to traffic determined to be unnecessary in the terminal device 10 will not be used" or "the preference information indicates that the DRX setting corresponding to traffic determined to be necessary in the terminal device 10 will be used."

[0135] Any information structure capable of indicating "whether or not one or more DRX settings are to be used" may be used as the preference information. For example, a bit string may be used as the preference information, or a setting identifier and / or a parameter identifier of the DRX setting may be used.

[0136] In a case where the preference information is represented by a bit string, one bit may indicate whether or not one DRX setting is used. For example, if the bit string starts from 0 and the setting identifier of the DRX setting starts from 1, the i-th bit may correspond to the i+1-th DRX setting. That is, the i-th bit in the preference information may indicate a preference for the DRX setting assigned the i+1 setting identifier. In the bit string, "0" may indicate "use of DRX setting," and "1" may indicate "do not use DRX setting." The length of the bit string of the preference information (i.e., the number of bits of the preference information) may be fixed or variable. For example, the length of the bit string of the preference information may be determined based on the number of DRX settings configured for the terminal device 10. Furthermore, for example, the length of the bit string of the preference information may be determined based on the setting identifier (e.g., the value of the setting identifier) ​​of the DRX setting configured for the terminal device 10. As an example, the fixed number of bits of the preference information may be equal to or greater than the maximum number of DRX settings that can be set for the terminal device 10, and more preferably equal to the maximum number. For example, the length of the bit string of the preference information may be equal to the number of DRX settings that can be set for the terminal device 10.

[0137] In a case where a setting identifier is used in the preference information, for example, a setting identifier indicating a DRX setting whose usage state the terminal device 10 wishes to change and information indicating the usage state requested by the terminal device 10 (e.g., maintain or release) may be included in the preference information as a pair. That is, the terminal device 10 may include a setting identifier indicating a DRX setting and a preference for the DRX setting (and / or each of one or more DRX parameters included in the DRX setting) in the preference information. Preferences corresponding to each of multiple DRX settings may be included in the preference information. Furthermore, with regard to adding a DRX setting, a setting identifier indicating a DRX setting to be added to the terminal device 10 (i.e., to be newly used) may be included in the preference information.

[0138] In a case where a parameter identifier is used in the preference information, for example, a parameter identifier indicating a DRX parameter in the DRX setting that the terminal device 10 wants to change and a parameter value requested by the terminal device 10 may be included in the preference information as a pair. That is, the terminal device 10 may include a parameter identifier indicating a DRX parameter and a preference for the DRX parameter in the preference information. Preferences corresponding to each of a plurality of DRX parameters may be included in the preference information. Furthermore, with regard to adding a DRX parameter, a parameter identifier indicating a DRX parameter to be added to the terminal device 10 (i.e., to be newly used) may be included in the preference information.

[0139] The preference information may be transmitted from the terminal device 10 to the base station device 20 in various messages or signals. As described above, a user equipment assistance information message, which is an RRC message, may include preference information corresponding to multiple DRX settings, and the terminal device 10 may transmit the user equipment assistance information message to the base station device 20. The preference information may be a DRX-Preference IE included in UEAssistanceInformation, or may be a newly defined IE. Furthermore, the preference information may be carried in another RRC message and transmitted from the terminal device 10 to the base station device 20.

[0140] Alternatively, the preference information may be transmitted from the terminal device 10 to the base station device 20 in a layer other than the RRC layer. The preference information may be transmitted in an uplink MAC CE or in a UCI.

[0141] In step S1224, the base station device 20 configures, in the base station device 20, DRX settings on the base station side corresponding to the multiple DRX settings to be set for the terminal device 10, based on the preference information included in the user equipment auxiliary information message (or another RRC message) received from the terminal device 10. For example, the base station device 20 configures the base station device 20 so as to release the "unused" DRX setting indicated in the received preference information.

[0142] In step S1226, the base station device 20 transmits an RRC reconfiguration message (or another RRC message) including information indicating multiple DRX settings to the terminal device 10. For example, the base station device 20 determines one or more DRX settings based on preference information received from the terminal device 10, and transmits an RRC reconfiguration message including information indicating the determined one or more DRX settings to the terminal device 10. For example, the base station device 20 includes information indicating that the "unused" DRX setting indicated in the preference information received from the terminal device 10 will be released in the RRC reconfiguration message to be transmitted to the terminal device 10.

[0143] In step S1228, the terminal device 10 configures a plurality of DRX settings in the terminal device 10 based on the plurality of DRX settings included in the RRC reconfiguration message (or another RRC message). Subsequently, the terminal device 10 monitors the PDCCH based on the configured plurality of DRX settings (i.e., performs PDCCH monitoring in DRX operation). That is, the terminal device 10 monitors the PDCCH during active time.

