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

Abstract

Efficiency of power saving related to wireless communication between a terminal device and a base-station device is improved. The terminal device includes a receiving portion, a processing portion, and a transmitting portion. The receiving portion receives setting information of a first active period indicating a transmission / reception period of a cell unit from the base-station device and a second active period indicating a transmission / reception period for each terminal device. When a scheduling request for requesting an uplink resource is transmitted, the processing portion determines a control method of the scheduling request on the basis of a priority of a service that triggers the scheduling request, timing when the scheduling request is triggered, information of the first active period, information indicating a predetermined period counted from the triggered timing, and a setting state of a resource of a physical-uplink control channel for transmitting the scheduling request. The transmission portion transmits the scheduling request on the basis of the determination by the processing portion.

Description

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

[0001] The present invention relates to a terminal device, a base station device, a method for controlling a terminal device, and a method for controlling a base station device.

[0002] The standardization project 3GPP (3rd Generation Partnership Project (registered trademark)) is studying technical specifications for communication standards that meet the requirements of NR (New Radio (also referred to as "5G")), which is the fifth generation of mobile communications, including eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communication).

[0003] In 3GPP, NES (Network Energy Savings) technology is being studied to reduce power consumption on the network side (that is, base station devices and core network devices) (Non-Patent Document 1).

[0004] One of the technologies under study for NES is Cell DTX / DRX, which is intended to realize discontinuous reception (DRX) and / or discontinuous transmission (DTX) on a cell-by-cell basis. Cell DTX / DRX is a technology in which a base station device sets an active period and an inactive period (or non-active period) on a cell-by-cell basis, and the base station device transmits and receives only during the active period and restricts transmission and reception during the inactive period, thereby reducing power consumption (Non-Patent Documents 1 and 2).

[0005] 3GPP TR 38.864 V18.0.0 (2022-12) R2-2310685

[0006] By applying Cell DTX / DRX, a base station device can achieve power saving effects, but if unexpected data transmission / reception occurs and scheduling is not completed within the Cell DTX / DRX active period, transmission / reception of the remaining data must wait for scheduling in the next active period. This causes a problem that, for example, if the generated data is highly instantaneous data, the service quality (QoS (Quality of Service)) requirements cannot be met, resulting in a degradation of the user experience.

[0007] In particular, Non-Patent Document 2 discloses a method for requesting uplink resources by using a random access procedure even during a Cell DTX / DRX inactive period when a service that should be handled with priority, such as an emergency call, is about to be initiated. However, although an emergency call can occur even during a Cell DTX / DRX inactive period, Non-Patent Document 2 has a problem in that it is unclear how to request uplink resources when an emergency call occurs during a Cell DTX / DRX active period. Furthermore, it is necessary to newly define the operation after using the random access procedure based on the status of the terminal device and the base station device, but Non-Patent Document 2 does not mention any solution to these problems.

[0008] An object of one aspect of the present invention is to improve the efficiency of power saving related to wireless communication between a terminal device and a base station device when applying network power reduction techniques without affecting high priority services.

[0009] A terminal device according to one aspect of the present invention includes a receiving unit that receives, from a base station device, configuration information of a first active period indicating a transmission and reception period on a cell-by-cell basis and a second active period indicating a transmission and reception period for each terminal device; a processing unit that, when transmitting a scheduling request requesting uplink resources, determines a control method for the scheduling request based on the priority of the service that triggers the scheduling request, the timing at which the scheduling request is triggered, information about the first active period, information indicating a predetermined period measured from the triggering timing, and a configuration state of resources of a physical uplink control channel for transmitting the scheduling request; and a transmitting unit that transmits the scheduling request based on the determination of the processing unit.

[0010] A control method for a base station device includes a transmitter that transmits to a terminal device setting information for a first active period indicating a transmission / reception period on a cell-by-cell basis and a second active period indicating a transmission / reception period for each terminal device; a processor that sets information for the first active period, information indicating a predetermined period measured from a trigger timing, and physical uplink control channel resources for transmitting the scheduling request, in order to allow the terminal device to determine a control method for a scheduling request requesting uplink resources corresponding to a high-priority service; and a receiver that receives the scheduling request transmitted based on the determination of the terminal device.

[0011] According to the above-described aspect, when applying network power reduction technology, it is possible to improve the efficiency of power saving related to wireless communication between a terminal device and a base station device without affecting high-priority services.

[0012] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of the functional configuration of a terminal device according to an embodiment. FIG. 3 is a diagram illustrating an example of the functional configuration of a base station device according to an embodiment. FIG. 4 is a diagram illustrating an example of a method for transmitting a scheduling request when Cell DRX is configured. FIG. 5 is a diagram illustrating another example of a method for transmitting a scheduling request when Cell DRX is configured. FIG. 6 is a diagram illustrating an example of a procedure for configuring Cell DTX and Cell DRX. FIG. 7 is a diagram illustrating an example of a method for controlling active periods and inactive periods of a terminal device. FIG. 8 is a diagram illustrating a conventional method for transmitting a scheduling request when Cell DRX is configured. FIG. 9 is a diagram illustrating an example of the hardware configuration of a terminal device.

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The problems and embodiments in this specification are merely examples and do not limit the scope of the present invention. In particular, even if the expressions used are different, the technology of the present invention can be applied as long as they are technically equivalent, and do not limit the scope of the present invention. Furthermore, each embodiment can be appropriately combined within the scope of the processing content. For example, an inactive period may be referred to as an inactive period.

[0014] Publicly known technologies may be used as appropriate in the wireless communication system according to the embodiment of the present invention. Applicable publicly known technologies may be, for example, 5G (NR), Beyond 5G, 5G-Advanced, or other wireless communication methods. The wireless communication system according to the embodiment of the present invention targets NR, but is not limited thereto. For example, the embodiment of the present invention can also be applied to LTE (Long Term Evolution) and LTE-Advanced. It can also be applied to a wireless communication system that uses NR as part of the wireless communication system.

[0015] Furthermore, the embodiments of the present invention are applicable to any wireless communication system including at least a terminal device and a base station device, and are also applicable to future wireless communication systems. In the following description, LTE and LTE-Advanced are also referred to as E-UTRA (Evolved Universal Terrestrial Radio Access), but the meaning is the same.

[0016] Hereinafter, embodiments of a base station apparatus, a terminal apparatus, and a wireless communication system disclosed in the present application will be described with reference to the drawings. Note that the disclosed technology is not limited to the following embodiments.

[0017] <Wireless Communication System> Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 1 according to an embodiment of the present invention. The wireless communication system 1 according to the embodiment is configured from, for example, a terminal device 10, base station devices 20A and 20B, and a core network 30. Note that when there is no need to distinguish between the base station devices 20A and 20B, they will simply be referred to as base station device 20. Furthermore, there may be multiple terminal devices 10.

[0018] The terminal device 10 may be a wireless terminal such as a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a tablet, a wearable device, a personal computer, a vehicle, or any other device or equipment (sensor device, etc.) having a wireless communication function. The terminal device 10 may also be referred to as a wireless communication device, a communication device, a receiving device, a mobile station, a UE (User Equipment), a user device, etc.

[0019] A wireless communication service is provided to a terminal device 10 by a base station device 20 and a core network 30 in a wireless communication system 1. The core network 30 has functions such as managing service subscriber information, managing sessions such as voice calls, and managing location registration of the terminal device 10. The core network 30 also transmits control data and / or user data to the terminal device 10 via the base station device 20.

[0020] The core network 30 may be a 5G Core (5GC) in 5G (NR) or an Evolved Packet Core (EPC) in 4G (E-UTRA). The connection method between the core network 30 and the base station device 20 may be a Non-Stand Alone (NSA) method or a Stand Alone (SA) method.

[0021] The 5G base station device 20 connected to the 5GC is a gNB, and the 4G base station device 20 connected to the EPC is an eNB. The 5G base station devices are connected to each other via an Xn interface, and the 4G base station devices are connected to each other via an X2 interface.

[0022] An area (coverage area) formed by a base station device 20 may be called a "cell." E-UTRA and 5G are cellular communication systems constructed by multiple cells. As a wireless communication system according to an embodiment of the present invention, either a time division duplex (TDD) or a frequency division duplex (FDD) method may be applied, and different methods may be applied to each cell.

[0023] The base station device 20 may be configured, for example, as being divided into a CU (Centralized Unit), a DU (Distributed Unit), and an RU (Radio Unit). The CU is connected to a core network. The DU is connected to the terminal device 10 via the RU, for example. The communication path between the CU and the DU is realized by, for example, a fronthaul interface (F1 interface). Multiple DUs may be connected to one CU.

[0024] In the example shown in Figure 1, data (DL data, downlink data) transmitted from the core network 30 to the terminal device 10 is transmitted from the core network 30 to the base station device 20, and then transmitted (forwarded) from the base station device 20 to the terminal device 10.

[0025] Data (UL data, uplink data) transmitted from the terminal device 10 to the core network 30 is transmitted from the terminal device 10 to the base station device 20 and then transmitted (transferred) from the base station device 20 to the core network 30 .

[0026] The terminal device 10 and the base station device 20 transmit and receive RRC messages (also called RRC signaling) in a Radio Resource Control (RRC) layer. Also, the terminal device 10 and the base station device 20 transmit and receive MAC control elements (MAC CEs) in a Medium Access Control (MAC) layer.

[0027] The RRC message is transmitted as an RRC Protocol Data Unit (PDU), and the logical channel (LCH) to which it is mapped may be a common control channel (CCCH), a dedicated control channel (DCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), or a multicast control channel (MCCH).

[0028] The MAC CE is transmitted as a MAC PDU (or MAC subPDU). A MAC subPDU is equivalent to a service data unit (SDU) in the MAC layer plus, for example, 8 bits of header information, and the MAC PDU includes one or more MAC subPDUs.

[0029] Next, as physical channels and physical signals according to the embodiment, there are at least a synchronization signal (Primary Synchronization Signal, Secondary Synchronization Signal), a physical broadcast channel (PBCH: Physical Broadcast Channel), a physical random access channel (PRACH: Physical Random Access Channel), a physical downlink control channel (PDCCH: Physical Downlink Control Channel), a channel state information reference signal (CSI-RS: Channel State Information-Reference Signal), a physical uplink control channel (PUCCH: Physical Uplink Control Channel), a physical downlink shared channel (PDSCH: Physical Downlink Shared Channel), a physical uplink shared channel (PUSCH: Physical Uplink Shared Channel), a scheduling reference signal (SRS: Scheduling Reference Signal), and a demodulation reference signal (DMRS), but detailed description thereof will be omitted.

[0030] <Terminal Device> Fig. 2 is a diagram showing an example of the functional configuration of the terminal device 10 according to the embodiment. As shown in Fig. 2, the terminal device 10 includes, for example, a processing unit 11, a control unit 13, a receiving unit 15, a transmitting unit 17, and a transmitting / receiving antenna unit 19. The processing unit 11 includes, for example, a radio resource processing unit 111 and an intermittent transmission / reception processing unit 113. Note that the functional configuration of the terminal device 10 shown in Fig. 2 is merely an example, and the functional divisions and names of each functional block may be different as long as the operations according to the embodiment can be performed. Furthermore, one or more blocks that realize other functions may be present.

[0031] The processing unit 11 generates, for example, control information for controlling the receiving unit 15 and the transmitting unit 17, and outputs the control information to the control unit 13. The processing unit 11 executes processes related to, for example, a radio resource control layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control layer.

[0032] The radio resource processing unit 111 manages various setting information (RRC parameters, information elements (IEs)) of the terminal device 10. For example, the radio resource processing unit 111 generates information to be allocated to each channel of the physical uplink and outputs the information to the transmission unit 17. Furthermore, based on instructions from the base station device 20, the radio resource processing unit 111 performs measurements of the serving cell and surrounding cells, start and stop of transmission and reception processing, DL synchronization procedure (cell search), UL synchronization procedure (random access procedure), reacquisition of system information, event evaluation related to handover, a series of processes related to handover, and the like.

[0033] The discontinuous transmission and reception processing unit 113 performs a series of control processes related to discontinuous reception (DRX) and discontinuous transmission (DTX). For example, the discontinuous transmission and reception processing unit 113 manages multiple timers related to discontinuous reception (DRX) and discontinuous transmission (DTX), and performs a series of transmission and reception processes for the terminal device 10 during active periods or inactive periods, based on instructions from the radio resource processing unit 111 or instructions from the base station device 20. The discontinuous transmission and reception processing unit 113 particularly controls timers related to Cell DTX / DRX related to discontinuous transmission and reception of the base station device 20 and timers related to DRX (C-DRX: Connected mode DRX) related to discontinuous transmission and reception of the connected terminal device 10, and performs determination processes related to transmission of the terminal device 10 based on the relationship between transmission opportunities for scheduling requests and active periods of Cell DTX / DRX.

[0034] The control unit 13 performs various controls in the terminal device 10. For example, the control unit 13 generates control signals or control data for controlling the receiving unit 15 and the transmitting unit 17 based on control information from the processing unit 11. Furthermore, the control unit 13 controls uplink transmission to the base station device 20, scheduling request transmission, and downlink reception from the base station device 20 based on determination information regarding discontinuous transmission and reception from the discontinuous transmission and reception processing unit 113.

[0035] The receiving unit 15 separates, demodulates, and decodes various signals received from the base station device 20 via the transmitting / receiving antenna unit 19 based on a control signal provided by the control unit 13. The receiving unit 15 outputs the decoded information to the processing unit 11.

[0036] The transmitter 17 generates, for example, a physical uplink signal based on a control signal provided from the controller 13, and performs encoding and modulation on the physical uplink signal or the physical uplink channel provided from the processor 11. The transmitter 17 multiplexes various signals and transmits them to the base station device 20 via the transmitter-receiver antenna unit 19.

[0037] The processing unit 11 and the control unit 13 are realized, for example, by a processor system including a processor and a memory. In this case, the processor provides the functions of the processing unit 11 and the control unit 13 by executing a program that describes the operation of the terminal device 10, which will be described later. The processing unit 11 and the control unit 13 may be realized by a single processor system or by multiple processor systems. Alternatively, the processing unit 11 and the control unit 13 may be realized by a DSP (Digital Signal Processor), a hardware circuit, or the like.

[0038] <Base Station Device> Fig. 3 is a diagram showing an example of the functional configuration of the base station device 20 according to the embodiment. As shown in Fig. 3, the base station device 20 includes, for example, a processing unit 21, a control unit 23, a receiving unit 25, a transmitting unit 27, and a transmitting / receiving antenna unit 29. The processing unit 21 illustratively includes a radio resource processing unit 211 and an intermittent transmission / reception processing unit 213. Note that the functional configuration of the base station device 20 shown in Fig. 3 is merely an example, and the names of the functional divisions and functional blocks may be different as long as the operations according to the embodiment can be performed. Furthermore, one or more blocks that realize other functions may be present.

[0039] The processing unit 21 generates, for example, control information for controlling the receiving unit 25 and the transmitting unit 27, and outputs the control information to the control unit 23. The processing unit 21 executes processes relating to, for example, the radio resource control layer, the packet data integration protocol layer, the radio link control layer, and the medium access control layer.

[0040] The radio resource processing unit 211 generates, for example, downlink data, an RRC message, and a MAC control element to be allocated to the physical downlink shared channel PDSCH, and outputs these to the transmission unit 27. The radio resource processing unit 211 also generates a control signal or control data to be allocated to the physical downlink control channel PDCCH, and outputs this to the transmission unit 27. Furthermore, the radio resource processing unit 211 manages various setting information of the terminal device 10. Based on a signal from the terminal device 10 or a notification by an RRC message, the radio resource processing unit 211 executes start and stop of transmission and reception processing, start of a UL synchronization procedure (random access procedure), update of system information, adjustment of the beam transmission angle, cell setting related to handover, and pre-setting of parameters related to measurement event types (measurement event identifiers).

[0041] The discontinuous transmission / reception processing unit 213 performs a series of control processes related to discontinuous reception (DRX) and discontinuous transmission (DTX). For example, based on instructions from the radio resource processing unit 211 or notifications by signals or RRC messages from the terminal device 10, the discontinuous transmission / reception processing unit 213 manages multiple timers related to discontinuous reception (DRX) and discontinuous transmission (DTX), and performs a series of transmission / reception processes for the base station device 20 during active periods or inactive periods. In particular, the discontinuous transmission / reception processing unit 213 generates timers related to Cell DTX / DRX related to discontinuous transmission / reception of the base station device 20, timers related to C-DRX related to discontinuous transmission / reception of the connected terminal device 10, and timers related to retransmission control, controls adjustment between these timers, and performs reception processes for the terminal device 10 based on the correspondence between transmission opportunities for scheduling requests and active periods of Cell DTX / DRX, and determines the response thereto.

[0042] The control unit 23 performs various controls in the base station device 20. For example, the control unit 23 generates control signals or control data for controlling the receiving unit 25 and the transmitting unit 27 based on control information from the processing unit 21. Furthermore, the control unit 23 controls downlink transmission to the terminal device 10 and uplink reception from the terminal device 10 based on determination information regarding discontinuous transmission and reception from the discontinuous transmission and reception processing unit 213.

[0043] The receiving unit 25 separates, demodulates, and decodes various signals received from the terminal device 10 or the core network 30 via the transmitting / receiving antenna unit 29 based on a control signal provided by the control unit 23. The receiving unit 25 outputs the decoded information to the processing unit 21.

[0044] The transmitter 27 generates, for example, a downlink reference signal based on the control signal provided by the controller 23. The transmitter 27 encodes, modulates, multiplexes, and so on various pieces of information provided by the processor 21, and transmits the signal to the terminal device 10 via the transmitting / receiving antenna unit 29.

[0045] Furthermore, the transmitter 27 transmits data to the terminal device 10, another base station device 20, or the core network 30. The receiver 25 receives data from the terminal device 10, another base station device 20, or the core network 30.

[0046] The processing unit 21 and the control unit 23 are realized, for example, by a processor system including a processor and a memory. In this case, the processor provides the functions of the processing unit 21 and the control unit 23 by executing a program that describes the operation of the base station device 20, which will be described later. The processing unit 21 and the control unit 23 may be realized by a single processor system or by multiple processor systems. Alternatively, the processing unit 21 and the control unit 23 may be realized by a DSP, a hardware circuit, or the like.

[0047] <Scheduling Request> The terminal device 10 initiates a scheduling request (SR) procedure to request uplink resources (UL-SCH: UL Shared channel) for new transmission from the base station device 20. The physical channel used for the scheduling request is either the PUCCH or the PRACH. A scheduling request configuration (scheduling request configuration, SR configuration) is configured for each MAC entity of the terminal device 10. The scheduling request configuration may include information on PUCCH resources related to one or more SR transmissions. Furthermore, the scheduling request configuration corresponds to one or more logical channels (LCHs). That is, the terminal device 10 transmits an SR using a scheduling request configuration corresponding to the LCH of the uplink data to be transmitted.

[0048] LCH information is set for each terminal device 10 by LCH configuration, and the LCH configuration includes at least a priority, an LCH group to be mapped, and an identifier (ID) of a corresponding scheduling request. The MAC entity of the terminal device 10 determines an appropriate SR transmission occasion based on the scheduling request configuration.

[0049] The base station device 20 uses an RRC message to configure one or more scheduling request settings for the terminal device 10, each of which includes at least the following information: (1) SR prohibition timer (sr-ProhibitTimer): timer information that starts after an SR is transmitted using the PUCCH and indicates the time for which SR transmission is prohibited (i.e., indicates the time from the time of SR transmission until the next SR transmission is permitted), (2) SR maximum transmission count (sr-TransMax): indicates the maximum number of triggered SR transmissions that are permitted, and when the number of SR transmissions per LCH reaches the maximum SR transmission count, the terminal device 10 releases PUCCH resources and clears the uplink grant and downlink assignment, and starts a random access procedure.

[0050] The terminal device 10 has a different SR prohibition timer and a different maximum number of SR transmissions set for each SR setting, and has an SR transmission counter as an internal variable for managing the number of SR transmissions for each SR setting. Every time the terminal device 10 instructs a lower layer to transmit an SR, it increments the corresponding SR transmission counter and simultaneously starts the corresponding SR prohibition timer.

[0051] When the terminal device 10 detects an untransmitted (pending) uplink buffer in the PDCP / RLC layer, it triggers an SR in the MAC layer (MAC entity). The SR is triggered on an LCH basis. When an SR is triggered, the terminal device 10 considers the SR to be pending until the SR is canceled. Furthermore, when a MAC PDU including a Buffer Status Report MAC CE (BSR MAC CE) is transmitted or when uplink resources equal to or greater than the total amount of all pending uplink data are allocated, the terminal device 10 cancels all pending SRs and stops the corresponding SR prohibition timers.

[0052] When a DRX (C-DRX (described later)) that is set for each terminal device 10 is configured, the terminal device 10 transmits an SR using a PUCCH, and when the SR is in a pending state, the DRX (C-DRX) of the terminal device 10 is considered to be in an active period.

[0053] Alternatively, the terminal device 10 may trigger SR in the MAC layer (MAC entity) to transmit MAC header information corresponding to a MAC CE (BFR MAC CE) for beam failure recovery to the base station device 20.

[0054] Conventional connected DRX (C-DRX: Connected mode DRX, UE DRX) will be described using Fig. 8 . Fig. 8 is a diagram showing an example of a method for controlling an active period and an inactive period of a terminal device 10. Note that the horizontal axis indicates the passage of time. The active period indicates a period (section, time) during which the terminal device 10 monitors the PDCCH. In other words, it indicates a monitoring period during which the terminal device 10 attempts to decode a PDCCH scrambled (data masked) with a predetermined RNTI (Radio Network Temporary Identifier). The RNTI that the terminal device 10 attempts to decode is any one of C-RNTI, CI-RNTI, CS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, TPC-SRS-RNTI, AI-RNTI, SL-RNTI, SLCS-RNTI, and SL Semi-Persistent Scheduling V-RNTI.

[0055] When connecting (accessing) to the base station device 20, the terminal device 10 acquires a synchronization signal / physical broadcast channel block (SS / PBCH Block) and adjusts downlink synchronization using the SSB. The SSB includes a synchronization signal and a physical broadcast channel (PBCH). The synchronization signal is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). The base station device 20 may transmit the SSB even during an inactive period.

[0056] The cell quality (reception quality) is calculated by measuring the synchronization signal block (SSB) or the channel state information reference signal (CSI-RS). The cell quality can be expressed using any of the following: Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Received Signal Strength Indicator (RSSI), Signal to Interference plus Noise Ratio (SINR), and path loss.

[0057] The terminal device 10 adjusts uplink synchronization using an individual timing advance (TA). The individual timing advance is individually notified by the base station device 20 via a random access response in the random access procedure. Uplink synchronization is considered valid while the timing advance timer (TA Timer) is counting. The random access procedure is initiated by the terminal device 10 transmitting a physical random access channel (PRACH). The terminal device 10 may consider the counting period of a timer (contention resolution timer) related to the fourth procedure (contention resolution, message 4) of the random access procedure as the C-DRX active period.

[0058] Furthermore, the terminal device 10 stops periodic or quasi-periodic uplink transmission during the inactive period. Specifically, the terminal device 10 stops reporting of a sounding reference signal (SRS) and channel state information (CSI) during the inactive period.

[0059] 8 is configured with at least an offset indicating the start position of an active period (C-DRX active period, C-DRX active time), a duration timer indicating the length of the active period, and a DRX cycle indicating the DRX repetition period by the base station device 20. These pieces of configuration information are configured as DRX-related parameters from the base station device 20 to the terminal device 10 using an RRC message.

[0060] As shown in FIG. 8 , the active period of C-DRX starts from the timing (time T00) when an offset time from a certain frame has elapsed. The terminal device 10 starts timing a duration timer (drx-onDurationTimer) from time T00, and considers the active period to be in progress while the duration timer is timing. Furthermore, if the physical downlink control channel PDCCH is received while the duration timer is timing and the PDCCH indicates notification of new data, the terminal device 10 starts timing an inactivity timer (drx-InactivityTimer (Inactivity timer in the figure)). The terminal device 10 performs transmission and reception as if the inactivity timer is also in progress during timing. In other words, the terminal device 10 considers the active period of C-DRX to be extended.

[0061] Time T01 indicates the timing when the terminal device 10 receives a PDCCH indicating notification of new data. At this time, the terminal device 10 starts counting an inactivity timer and continues monitoring the PDCCH. Time T02 indicates that the terminal device 10 receives a PDCCH indicating notification of new data again before the inactivity timer expires. At this time, the terminal device 10 restarts the inactivity timer that is currently counting at time T02. Time T03 indicates the timing when the inactivity timer that was restarted at time T02 expires.

[0062] The terminal device 10 considers the C-DRX active period to have expired at time T03 when the inactivity timer expires, and transitions to an inactive period (C-DRX inactive period, C-DRX inactive time).

[0063] 9 is a diagram showing an example of a method for transmitting a scheduling request by the terminal device 10 when Cell DRX is set, in which the horizontal axis indicates the passage of time.

[0064] As shown in Fig. 9 , a cell-based DRX active period (Cell DRX active period) starts at the timing (time T10) when an offset time (offset2) from a certain frame has elapsed. The terminal device 10 and the base station device 20 start timing a cell active period duration timer (cell dtx / drx-onDurationTimer) from time T10, and consider the cell active period duration timer to be timing as a Cell DRX active period. Furthermore, the terminal device 10 and the base station device 20 consider the cell active period duration timer to have expired (not timing) (time T11) as a Cell DRX inactive period.

[0065] Time T12 indicates the timing when the terminal device 10 starts a service that is given priority (hereinafter referred to as a high-priority service), such as an emergency call or a public safety service, or detects the service. Any method may be used for the terminal device 10 to detect a service that is given priority. For example, the terminal device 10 may detect (determine, analyze) the type of the service based on a notification from the application layer or the NAS layer.

[0066] Next, the terminal device 10 determines whether the next active period will start within a predetermined period (Duration 1) from time T12. If the active period of Cell DRX does not start within the predetermined period (Duration 1) from time T12 to time T13, the terminal device 10 exceptionally transmits a scheduling request (SR) to notify the start of a high-priority service such as an emergency call even during an inactive period of Cell DRX.

[0067] 9, it is assumed that a PRACH resource for transmitting a PRACH is allocated at time T14 (i.e., a PRACH transmission opportunity (PRACH occasion) is set), and a PUCCH resource for transmitting an SR is allocated at time T15. Here, it is assumed that the PUCCH resource at time T15 is within the active period of Cell DRX.

[0068] At this time, the terminal device 10 determines that the time interval until the next active period is sufficiently far away because the PUCCH resource (time T15) is allocated after time T13, and determines that it is OK to start a random access procedure for a scheduling request (SR) using the PRACH resource (time T14) within the inactive period of Cell DRX, without waiting until the PUCCH resource (time T15).

[0069] The base station device 20 receives the PRACH transmitted using the PRACH resource (time T14) during the inactive period of Cell DRX, and transmits a random access response (RAR) in response to the PRACH. The terminal device 10 transmits data related to a priority service such as an emergency call using an uplink resource (PUSCH resource) indicated by an uplink grant (UL grant) included in the RAR.

[0070] Hereinafter, when there is no need to distinguish between Cell DTX and Cell DRX, they will be referred to as Cell DTX / DRX.

[0071] The terminal device 10 may be specified, by RRC, a search space in which to monitor a PDCCH that instructs activation / deactivation (application / non-application) of Cell DTX / DRX from the base station device 20. The PDCCH that instructs activation / deactivation of Cell DTX / DRX may be scrambled by a Cell DTX / DRX RNTI (cellDTXDRX-RNTI). The base station device 20 notifies the terminal device 10 of the cellDTXDRX-RNTI as part of the Cell DTX / DRX configuration. The base station device 20 may specify the cellDTXDRX-RNTI and its search space for each cell to indicate to the terminal device 10 that a PDCCH that instructs activation / deactivation of Cell DTX / DRX is used within the cell.

[0072] When the terminal device 10 receives a PDCCH including information indicating activation of Cell DTX or Cell DRX while Cell DTX / DRX is inactive (not applied), the terminal device 10 activates Cell DTX or Cell DRX based on the Cell DTX / DRX setting in the specified cell. Similarly, when the terminal device 10 receives a PDCCH including information indicating deactivation of Cell DTX or Cell DRX while Cell DTX / DRX is active (applied), the terminal device 10 deactivates Cell DTX or Cell DRX based on the Cell DTX / DRX setting in the specified cell.

[0073] <Conditional Handover> A terminal device 10 in a communication state moves within a cell formed by a base station device 20 using handover or conditional handover (CHO). In conditional handover, cell setting information specifying a candidate cell (target cell) as a handover destination and a trigger condition for handover (conditional handover) (measurement event type (measurement event, measurement report event)) are notified to the terminal device 10 in advance from the base station device 20. The measurement event (trigger condition) specified in the conditional handover setting is also referred to as an event condition (Conditional Event).

[0074] At this time, the base station device 20 can configure a maximum of eight candidate cells (i.e., a maximum of eight candidate cell configurations) for the terminal device 10. The terminal device 10 measures the serving cell and neighboring cells. Furthermore, the terminal device 10 evaluates measurement events based on trigger conditions notified from the base station device 20. Hereinafter, one or more pieces of cell configuration information and trigger conditions are collectively referred to as a conditional handover configuration. The conditional handover configuration includes candidate cells and other necessary cell configurations, and is specified in the form of one or more lists. Here, the measurement target cell is a candidate cell included in the conditional handover configuration, and is identified by a physical cell identifier (PCI). In other words, the terminal device 10 considers a cell having a physical cell identifier specified in an RRC message (RRCReconfiguration) included in the conditional handover configuration to be the measurement target cell.

[0075] Taking the above into consideration, the following embodiments of the present invention will be described with reference to the drawings. In the description of the embodiments of the present invention, if a specific description of well-known functions or configurations related to the embodiments of the present invention makes the gist of the embodiments of the present invention unclear, the detailed description will be omitted.

[0076] 4 to 6 show an example of a method for controlling scheduling requests during an active period and an inactive period of the terminal device 10 and the base station device 20 according to the first embodiment, with the horizontal axis indicating the passage of time. The PDCCH (or RNTI) monitored by the terminal device 10 during the active period may be the same as in the past unless otherwise specified. Furthermore, the uplink signals and uplink channels that the terminal device 10 stops transmitting during the inactive period are at least the same signals / channels as in the past.

[0077] The terminal devices 10 in Figures 4 to 6 are configured with at least an offset indicating the start position of the active period (C-DRX active period) for each terminal device 10 from the base station device 20, a duration timer indicating the length of the active period, and a DRX cycle indicating the repetition period (not shown).

[0078] Furthermore, as parameters indicating cell-based DTX (Cell DTX, a period during which transmission to the terminal apparatus 10 is possible) or cell-based DRX (Cell DRX, a period during which transmission from the terminal apparatus 10 is possible), at least a subframe-based offset (offset2) indicating the start position of the cell active period (Cell DTX active period, or Cell DRX active period), a cell active period duration timer (Cell DTX on duration timer, or Cell DRX on duration timer) indicating the length of the Cell DTX or Cell DRX active period, and a Cell DTX cycle or Cell DRX cycle (Cell DTX cycle, or Cell DRX cycle) indicating the repetition period are set. Furthermore, a slot-based offset (slotOffset) may be further set for the offset (offset2) indicating the start position of the cell active period (not shown). These setting information are set as Cell DTX / DRX related parameters (CellDTXDRX-Config) from the base station apparatus 20 to the terminal apparatus 10 using an RRC message.

[0079] Here, the active period of cell-based DRX is an example of a first active period, and the active period of C-DRX is an example of a second active period.

[0080] Furthermore, timer information indicating the predetermined period used to determine whether to transmit an SR may be individually set by the base station device 20 to the terminal device 10 using an RRC message, may be set for each cell using system information (SIB), or may be predefined as a fixed value (e.g., 256 frames or 3 seconds). The predetermined period may be a value calculated from the active or inactive period of Cell DTX / DRX. The base station device 20 may set a value such as twice the period, the same period, half the period, or one-third the period, and may calculate the predetermined period from existing base parameters in the terminal device 10. Examples of existing parameters include the active or inactive period of Cell DTX, the active or inactive period of Cell DRX, the SR transmission cycle, the SR prohibition timer, the random access response window (or message B response window), and the contention resolution timer. The base station device 20 may individually set for the terminal device 10 which existing parameters to use as a base. The RRC message is, for example, an RRC Reconfiguration message.

[0081] FIG. 4 is a diagram showing an example of a method for transmitting a scheduling request related to a high-priority service in the terminal device 10 when Cell DRX is set.

[0082] As in FIG. 9 , the cell-based DRX active period starts at the timing (time T40) when an offset time (offset2) from a certain frame has elapsed. The terminal device 10 and the base station device 20 start timing the cell active period duration timer (cell dtx / drx-onDurationTimer) from time T40, and consider the cell active period duration timer to be counting as a cell DRX active period. Furthermore, the terminal device 10 and the base station device 20 consider the cell DRX inactive period to be when the cell active period duration timer expires (is not counting) (time T41). Time T42 indicates the start timing of the cell-based DRX active period in the next cycle (cell DRX cycle).

[0083] Time T43 indicates the timing when the terminal device 10 starts a high-priority service or detects the service. That is, at least one SR is pending at time T43. The terminal device 10 determines whether the next Cell DRX active period will start within a predetermined period (Duration 1) from time T43. A high-priority service is, for example, a service that requires a QoS equal to or higher than a predetermined level, or a service in which a high-priority PDU session (an Emergency PDU session in the case of an emergency call, or a Mission critical service session in the case of public safety) is established. That is, the terminal device 10 determines whether the next Cell DRX active period (time T42) will start within the predetermined period (Duration 1) from time T43 to time T44. The predetermined period (Duration 1) may also be referred to as a time interval, a time distance, or the like.

[0084] High-priority services are mapped to high-priority LCHs. As a mapping method, for example, the highest-priority LCH may be selected from the priorities of the LCHs set in the terminal device 10, the highest-priority LCH within a predetermined period may be selected, any LCH with a priority equal to or higher than a certain level may be selected, or an LCH other than a low-priority LCH may be selected. The base station device 20 may set information indicating a priority equal to or higher than a certain level in the terminal device 10.

[0085] 4, it is assumed that the terminal device 10 is assigned a PRACH resource for transmitting a PRACH at time T45, and a PUCCH resource (D-SR) for transmitting an SR at time T46, by the base station device 20. Here, it is assumed that the PRACH resource at time T45 is within an inactive period of Cell DRX, and the PUCCH resource at time T46 is within an active period of Cell DRX.

[0086] If the next active period of Cell DRX starts within a predetermined period (that is, between time T43 and time T44), the terminal device 10 further makes the following determination.

[0087] If one or more PUCCH resources used for SR transmission are allocated before time T44, and the priorities of the LCHs corresponding to the respective PUCCH resources are all low-priority (in other words, if all of the priorities of the LCHs corresponding to the respective PUCCH resources do not correspond to high-priority services), the terminal device 10 performs SR using a PRACH resource instead of SR using a PUCCH resource. In other words, the terminal device 10 determines that it is acceptable to select a PRACH resource (time T45) within the Cell DRX inactive period and start a random access procedure related to a scheduling request (SR) without waiting until the PUCCH resource (time T46). The terminal device 10 starts the random access procedure and cancels all pending SRs. The terminal device 10 starts the random access procedure in a primary cell in a primary cell group or a primary-secondary cell in a secondary cell group. In addition, the terminal device 10 can determine whether the SR corresponds to a high-priority service by, for example, determining whether the priority of the LCH corresponding to the PUCCH resource used for SR transmission is higher than or equal to the priority of the high-priority service.

[0088] On the other hand, if one or more PUCCH resources used for SR transmission are allocated before time T44 and at least one of the LCH priorities corresponding to the respective PUCCH resources is high priority, the terminal device 10 performs SR transmission using the PUCCH resource. In other words, the terminal device 10 does not perform a random access procedure using the PRACH resource (time T45), but selects a PUCCH resource (time T46) within the Cell DRX active period and determines that it is OK to transmit a scheduling request (SR).

[0089] In short, the terminal device 10 determines whether to transmit a PRACH at time T45, for example, according to the first priority of the data (or the LCH corresponding to the data) generated at time T43 and the second priority of the LCH corresponding to the PUCCH resource used to transmit an SR at time T46. Therefore, for example, the terminal device 10 controls so that an SR is transmitted at time T46 when the first priority is equal to or lower than the second priority, and so that a PRACH is transmitted at time T45 when the first priority is higher than the second priority. Note that, if there are multiple PUCCH resources by time T44, the terminal device 10 may, for example, set the highest priority among the priorities of the LCHs corresponding to each of the multiple PUCCH resources as the second priority.

[0090] If the next Cell DRX active period does not start within a predetermined period, the terminal device 10 is permitted to request uplink resources based on a random access procedure to start a high-priority service even during a Cell DRX inactive period.

[0091] The method of determining whether the priority of an LCH is high priority or low priority may be such that priority information is explicitly set by the base station device 20 to the terminal device 10 in an RRC message as part of the LCH setting or SR setting, or a threshold value for determining the priority may be set, or the determination may be made based on the implementation of the terminal device 10.

[0092] For a random access procedure triggered based on a high-priority service, the terminal device 10 may initiate the random access procedure using dedicated random access resources, if configured in advance, including the random access preamble and the frequency-time resource of the PRACH.

[0093] The control method of FIG. 4 can also be expressed as follows using Equation 1:

[0094] [Formula 1] [(SFN×10)+(subframe number)+Duration1] modulo (Cell DRX cycle) < [(Offset2)+(SR offset)] module (Cell DRX cycle)

[0095] SFN (System Frame Number) and subframe number respectively indicate the system frame number and subframe number of the serving cell at the time of calculating Equation 1. SR offset indicates the cycle of the PUCCH resource for SR and the offset from the beginning of the subframe. Duration1, Cell DRX cycle, Offset2, and SR offset are specified in subframe units.

[0096] It should be noted that a control method that does not take the SR offset into consideration may also be used, in which case Equation 2 may be used.

[0097] [Formula 2] [(SFN×10)+(subframe number)+Duration1] modulo (Cell DRX cycle) < (Offset2)

[0098] When at least one SR is pending, the terminal device 10 performs the following determination for each pending SR: When a pending SR is triggered corresponding to a high-priority service, the cell DRX setting is enabled (activated), and the cell DRX is in an inactive period, the terminal device 10 starts a random access procedure if Equation 1 (or Equation 2) is satisfied.

[0099] If Formula 1 (or Formula 2) is not satisfied, the terminal device 10 maintains the pending SR until the Cell DRX active period, and during the Cell DRX inactive period, it determines not to notify (instruct) the lower layer that there is a pending SR, not to start the SR prohibit timer, and not to increment the SR transmission counter. Then, the terminal device 10 performs SR transmission using the PUCCH resource corresponding to each pending SR during the next Cell DRX active period.

[0100] FIG. 5 is a diagram showing another example of a method for transmitting a scheduling request related to a high-priority service in the terminal device 10 when Cell DRX is set.

[0101] As in FIG. 4 , the cell-based DRX active period starts at the timing (time T50) when an offset time (offset2) from a certain frame has elapsed. The terminal device 10 and the base station device 20 start timing the cell active period duration timer (cell dtx / drx-onDurationTimer) from time T50, and consider the cell active period duration timer to be counting as a cell DRX active period. Furthermore, the terminal device 10 and the base station device 20 consider the cell DRX inactive period to be when the cell active period duration timer expires (is not counting) (time T51). Time T52 indicates the start timing of the cell-based DRX active period in the next cycle (cell DRX cycle).

[0102] Time T53 indicates the timing at which the terminal device 10 starts a high-priority service or detects the service. That is, at time T53, at least one SR is pending. The terminal device 10 determines whether the next Cell DRX active period will start within a predetermined period (Duration 1) from time T53. That is, the terminal device 10 determines whether the next Cell DRX active period (time T52) will start between time T53 and time T54, when the predetermined period (Duration 1) has elapsed. The predetermined period (Duration 1) may also be referred to as a time interval, a time distance, or the like.

[0103] 5 , it is assumed that the terminal device 10 is assigned a PRACH resource for transmitting a PRACH at time T55 and a PUCCH resource for transmitting an SR at time T56 by the base station device 20. Here, it is assumed that the PRACH resource at time T55 and the PUCCH resource at time T56 are within the active period of Cell DRX.

[0104] When at least one SR is pending, the terminal device 10 makes the following determination for each pending SR: When a pending SR is triggered in response to a high-priority service, the Cell DRX setting is enabled (activated), and the Cell DRX is in an active period, the terminal device 10 further makes the following determination.

[0105] If one or more PUCCH resources used for SR transmission are allocated during the current Cell DRX active period (between time T53 and time T51) and the priorities of the LCHs corresponding to the respective PUCCH resources are all low priority, the terminal device 10 performs SR using a PRACH resource instead of SR using a PUCCH resource. In other words, if there is a PRACH resource (time T55) allocated earlier than the PUCCH resource (time T56), the terminal device 10 determines that it is acceptable to select the PRACH resource and transmit a scheduling request (SR). The terminal device 10 starts a random access procedure and cancels all pending SRs.

[0106] On the other hand, if one or more PUCCH resources used for SR transmission are allocated within the current Cell DRX active period, and at least one of the LCH priorities corresponding to the respective PUCCH resources is high priority, the terminal device 10 performs SR transmission using the PUCCH resource. In other words, the terminal device 10 does not perform a random access procedure using the PRACH resource (time T55) allocated earlier than the PUCCH resource (time T56), and determines that it is OK to select the PUCCH resource (time T56) within the Cell DRX active period and transmit a scheduling request (SR).

[0107] Alternatively, if one or more PUCCH resources used for SR transmission within the current Cell DRX active period are unavailable (invalid), the terminal device 10 performs SR transmission using the PRACH resource. The terminal device 10 initiates a random access procedure and cancels all pending SRs.

[0108] A case where a PUCCH resource is unavailable indicates a state where at least one of the following conditions is satisfied: (1) SR configuration using the PUCCH resource has not been notified, (2) an SR transmission opportunity using the PUCCH resource does not exist within the Cell DRX active period, (3) the PUCCH resource is unavailable due to an SR prohibition timer, (4) uplink synchronization is lost (the timing advance timer is not timing), or (5) the number of transmissions of the corresponding SR has reached the maximum number of transmissions. In other words, if none of the above conditions (1) to (5) is satisfied, the terminal device 10 considers that a valid PUCCH resource is configured.

[0109] FIG. 6 is a diagram showing an example of a method for transmitting a scheduling request related to a high-priority service in consideration of an SR transmission prohibition timer in the terminal device 10 when Cell DRX is set.

[0110] As in FIG. 4 , the cell-based DRX active period starts at the timing (time T60) when an offset time (offset2) from a certain frame has elapsed. The terminal device 10 and the base station device 20 start timing the cell active period duration timer (cell dtx / drx-onDurationTimer) from time T60, and consider the cell active period duration timer to be counting as a cell DRX active period. Furthermore, the terminal device 10 and the base station device 20 consider the cell DRX inactive period to be when the cell active period duration timer expires (is not counting) (time T61). Time T62 indicates the start timing of the cell-based DRX active period in the next cycle (cell DRX cycle).

[0111] Time T63 indicates the timing when the terminal device 10 starts a high-priority service or detects the service. As shown in Fig. 6, it is assumed that the base station device 20 allocates the PUCCH resource for SR transmission to the terminal device 10 at time T64 and allocates the PRACH resource for PRACH transmission to the terminal device 10 at time T67. Here, it is assumed that the PUCCH resource at time T64 is within the active period of Cell DRX, and the PRACH resource at time T67 is within the inactive period of Cell DRX. It is expected that the PUCCH resource for SR transmission at time T64 is a high-priority LCH, but it may also be a low-priority LCH.

[0112] If the terminal device 10 determines that the PUCCH resource for SR transmission is available, it transmits the SR to the base station device 20 using the PUCCH resource, and then starts counting the SR prohibition timer (time T64).

[0113] 6 , if the timing (time T65) at which the SR prohibition timer expires is within the Cell DRX inactive period, the terminal device 10 determines whether the next Cell DRX active period will start within a predetermined period (Duration 1) from time T65. That is, the terminal device 10 determines whether the next Cell DRX active period (time T62) will start within the predetermined period (Duration 1) from time T65 to time T66.

[0114] If the next Cell DRX active period does not start within a predetermined period, the terminal device 10 is permitted to request uplink resources based on the random access procedure to start a high-priority service even during a Cell DRX inactive period. For example, the terminal device 10 can use the PRACH resource (time T67) during the Cell DRX inactive period.

[0115] If the next Cell DRX active period starts within a predetermined period, the method of selecting a PUCCH resource for SR transmission, further taking into consideration the priority of the LCH, may be the same as that shown in FIG.

[0116] The control method of FIG. 6 can also be expressed as follows using Equation 1 (or Equation 2):

[0117] When at least one SR is pending, the terminal device 10 makes the following determination for each pending SR: When a pending SR is triggered corresponding to a high-priority service, (a) the Cell DRX setting is enabled (activated) and the Cell DRX is active, and (b) there is an available PUCCH resource for SR transmission, and the SR prohibition timer is not timing at the SR transmission timing, the terminal device 10 instructs a lower layer to transmit an SR using the PUCCH resource corresponding to the pending SR, and starts timing of the corresponding SR prohibition timer.

[0118] On the other hand, during the Cell DRX inactive period, the terminal device 10 starts a random access procedure if Formula 1 (or Formula 2) is satisfied, and maintains the pending SR until the Cell DRX active period begins if Formula 1 (or Formula 2) is not satisfied, and determines not to notify (instruct) a lower layer that there is a pending SR during the Cell DRX inactive period, not to start the SR prohibit timer, and not to increment the SR transmission counter.Then, the terminal device 10 performs SR transmission using the PUCCH resource corresponding to each pending SR during the next Cell DRX active period.

[0119] In the above description, when the terminal device 10 initiates a random access procedure to request uplink resources for a high-priority service, the terminal device 10 may regard the timing period of the random access response window (or message B response window) after transmitting a PRACH (random access preamble) as a C-DRX activation period, and may start monitoring at least the RA-RNTI (Random Access Radio Network Temporary Identifier: Random Access-RNTI) and the C-RNTI (Cell Radio Network Temporary Identifier: Cell-RNTI) during timing of the random access response window, as well as start monitoring a PDCCH (cellDTXDRX-RNTI, Cell DTX / DRX-RNTI) that instructs activation / deactivation of Cell DTX / DRX.

[0120] Furthermore, when the terminal device 10 initiates a random access procedure to request uplink resources for a high-priority service, the terminal device 10 may regard the counting period of a contention resolution timer (Contention resolution timer) after transmitting a PUSCH (i.e., RACH message 3) on the uplink resources indicated by the uplink grant included in the RAR as the C-DRX active period or the Cell DTX active period, and may start monitoring a PDCCH (cellDTXDRX-RNTI) that instructs activation / deactivation of Cell DTX / DRX in addition to monitoring at least the C-RNTI during the counting of the contention resolution timer.

[0121] Furthermore, if the random access is successful, that is, if the terminal device 10 successfully decodes the PDCCH scrambled with the C-RNTI while the contention resolution timer is timing, and the received PDCCH indicates a new transmission, the terminal device 10 may regard the period after the PDCCH is received as an active period of C-DRX or an active period of Cell DTX (or Cell DRX).

[0122] The terminal device 10 may use the information about the predetermined period to determine whether the next Cell DRX active period will start within the predetermined period again after the random access procedure is completed, or may perform the determination again when the random access procedure is not successful and a retry is performed (i.e., when the random access preamble is retransmitted).

[0123] After starting the random access procedure, if a PUCCH resource becomes valid before receiving an RAR, that is, if a PUCCH resource used for SR transmission becomes valid during the timing period of the random access response window (or message B response window), the terminal device 10 may select the PUCCH resource to transmit the SR. Furthermore, if a PUCCH resource becomes valid before receiving contention resolution, the terminal device 10 may select the PUCCH resource to transmit the SR.

[0124] When the terminal device 10 initiates a random access procedure to request uplink resources for a high-priority service, it transmits at least a C-RNTI (C-RNTI MAC CE) included in the RACH message 3. When the RACH message 3 includes a C-RNTI (C-RNTI MAC CE), the base station device 20 identifies (identifies, distinguishes) the terminal device 10 in the cell by the C-RNTI, and determines that the identified terminal device 10 has initiated a random access procedure for a scheduling request.

[0125] In the case of CA (Carrier Aggregation), that is, when Cell DRX is configured for multiple serving cells and all of them are in an active Cell DRX period, the terminal device 10 determines whether a valid PUCCH resource is configured within a predetermined period in a serving cell to which a scheduling request can be transmitted.

[0126] The base station device 20 may not set a predetermined period for the terminal device 10 (absent) or may set the period to a value indicating zero or infinity, thereby implicitly notifying the terminal device 10 that it will not allow the start of a random access procedure even if PUCCH resources corresponding to a high priority service are not available.

[0127] Furthermore, the terminal device 1 may determine whether to start the random access procedure based on information indicating support for emergency calls (IMS emergency support: ims-EmergencySupport) notified in the system information of the serving cell. That is, if ims-EmergencySupport indicates true, the terminal device 1 may determine that the start of the random access procedure is permitted.

[0128] Note that Cell DTX and Cell DRX may be set with the same parameters (active period, cycle, offset), in which case Cell DRX can be read as Cell DTX / DRX.

[0129] As described above, according to the first embodiment, the terminal device 10 and the base station device 20 are able to appropriately transmit high-priority scheduling requests based on the active / inactive periods of Cell DRX even in a cell to which Cell DTX / DRX is applied for power saving, and therefore are able to efficiently transmit and receive data while suppressing an increase in power consumption of the base station device 20.

[0130] Second Embodiment A second embodiment will be described. Note that a description of configurations, functions, or procedures common to the first and second embodiments will be omitted. In other words, the following mainly describes the differences from the first embodiment.

[0131] 7 is a sequence diagram showing an example of a setting procedure related to Cell DTX / DRX setting (configuration) in the terminal device 10 and the base station device 20. Although not shown, the procedure starts from a state in which the wireless connection (RRC setup) procedure between the terminal device 10 and the base station device 20 is completed and the state of the terminal device 10 has transitioned to a communicating state (connected state, also referred to as an RRC Connected state). Also, it is assumed that the terminal device 10 generates an RRC message (UE Capability message) and transmits it to the base station device 20 to notify the base station device 20 of its own wireless capabilities.

[0132] The base station device 20 transmits a first RRC message (RRC message 1 in the figure) to the terminal device 10 (step S100). The first RRC message is an individual RRC message, such as an RRC Reconfiguration message. The first RRC message includes at least a Cell DTX / DRX duration timer, a Cell DTX / DRX offset, and a Cell DTX / DRX cycle as the Cell DTX / DRX settings for the cell. The terminal device 10 that has received the Cell DTX / DRX settings retains the settings, enables the received settings according to instructions from the base station device 20, and applies them in transmission and reception processing.

[0133] In addition, an additional identifier for determining whether to enable the Cell DTX / DRX setting at the same time as the Cell DTX / DRX setting may be included. Multiple Cell DTX / DRX settings may be set at the same time, or may be notified in a list format that allows settings to be added, deleted (released), and updated (Add, Release, Modify). When notified in list format, an index number for specifying each list may be notified.

[0134] The base station device 20 may generate only either the Cell DTX setting or the Cell DRX setting and notify the terminal device 10. The Cell DTX setting and the Cell DRX setting may be set independently, or the Cell DTX setting and the Cell DRX setting may be set in a linked manner.

[0135] In response to the first RRC message, the terminal device 10 transmits a second RRC message (RRC message 2 in the figure) to the base station device 20 (step S101). The second RRC message is, for example, an RRCReconfigurationComplete message.

[0136] After configuring the Cell DTX / DRX setting, the base station device 20 may dynamically instruct activation or deactivation of the setting depending on the traffic volume, the number of connected terminal devices 10, etc. In this case, an L1 message (L1 message in the figure) may be used as the instruction signal (step S102). The base station device 20 may instruct using a PDCCH common to multiple terminal devices 10 (i.e., a PDCCH scrambled with cellDTXDRX-RNTI).

[0137] When a common PDCCH is used, some of the DCI (Downlink Control Information) bits in the PDCCH may be used to specify the index of a cell for which both or either one of Cell DTX / DRX is to be activated or deactivated. The cellDTXDRX-RNTI may be common to all terminal devices 10 in a cell, or may be common to terminal devices 10 belonging to a predetermined group. The group classification may be notified in advance by an RRC message. Furthermore, a group of terminal devices 10 may be specified using some of the DCI bits. The base station device 20 may transmit at least the cellDTXDRX-RNTI, information on the search space (PDCCH transmission position) for receiving the common PDCCH, and the bit size of the DCI in the first message.

[0138] Alternatively, the base station device 20 may notify information instructing the trigger of a conditional handover by using another DCI bit in addition to the activation and deactivation of the setting in the L1 message of step S102. The conditional handover setting is set from the base station device 20 to the terminal device 10 by using an RRC message (e.g., an RRCReconfiguration message) before the L1 message is transmitted.

[0139] At this time, the conditional handover setting includes at least a conditional handover setting that takes the NES mode into consideration (hereinafter referred to as the NES mode CHO setting), and although an evaluation of events based on the NES mode CHO setting is performed until the L1 message is received, the conditional event is not satisfied and the handover itself is not performed. The base station device 20 specifies an instruction to enable the conditional event for the conditional handover either for each terminal device 10, for each terminal device 10 belonging to a predetermined group, or for each terminal device 10 within the cell.

[0140] When the Cell DRX setting is released, the terminal device 10 may delete the NES mode CHO setting or may stop evaluating events based on the NES mode CHO setting.The base station device 20 may notify the terminal device 10 of which bit in the DCI an instruction to enable a conditional handover condition event is transmitted in a bitmap format or by specifying the relative position of the bit based on the MSB (or LSB).

[0141] Here, consider the case where activation or deactivation of both or either of Cell DTX / DRX is instructed by an L1 message after SR transmission has been performed.

[0142] In the case of SR transmission by random access, if Cell DRX is activated at least while waiting for reception of an RAR or while waiting for reception of a contention resolution, and if a valid PUCCH resource is in a Cell DRX active period, the terminal device 10 performs SR transmission using the PUCCH resource at the next SR transmission opportunity. The terminal device 10 may determine that a PUCCH resource is valid when any PUCCH resource is configured, or may determine that a PUCCH resource is valid when there is a PUCCH resource corresponding to a high-priority LCH.

[0143] In the case of SR transmission via PUCCH, if at least Cell DRX is activated while waiting for a response to the pending SR transmission (i.e., while monitoring the uplink grant transmitted from the base station device 20) and an available PUCCH resource is in the Cell DRX active period, the terminal device 10 performs SR transmission using the PUCCH resource at the next SR transmission opportunity. The terminal device 10 may determine that the PUCCH resource is available when any PUCCH resource is configured, or may determine that the PUCCH resource is available when there are one or more PUCCH resources corresponding to a high-priority LCH.

[0144] In the case of SR transmission via PUCCH, if at least Cell DRX is deactivated while waiting for a response to the pending SR transmission (i.e., while monitoring the uplink grant transmitted from the base station device 20) and there are no valid PUCCH resources in the Cell DRX active period, the terminal device 10 performs SR transmission using random access at the next SR transmission opportunity.

[0145] As described above, according to the second embodiment, the terminal device 10 and the base station device 20 can appropriately transmit high-priority scheduling requests in consideration of the dynamically changing active / inactive periods of Cell DRX, even in a cell to which Cell DTX / DRX is applied for power saving. This makes it possible to efficiently transmit and receive data while suppressing an increase in power consumption of the base station device 20.

[0146] The base station device 20 may notify the terminal device 10 of the activation or deactivation of Cell DRX using an individual RRC message.

[0147] Furthermore, according to the first and second embodiments, in a cell to which Cell DTX / DRX is applied as a network power reduction technique, the terminal device 10 and the base station device 20 can efficiently transmit and receive data while suppressing an increase in power consumption of the base station device 20. That is, the terminal device 10 and the base station device 20 can improve the efficiency of power saving related to wireless communication between the terminal device 10 and the base station device 20 without affecting high-priority services.

[0148] The above-described embodiments are intended to facilitate understanding of the present invention and are not to be construed as limiting the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention also includes equivalents thereof.

[0149] <Hardware Configuration of Each Device in Each Embodiment> The hardware configuration of each device in the wireless communication system of each embodiment will be described with reference to FIGS. 10 and 11. FIG.

[0150] 10 is a diagram illustrating an example of the hardware configuration of the terminal device 10. As illustrated in FIG. 10, the terminal device 10 includes, as hardware components, a radio frequency (RF) circuit 32 including an antenna 31, a central processing unit (CPU) 33, and a memory 34. The terminal device 10 may further include a display device such as a liquid crystal display (LCD) connected to the CPU 33. The memory 34 includes at least one of a random access memory (RAM) such as a synchronous dynamic random access memory (SDRAM), a read only memory (ROM), and a flash memory, and stores programs, control information, and data signals.

[0151] The correspondence between the functional configuration of the terminal device 10 shown in Fig. 2 and the hardware configuration of the terminal device 10 shown in Fig. 10 will be described. The transmitting / receiving antenna unit 19, the transmitter unit 17, and the receiver unit 15 are realized by, for example, an RF circuit 32, or an antenna 31 and an RF circuit 32. The control unit 13 and the processing unit 11 are realized by, for example, a CPU 33, a memory 34, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and a large scale integration (LSI).

[0152] Fig. 11 is a diagram illustrating an example of the hardware configuration of the base station device 20. As shown in Fig. 11, the base station device 20 includes, as hardware components, an RF circuit 42 equipped with an antenna 41, a CPU 43, a DSP 44, a memory 45, and a network IF (Interface) 46. The CPU 43 is connected via a bus to enable input and output of various signals and data signals. The memory 45 includes at least one of a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data signals.

[0153] The correspondence between the functional configuration of the base station device 20 shown in Fig. 3 and the hardware configuration of the base station device 20 shown in Fig. 11 will be described. The transmitting / receiving antenna unit 29, the transmitter 27, and the receiver 25 are realized by, for example, an RF circuit 42, or an antenna 41 and an RF circuit 42. The control unit 23 and the processing unit 21 are realized by, for example, a CPU 43, a DSP 44, a memory 45, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an ASIC, an FPGA, and an LSI.

[0154] REFERENCE SIGNS LIST 1 wireless communication system 10 terminal device 20 base station device 30 core network 11, 21 processing unit 13, 23 control unit 15, 25 receiving unit 17, 27 transmitting unit 19, 29 transmitting / receiving antenna unit 31, 41 antenna 32, 42 RF circuit 33, 43 CPU 34, 45 memory 44 DSP 46 network IF 111, 211 radio resource processing unit 113, 213 discontinuous transmission / reception processing unit

Claims

1. A terminal device that communicates with a base station device, comprising: a receiving unit that receives from the base station device setting information of a first active period indicating a transmission and reception period on a cell-by-cell basis and a second active period indicating a transmission and reception period for each terminal device; a processing unit that, when transmitting a scheduling request requesting uplink resources, determines a method of controlling the scheduling request based on the priority of the service that triggers the scheduling request, the timing at which the scheduling request was triggered, information on the first active period, information indicating a predetermined period measured from the triggering timing, and a setting state of resources of a physical uplink control channel for transmitting the scheduling request; and a transmitting unit that transmits the scheduling request based on the determination.

2. The terminal device according to claim 1, wherein, when the triggered timing is within the first active period and resources of the physical uplink control channel are unavailable, if a next first active period has not started when a predetermined period has elapsed from the triggered timing, the terminal device starts a random access procedure for transmitting the scheduling request.

3. The terminal device of claim 2, which starts the random access procedure for transmitting the scheduling request when the remainder obtained by dividing the value obtained by converting the triggered timing into subframes by the first active period is smaller than the value of an offset time in subframe units from the beginning of a frame indicating the start time of the first active period.

4. A terminal device as described in claim 2, wherein, when the random access procedure is initiated, the period after the uplink resource received from the base station device is transmitted including an identifier of the terminal device in the cell is regarded as the second active period.

5. A terminal device as described in claim 4, wherein when the random access procedure is started, an identifier of the terminal device in the cell is included in the uplink resource received from the base station device and transmitted, and monitoring of an identifier indicating activation or deactivation of the first active period is started during the second active period.

6. The terminal device according to claim 1, wherein the determination of the control method for the scheduling request is performed respectively at the timing when the scheduling request is triggered and at the timing when an identifier indicating activation or deactivation of the first active period is received.

7. A base station device that communicates with a terminal device, comprising: a transmitting unit that transmits to the terminal device setting information of a first active period indicating a transmission and reception period on a cell-by-cell basis and a second active period indicating a transmission and reception period for each of the terminal devices; a processing unit that sets information on the first active period, information indicating a predetermined period measured from the trigger timing, and physical uplink control channel resources for transmitting the scheduling request, in order to allow the terminal device to determine a control method for a scheduling request requesting uplink resources corresponding to a high priority service; and a receiving unit that receives the scheduling request transmitted based on the determination of the terminal device.

8. A base station device as described in claim 7, which instructs the terminal device to permit the initiation of a random access procedure for transmitting the scheduling request during the first active period by setting a predetermined period measured from the triggered timing.

9. A base station device as described in claim 7, which sets the priority of a logical channel used to determine the selection of the physical uplink control channel when the terminal device transmits a scheduling request requesting uplink resources corresponding to the high priority service.

10. A base station device as described in claim 8, wherein when the terminal device initiates the random access procedure and receives an identifier of the terminal device in a cell from an uplink resource included in a random access response, the base station device transmits an identifier indicating activation or deactivation of the first active period during the second active period.

11. A control method for a terminal device, comprising: a step of receiving, from a base station device, setting information of a first active period indicating a transmission and reception period on a cell-by-cell basis and a second active period indicating a transmission and reception period for each of the terminal devices; when transmitting a scheduling request requesting uplink resources, a step of determining a control method for the scheduling request based on the priority of the service that triggers the scheduling request, the timing at which the scheduling request was triggered, information on the first active period, information indicating a predetermined period measured from the triggering timing, and a setting state of resources of a physical uplink control channel for transmitting the scheduling request; and a step of transmitting the scheduling request based on the determination.

12. A control method for a base station device, comprising: a step of transmitting, to a terminal device, setting information on a first active period indicating a transmission and reception period on a cell-by-cell basis and a second active period indicating a transmission and reception period for each terminal device; a step of setting information on the first active period, information indicating a predetermined period measured from the trigger timing, and physical uplink control channel resources for transmitting the scheduling request, in order to have the terminal device determine a control method for a scheduling request requesting uplink resources corresponding to a high priority service; and a step of receiving the scheduling request transmitted based on the determination of the terminal device.

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