[0144] According to the above configuration, the terminal device 10 transmits preference information indicating whether or not to use one or more DRX settings to the base station device 20. That is, the terminal device 10 transmits preference information regarding each of one or more DRX settings to the base station device 20. Furthermore, the terminal device 10 transmits preference information regarding each of one or more DRX parameters included in each of the multiple DRX settings to the base station device 20. Therefore, it is possible to notify the base station device 20 of whether or not a DRX setting is required in the terminal device 10 for each DRX setting. As a result, for example, it is possible to release only unnecessary DRX settings from among the multiple DRX settings, thereby achieving both reduced power consumption and appropriate DRX operation. Furthermore, as a result, for example, it is possible to maintain or add only necessary DRX settings, making it possible to perform appropriate DRX operation while suppressing an increase in power consumption.

[0145] 2.1. 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 scope of equivalents. Other combinations including one or more elements included in the above embodiment are also within the scope and spirit of the present disclosure.

[0146] 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).

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 2.2 Supplementary Notes Some or all of the above embodiments and modified examples may be described as, but are not limited to, the following supplementary notes. Below, relationships are expressed in which a supplementary note that is subordinate to multiple supplementary notes is subordinate to another supplementary note that is subordinate to multiple supplementary notes. All of the following dependency relationships of supplementary notes are included in the above embodiments.

[0151] (Supplementary Note 1) A terminal device (10) comprising: a control unit (110); and a communication unit (120) configured to perform wireless communication by being controlled by the control unit, wherein the control unit is configured to transmit preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set by a base station device (20) to the base station device via the communication unit.

[0152] (Supplementary Note 2) The terminal device according to Supplementary Note 1, wherein each of the plurality of discontinuous reception settings set in the terminal device includes a plurality of discontinuous reception parameters.

[0153] (Supplementary Note 3) The terminal device according to Supplementary Note 2, wherein a common discontinuous reception parameter is set as the discontinuous reception parameter that is used in common among the plurality of discontinuous reception settings.

[0154] (Supplementary Note 4) The terminal device according to Supplementary Note 2 or 3, wherein the preference information includes one or more parameter identifiers that identify the plurality of discontinuous reception parameters.

[0155] (Supplementary Note 5) The terminal device according to any one of Supplementary Notes 1 to 4, wherein the preference information includes one or more setting identifiers that identify the plurality of discontinuous reception settings.

[0156] (Supplementary Note 6) The terminal device according to Supplementary Note 5, wherein the preference information includes information indicating whether or not to use a discontinuous reception setting corresponding to each of the one or more setting identifiers.

[0157] (Supplementary Note 7) The terminal device according to any one of Supplementary Notes 1 to 4, wherein the preference information is a bit string including a plurality of bits corresponding to the plurality of discontinuous reception settings, and each of the plurality of bits indicates whether or not to use the plurality of discontinuous reception settings.

[0158] (Supplementary Note 8) The terminal device according to any one of Supplementary Notes 1 to 7, wherein a prohibition timer indicating a period during which retransmission of the preference information is prohibited is set for each of the plurality of discontinuous reception settings.

[0159] (Supplementary Note 9) The terminal device according to any one of Supplementary Notes 1 to 8, wherein the communication unit is configured to transmit and receive a plurality of types of traffic, and the plurality of discontinuous reception settings correspond to the plurality of types of traffic, respectively.

[0160] (Supplementary Note 10) The terminal device according to Supplementary Note 9, wherein the plurality of discontinuous reception settings have different on-period cycles corresponding to the plurality of types of traffic.

[0161] (Supplementary Note 11) The terminal device according to Supplementary Note 9 or 10, wherein the control unit is configured to transmit to the base station device the preference information indicating that the terminal device will not use a discontinuous reception setting corresponding to traffic determined to be unnecessary.

[0162] (Supplementary Note 12) The terminal device according to any one of Supplementary Notes 1 to 11, wherein the control unit is configured to transmit capability information indicating that the plurality of discontinuous reception settings can be set in the terminal device to the base station device via the communication unit.

[0163] (Supplementary Note 13) The terminal device according to Supplementary Note 12, wherein the capability information indicates a maximum number of the plurality of discontinuous reception settings supported by the terminal device.

[0164] (Supplementary Note 14) A base station device (20) comprising: a control unit (210); and a communication unit (220) configured to perform wireless communication by being controlled by the control unit, wherein the control unit is configured to receive, from the terminal device via the communication unit, preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set for the terminal device.

[0165] (Supplementary Note 15) A method comprising: in a terminal device, generating preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set by a base station device; and transmitting the preference information to the base station device.

[0166] (Supplementary Note 16) A communication system (S) comprising a terminal device and a base station device which communicate wirelessly with each other, wherein the terminal device (10) transmits preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set by the base station device (20) to the base station device via a communication unit.

[0167] (Supplementary Note 17) A program that causes a terminal device (10) to execute the following: generating preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set by a base station device (20); and transmitting the preference information to the base station device.

[0168] (Supplementary Note 18) A non-transient tangible recording medium having recorded thereon a program that causes a terminal device (10) to execute the following: generating preference information indicating whether or not the terminal device will use one or more discontinuous reception settings out of a plurality of discontinuous reception settings that can be set by a base station device (20); and transmitting the preference information to the base station device.

Claims

1. A terminal device (10), A control unit (110); A transmission unit (121) that transmits a user equipment auxiliary information message including auxiliary information for setting a value of a discontinuous reception (DRX) cycle corresponding to traffic having a period of a non-integer value to a base station device (20); a receiving unit (122) for receiving from the base station device a radio resource control (RRC) reconfiguration message including a DRX configuration including information indicating a value of the discontinuous reception cycle and information indicating a value of an on-duration timer; The receiving unit is receiving an RRC reconfiguration message from the base station device, the RRC reconfiguration message including information for setting a timer value for transmitting the auxiliary information; The control unit is Controlling to transmit the user equipment assistance information message including the assistance information to the base station device based on the information for setting a value of the timer for transmitting the assistance information; and controlling to monitor a physical downlink control channel during an active time based on the information indicating a value of the discontinuous reception cycle and the information indicating a value of the on-duration timer. Terminal device.

2. The control unit: When the auxiliary information included in the user equipment auxiliary information message is different from the last transmitted auxiliary information and the timer for transmitting the auxiliary information is not running, the timer for transmitting the auxiliary information is started. The terminal device according to claim 1 .

3. The receiving unit, receiving an RRC reconfiguration message including information for setting to transmit the auxiliary information from the base station device; The control unit is When the base station device is set to transmit the auxiliary information, the base station device controls the user equipment auxiliary information message including the auxiliary information to be transmitted to the base station device. The terminal device according to claim 1 or 2.

4. A base station device (20), A control unit (210); A receiving unit (222) for receiving a user equipment assistance information message including assistance information for setting a value of a discontinuous reception (DRX) cycle corresponding to traffic having a period of a non-integer value from a terminal device (10); A transmission unit (221) that transmits a radio resource control (RRC) reconfiguration message including a DRX configuration including information indicating a value of the discontinuous reception cycle and information indicating a value of an on-duration timer to the terminal device, The transmission unit is Transmitting an RRC reconfiguration message to the terminal device, the RRC reconfiguration message including information for setting a timer value for transmitting the auxiliary information; The control unit is Controlling to receive, from the terminal device, the user equipment assistance information message including the assistance information based on the information for setting a value of the timer for transmitting the assistance information; and controlling the terminal device to monitor a physical downlink control channel during an active time based on the information indicating a value of the discontinuous reception cycle and the information indicating a value of the on-duration timer. Base station equipment.

5. The timer for the transmission of the auxiliary information is started when the auxiliary information included in the user equipment auxiliary information message is different from the last transmitted auxiliary information and the timer for the transmission of the auxiliary information is not running. The base station device according to claim 4.

6. The transmission unit, receiving an RRC reconfiguration message including information for setting to transmit the auxiliary information from the base station device; The control unit is When the auxiliary information is set to be transmitted, the user equipment auxiliary information message including the auxiliary information is received from the terminal device. The base station device according to claim 4 or 5.

7. A communication method for a terminal device (10), comprising: Transmitting a user equipment assistance information message including assistance information for setting a value of a discontinuous reception (DRX) cycle corresponding to traffic having a non-integer value period to a base station device (20); receiving, from the base station device, a radio resource control (RRC) reconfiguration message including a DRX configuration including information indicating a value of the discontinuous reception cycle and information indicating a value of an on-duration timer; receiving an RRC reconfiguration message from the base station device, the RRC reconfiguration message including information for setting a value of a timer for transmitting the auxiliary information; Controlling to transmit the user equipment assistance information message including the assistance information to the base station device based on the information for setting a value of the timer for transmitting the assistance information; controlling to monitor a physical downlink control channel during an active time based on the information indicating a value of the discontinuous reception cycle and the information indicating a value of the on-duration timer; A communication method comprising:

8. The timer for the transmission of the auxiliary information is started when the auxiliary information included in the user equipment auxiliary information message is different from the last transmitted auxiliary information and the timer for the transmission of the auxiliary information is not running. The communication method according to claim 7.

9. Receiving an RRC reconfiguration message from the base station device, the RRC reconfiguration message including information for configuring the base station device to transmit the auxiliary information; When the base station is configured to transmit the auxiliary information, the base station transmits the user equipment auxiliary information message including the auxiliary information to the base station; 9. The communication method according to claim 7 or 8, comprising: