WO2024071076A1 - Communication device and communication method - Google Patents

Abstract

A communication device (100) that performs a discontinuous reception (DRX) operation is provided with: a control unit (120) that controls the DRX operation on the basis of each of a plurality of DRX configurations that are applied to a single cell group configured in the communication device; and a reception unit (112) that receives control information for controlling the DRX operation from a network. The reception unit receives from the network (10) a predetermined parameter that differs for each of the DRX configurations configured in the communication device. The control unit identifies, on the basis of the predetermined parameter, a DRX configuration to be controlled on the basis of the control information, from among the plurality of DRX configurations.

Description

Communication device and communication method CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority to patent application serial number 2022-155585, filed September 28, 2022, the entire contents of which are incorporated herein by reference.

This disclosure relates to a communication device and a communication method for use in a mobile communication system.

3GPP (registered trademark; the same applies below) (3rd Generation Partnership Project), a standardization project for mobile communications systems, has launched a work item to consider power saving technologies suited to the characteristics of XR (Extended Reality) services.

In the XR service, it is assumed that multiple traffic flows with different traffic characteristics (e.g., traffic cycles) are provided to a communication device. Because the reception timing of each of the multiple traffic flows differs due to differences in the traffic cycles, the communication device may need to extend the time it is in an awake state when performing DRX operation based on a single discontinuous reception (DRX) setting.

Therefore, it is assumed that the communication device will perform DRX operation based on one DRX setting for one traffic flow. This will shorten the time that the communication device is in the active state, and it has been reported that this will result in power saving effects (see Non-Patent Document 1).

The communication device according to the first aspect is a communication device that performs discontinuous reception (DRX) operation. The communication device includes a control unit that controls the DRX operation based on each of a plurality of DRX settings applied to one cell group set in the communication device, and a receiving unit that receives control information for controlling the DRX operation from a network. The receiving unit receives from the network a predetermined parameter that differs for each DRX setting set in the communication device. The control unit identifies a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.

The communication method according to the second aspect is a communication method executed by a communication device that performs discontinuous reception (DRX) operation. The communication method includes the steps of controlling the DRX operation based on each of a plurality of DRX settings applied to one cell group set in the communication device, receiving control information for controlling the DRX operation from a network, receiving from the network a predetermined parameter that differs for each DRX setting set in the communication device, and identifying a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.

The objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.
FIG. 1 is a diagram showing a configuration of a mobile communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a protocol stack according to the embodiment. FIG. 3 is a diagram for explaining a timer related to DRX. FIG. 4 is a diagram showing a configuration of a UE according to the embodiment. FIG. 5 is a diagram showing a configuration of a base station according to the embodiment. FIG. 6 is a sequence diagram for explaining a first operation example and a second operation example according to the embodiment. FIG. 7 is a flowchart for explaining an example of the operation of UE 100 in a first operation example according to the embodiment.

The mobile communication system according to the embodiment will be described with reference to the drawings. In the drawings, the same or similar parts are denoted by the same or similar reference numerals.

Consider a case in which multiple DRX settings are applied to one cell group configured in a communications device in order for the communications device to receive multiple traffic flows. In this case, it is possible that the time during which an active state based on one DRX setting is active may overlap with the time during which an active state based on another DRX setting is active. If the communications device receives control information for controlling DRX operation based on a DRX setting during this overlapping time, there is a concern that it will not be possible to appropriately control DRX operation because it will not know which DRX setting is the target of control based on the control information.

Therefore, one of the objectives of this disclosure is to provide a communication device and a communication method that enable appropriate control of DRX operation.

(System configuration)
First, the configuration of a mobile communication system 1 according to the present embodiment will be described with reference to Fig. 1. The mobile communication system 1 is, for example, a system conforming to the 3GPP Technical Specification (TS). In the following, the mobile communication system 1 will be described using a 3GPP standard 5th Generation System (5G system), i.e., a mobile communication system based on NR (New Radio) as an example.

The mobile communication system 1 has a network 10 and a user equipment (UE) 100 that communicates with the network 10. The network 10 includes a 5G radio access network, NG-RAN (Next Generation Radio Access Network) 20, and a 5G core network, 5GC (5G Core Network) 30.

UE100 is a communication device that communicates via base station 200. UE100 may be a device used by a user. UE100 may be a user device defined in the technical specifications of 3GPP. UE100 is a mobile device such as a mobile phone terminal such as a smartphone, a tablet terminal, a notebook PC, a communication module, or a communication card. UE100 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. UE100 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. UE100 may be a sensor or a device provided therein. Note that UE100 may be called by other names such as a terminal, a terminal device, 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. Additionally, UE 100 is an example of a terminal, and terminals may include factory equipment, etc.

NG-RAN20 includes multiple base stations 200. Each base station 200 manages at least one cell. A cell constitutes the smallest unit of a communication area. One cell belongs to one frequency (carrier frequency). The term "cell" may refer to a wireless communication resource, and may also refer to a communication target of UE100. Each base station 200 can perform wireless communication with UE100 located in its own cell. The base station 200 communicates with UE100 using a protocol stack of the RAN. Details of the protocol stack will be described later. In addition, the base station 200 is connected to other base stations 200 (which may be referred to as adjacent base stations) via an Xn interface. The base station 200 communicates with adjacent base stations via an Xn interface. In addition, the base station 200 provides NR user plane and control plane protocol terminations toward the UE100, and is connected to the 5GC30 via an NG interface. Such an NR base station 200 may be referred to as a gNodeB (gNB).

5GC30 includes a core network device 300. The core network device 300 includes, for example, an AMF (Access and Mobility Management Function) and/or a UPF (User Plane Function). The AMF manages the mobility of the UE 100. The UPF provides functions specialized for U-plane processing. The AMF and the UPF are connected to the base station 200 via an NG interface.

(Example of protocol stack configuration)
Next, an example of the configuration of a protocol stack according to this embodiment will be described with reference to FIG.

The protocol for the wireless section between UE100 and base station 200 includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and an RRC layer.

The PHY layer performs encoding/decoding, modulation/demodulation, antenna mapping/demapping, and resource mapping/demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via a physical channel.

The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resources to be allocated to UE100.

The RLC layer uses the functions of the MAC layer and PHY layer to transmit data to the RLC layer on the receiving side. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via logical channels.

The PDCP layer performs header compression/decompression, and encryption/decryption.

The SDAP (Service Data Adaptation Protocol) layer may be provided as a layer above the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer maps IP flows, which are the units by which the core network performs QoS (Quality of Service) control, to radio bearers, which are the units by which the AS (Access Stratum) performs QoS control.

The RRC layer controls logical channels, transport channels, and physical channels in response to the establishment, re-establishment, and release of radio bearers. RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of base station 200. When there is an RRC connection between the RRC of UE100 and the RRC of base station 200, UE100 is in an RRC connected state. When there is no RRC connection between the RRC of UE100 and the RRC of base station 200, UE100 is in an RRC idle state. When the RRC connection between the RRC of UE100 and the RRC of base station 200 is suspended, UE100 is in an RRC inactive state.

The NAS layer, which is located above the RRC layer in UE100, performs session management and mobility management for UE100. NAS signaling is transmitted between the NAS layer of UE100 and the NAS layer of the core network device 300.

In addition, UE100 has an application layer, etc. in addition to the radio interface protocol.

(Radio Frame Structure)
In the 5G system, downlink transmission and uplink transmission are configured within a radio frame of 10 ms duration. For example, a radio frame is configured with 10 subframes. For example, one subframe may be 1 ms. Also, one subframe may be configured with one or more slots. For example, the number of symbols constituting one slot is 14 in a normal CP (Cyclic Prefix) and 12 in an extended CP. Also, the number of slots constituting one subframe changes according to the set subcarrier interval. For example, for a normal CP, when the subcarrier interval is set to 15 kHz, the number of slots per subframe is 1 (i.e., 14 symbols), when the subcarrier interval is set to 30 kHz, the number of slots per subframe is 2 (i.e., 28 symbols), when the subcarrier interval is set to 60 kHz, the number of slots per subframe is 4 (i.e., 56 symbols), and when the subcarrier interval is set to 120 kHz, the number of slots per subframe is 8 (i.e., 112 symbols). Furthermore, when the subcarrier interval is set to 60 kHz for the extended CP, the number of slots per subframe is 4 (i.e., 48 symbols). That is, the number of slots constituting one subframe is determined based on the subcarrier interval set by the base station 200. Also, the number of symbols constituting one subframe is determined based on the subcarrier interval set by the base station 200. That is, the number of symbols constituting a 1 ms subframe is determined based on the subcarrier interval set by the base station 200, and the length of each symbol (length in the time direction) changes.

(DRX)
With reference to Fig. 3, discontinuous reception (DRX) in the mobile communication system 1 according to the embodiment will be described. Fig. 3A is a diagram for explaining a timer related to DRX in uplink transmission. Fig. 3B is a diagram for explaining a timer related to DRX in downlink transmission.

In order to reduce the power consumption of UE100, UE100 does not constantly monitor the physical downlink control channel (PDCCH) of UE100 as an operation during DRX (hereinafter referred to as DRX operation), but monitors the PDCCH only at regular cycles (i.e., DRX cycles). In particular, DRX performed by UE100 in an RRC connected state is sometimes called C-DRX.

The UE 100 is set with a DRX cycle consisting of an on period and an off period. During the on period, the state of the UE 100 is an awake state in which the UE 100 monitors the PDCCH. The UE 100 in the awake state is active to monitor the PDCCH. The awake state may be referred to as, for example, an active state or a DRX activated state. The on period may also be referred to as, for example, a DRX on period, on time, or active time as a period in which the PDCCH is monitored. During the off period, the state of the UE 100 is a sleep state in which the UE 100 does not need to monitor the PDCCH. The UE 100 in the sleep state is inactive. The sleep state may be referred to as, for example, a DRX sleep state, a sleep mode, a DRX mode, or a power saving mode. The off period may also be referred to as, for example, a DRX off period, off time, or inactive time as a period in which the PDCCH is not monitored.

As DRX cycles, a long DRX cycle and a short DRX cycle are specified. The long DRX cycle consists of an on period and an off period. The short DRX cycle is an additional DRX cycle that is set together with the long DRX cycle. The short DRX cycle is a DRX cycle that is shorter than the long DRX cycle.

DRX setting parameters, such as drx-onDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, drx-LongCycleStartOffset, and drx-SlotOffset, are set individually for each cell group set in UE 100.

Hereinafter, in this embodiment, for ease of explanation, it will be described that DRX (DRX operation) is set for one cell group. That is, the operation in this embodiment may be an operation when DRX (DRX operation) is set for one cell group. That is, the operation in this embodiment may be an operation when DRX (DRX operation) is set for one serving cell (for example, a downlink serving cell, also referred to as a downlink component carrier). Also, the operation in this embodiment may be an operation when DRX (DRX operation) is set for each DL BWP (Downlink Bandwidth Part) set in each of one or more serving cells. That is, the operation in this embodiment may be an operation when DRX (DRX operation) is set for each DL BWP in each of one or more serving cells. That is, in this embodiment, the parameters for DRX setting (i.e., DRX (DRX operation)) may be set for each of one or more cell groups. Also, in this embodiment, the parameters for DRX setting (i.e., DRX (DRX operation)) may be set for each of one or more serving cells. Also, in this embodiment, the parameters for DRX setting (i.e., DRX (DRX operation)) may be set for each of one or more DL BWPs.

drx-onDurationTimer may indicate the duration at the beginning of a DRX cycle. For example, drx-onDurationTimer is a parameter that specifies the amount of time of the DRX on period of each DRX cycle. Thus, drx-onDurationTimer is set to the timer value of the DRX on duration timer (drx-onDurationTimer) used to time the DRX on period. As shown in FIG. 3, UE 100 is in an active state (e.g., considered to be in an active time) while the DRX on duration timer (hereinafter sometimes referred to as ODT) is running (operating). If UE 100 does not receive a PDCCH by the expiration of ODT, it transitions to a sleep state until the start of the next on period.

The drx-InactivityTimer may indicate the duration after the PDCCH occasion in which a PDCCH indicates a new UL or DL transmission. Here, the PDCCH indicating the uplink transmission may include a DCI format used for uplink scheduling (e.g., PUSCH scheduling). Also, the PDCCH indicating the downlink transmission may include a DCI format used for downlink scheduling (e.g., PDSCH scheduling). For example, the drx-InactivityTimer is a parameter that specifies the period during which the UE 100 should be active after successfully decoding a PDCCH indicating a new transmission. Therefore, the drx-InactivityTimer is set to the timer value of the DRX inactivity timer (drx-InactivityTimer) used to time the active time, for example. As shown in FIG. 3, the DRX inactivity timer (hereinafter sometimes referred to as IAT) is started or restarted when the UE 100 receives a PDCCH for a new transmission (e.g., UL, DL, or SL (sidelink)) during the on period. Therefore, the UE 100 remains in an awake state while the IAT is running. The IAT may be a timer indicating the period during which the UE 100 should be in an awake state after successfully decoding a PDCCH indicating a new transmission. The UE 100 monitors the PDCCH until the IAT expires. When the IAT expires, the UE 100 transitions to a sleep state (DRX mode).

The drx-HARQ-RTT-TimerUL may indicate the minimum duration before a UL HARQ retransmission grant is expected. Here, the grant may include a PDCCH indicating an uplink transmission. For example, the drx-HARQ-RTT-TimerUL is a parameter used in the retransmission process of uplink data. The drx-HARQ-RTT-TimerUL is a parameter that specifies the period during which the UE 100 can expect an uplink retransmission. The drx-HARQ-RTT-TimerUL is set to the timer value of a timer (drx-HARQ-RTT-TimerUL (timer)) used to time the period. The UE 100 maintains a sleep state while the timer is running. The timer may be hereinafter referred to as a HARQ RTT timer or a HARQ RTT UL timer. As shown in FIG. 3A, the UE 100 starts the HARQ RTT timer (specifically, the drx-HARQ-RTT-TimerUL timer) with the first symbol immediately after transmitting the PUSCH. The UE 100 transitions to an active state in response to expiration of the timer. In addition, drx-HARQ-RTT-TimerUL may be specified (set, controlled) for each uplink HARQ process (per UL HARQ process).

The drx-HARQ-RTT-TimerDL may indicate the minimum duration before a DL assignment for HARQ retransmission. Here, the downlink assignment may include a PDCCH indicating downlink transmission. For example, the drx-HARQ-RTT-TimerDL is a parameter used in the retransmission process of downlink data. The drx-HARQ-RTT-TimerDL is a parameter that specifies the period during which the UE 100 can expect a retransmission. The drx-HARQ-RTT-TimerDL is set to the timer value of a timer (drx-HARQ-RTT-TimerDL (timer)) used to time the period. The UE 100 maintains a sleep state while the timer is running. The timer may be hereinafter referred to as a HARQ RTT timer or a HARQ RTT DL timer. As shown in FIG. 3B, when the UE 100 receives a new downlink transmission, the UE 100 starts the HARQ RTT timer (specifically, the drx-HARQ-RTT-TimerDL timer) with the first symbol after transmitting a negative acknowledgement (NACK) in the uplink. The UE 100 transitions to an active state in response to expiration of the timer. In addition, drx-HARQ-RTT-TimerDL may be specified (set, controlled) for each downlink HARQ process (per UL HARQ process).

drx-RetransmissionTimerUL may indicate the maximum duration until a grant for UL retransmission is received. Here, the grant for uplink retransmission may include a PDCCH indicating uplink retransmission. For example, drx-RetransmissionTimerUL is a parameter used in the retransmission process of uplink data. drx-RetransmissionTimerUL is set to the maximum number of slots that the UE should monitor the PDCCH when the UE can expect a grant for uplink retransmission. The drx-RetransmissionTimerUL is set to the timer value of a timer (drx-RetransmissionTimerUL timer) used to time the duration of a specified slot. This timer may be referred to as a DRX retransmission timer or a DRX retransmission UL timer. This timer may be associated with each HARQ process. As shown in FIG. 3A, the UE 100 starts the DRX retransmission UL timer at the next symbol when the drx-HARQ-RTT-TimerUL timer expires. The UE 100 is in an awake state while this timer is running. The UE 100 stops the DRX retransmission UL timer as soon as it detects an uplink transmission for the corresponding HARQ process. In addition, drx-RetransmissionTimerUL may be specified (set, controlled) for each uplink HARQ process (per UL HARQ process).

drx-RetransmissionTimerDL may indicate the maximum duration until a DL retransmission is received. Here, downlink retransmission may include retransmission of downlink data (i.e., retransmission in PDSCH). Downlink data is also referred to as DL-SCH data. For example, drx-RetransmissionTimerDL is a parameter used in the retransmission process of downlink data. drx-RetransmissionTimerDL is set to the maximum number of slots that the UE should monitor the PDCCH when the UE can expect a retransmission from base station 200. The drx-RetransmissionTimerDL is set to the timer value of a timer (drx-RetransmissionTimerDL timer) used to time the duration of a specified slot. This timer may be referred to as a DRX retransmission timer or a DRX retransmission DL timer. This timer may be associated with each HARQ process. As shown in FIG. 3B, when the drx-HARQ-RTT-TimerDL timer expires, the UE 100 starts the DRX retransmission DL timer at the next symbol. The UE 100 is in an awake state while this timer is running. The UE 100 stops the DRX retransmission DL timer as soon as it detects a downlink transmission for the corresponding HARQ process. In addition, drx-RetransmissionTimerDL may be specified (set, controlled) for each downlink HARQ process (per UL HARQ process).

For example, UE100 may consider the time when drx-onDurationTimer or drx-InactivityTimer set for one cell group is operating to be the active time for the serving cell in that one cell group. Also, UE100 may consider the time when drx-RetransmissionTimerUL or drx-RetransmissionTimerDL is operating in any of the serving cells in the one cell group to be the active time for the serving cell in that one cell group. For example, UE100 may monitor the PDCCH when the one cell group is in the active time. That is, UE100 may monitor the PDCCH in the serving cell in the one cell group when the one cell group is in the active time. Here, the cell group in which the parameters for DRX setting (i.e., DRX (DRX operation)) are set is also referred to as the DRX group. For example, the base station 200 may transmit an RRC message including information indicating a DRX group including one or more serving cells. The UE 100 may identify the DRX group based on the information indicating the DRX group. For example, the DRX group may be a group of one or more serving cells having (set) the same active time. When DRX (DRX operation) is set, the active time for the serving cells in one DRX group may include the time during which any of the drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerUL, and drx-RetransmissionTimerDL set for the one DRX group is operating. The drx-LongCycleStartOffset is a parameter for controlling the start position of the long DRX cycle. drx-LongCycleStartOffset is used to determine the length of the long DRX cycle and the starting subframe number within the long DRX cycle. drx-SlotOffset is a parameter that specifies the start of the on-period with respect to the start of the subframe.

Also, when UE100 receives a DRX command MAC CE or a long DRX command MAC CE from the network (base station 200), it ends the current on-period (active time). Specifically, UE100 stops ODT and IAT.

When UE100 receives the DRX command MAC CE, it transitions to a normal DRX cycle. Specifically, when a short DRX cycle is set in UE100, it transitions to a short DRX cycle mode. When a short DRX cycle is not set in UE100, it transitions to a long DRX cycle mode. On the other hand, when UE100 receives a long DRX command MAC CE, it transitions to a long DRX cycle.

(Assumed scenario)
An assumed scenario in the mobile communication system 1 according to the embodiment will be described. In the 3GPP, which is a standardization project for mobile communication systems, a work item has been launched to study power saving technology suited to the characteristics of XR services. The characteristics of XR traffic (XR service) include, for example, a non-integer period such as 60, 120 fps (16.67, 8.33 ms), jitter (variation in the arrival timing of traffic due to encoding and NW transmission delay), and multiple data streams (multiple flows, for example, I frames and P frames, video and voice/data, etc.) with different traffic characteristics and QoS requirements.

In an XR service, it is assumed that multiple traffic flows with different traffic characteristics (e.g., traffic cycles) will be provided to a communication device. Because the reception timing of each of the multiple traffic flows differs depending on the traffic cycle, the communication device may need to extend the time it is in an awake state when performing a discontinuous reception (DRX) operation based on a single DRX setting. Therefore, it is assumed that the communication device will perform a DRX operation based on one DRX setting for one traffic flow. This has been reported to shorten the awake state of the communication device and provide a power saving effect.

Consider a case in which multiple DRX settings are applied to one cell group configured in a communication device in order for the communication device to receive multiple traffic flows. In this case, it is possible that the time of an activated state based on one DRX setting overlaps with the time of an activated state based on another DRX setting. If the communication device receives control information for controlling DRX operation based on a DRX setting during this overlapping time, there is a concern that it will not be possible to appropriately control the DRX operation because it will not know which DRX setting is the target of control based on the control information. Therefore, this disclosure describes an example of an operation for enabling appropriate control of DRX operation.

(UE Configuration)
A configuration of the UE 100 according to the embodiment will be described with reference to Fig. 4. The UE 100 includes a communication unit 110 and a control unit 120.

The communication unit 110 performs wireless communication with the base station 200 by transmitting and receiving radio signals to and from the base station 200. The communication unit 110 has at least one transmission unit 111 and at least one reception unit 112. The transmission unit 111 and the reception unit 112 may be configured to include multiple antennas and RF circuits. The antenna converts a signal into radio waves and radiates the radio waves into space. The antenna also receives radio waves in space and converts the radio waves into a signal. The RF circuit performs analog processing of the signal transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

The control unit 120 performs various controls in the UE 100. The control unit 120 controls communication with the base station 200 via the communication unit 110. The operations of the UE 100 described above and below may be operations under the control of the control unit 120. The control unit 120 may include at least one processor capable of executing programs and a memory for storing the programs. The processor may execute the programs to perform the operations of the control unit 120. The control unit 120 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of the RAN protocol stack. The memory stores the programs executed by the processor, parameters related to the programs, and data related to the programs. The memory may include at least one of ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access Memory), and flash memory. All or a portion of the memory may be contained within the processor.

In the UE 100 configured in this manner, the control unit 120 controls the DRX operation based on each of the multiple DRX settings. The receiving unit 112 receives control information from the network 10. The receiving unit 112 receives a predetermined parameter from the network 10. The control unit 120 identifies a target DRX setting from among the multiple DRX settings to be controlled based on the control information, based on the predetermined parameter. This allows the UE 100 to identify the target DRX setting based on the predetermined parameter, even if the UE 100 receives control information during overlapping periods of time in the activated state based on the multiple DRX settings. This allows the UE 100 to grasp the target of the control information and appropriately control the DRX operation.

(Base station configuration)
The configuration of the base station 200 according to the embodiment will be described with reference to Fig. 5. The base station 200 includes a communication unit 210, a network communication unit 220, and a control unit 230.

The communication unit 210, for example, receives a radio signal from the UE 100 and transmits a radio signal to the UE 100. The communication unit 210 has at least one transmission unit 211 and at least one reception unit 212. The transmission unit 211 and the reception unit 212 may be configured to include an RF circuit. The RF circuit performs analog processing of the signal transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

The network communication unit 220 transmits and receives signals to the network. For example, the network communication unit 220 receives signals from adjacent base stations connected via an Xn interface, which is an interface between base stations, and transmits signals to the adjacent base stations. The network communication unit 220 also receives signals from a core network device 300 connected via an NG interface, and transmits signals to the core network device 300.

The control unit 230 performs various controls in the base station 200. The control unit 230 controls, for example, communication with the UE 100 via the communication unit 210. The control unit 230 also controls, for example, communication with a node (e.g., an adjacent base station, a core network device 300) via the network communication unit 220. The operations of the base station 200 described above and below may be operations under the control of the control unit 230. The control unit 230 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute a program to perform the operations of the control unit 230. The control unit 230 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of the RAN protocol stack. The memory stores the program executed by the processor, parameters related to the program, and data related to the program. All or a part of the memory may be included in the processor.

(First operation example)
6 and 7, a first operation example of the mobile communication system 1 will be described. In the following, as an example of communication (transmission and/or reception) between the UE 100 and the network 10, communication between the UE 100 and the base station 200 will be described as an example.

The transmitting unit 211 of the base station 200 may transmit to the UE 100 a radio resource control (RRC) message including multiple DRX settings to be applied to one cell group. The receiving unit 112 of the UE 100 may receive from the base station 200 a radio resource control (RRC) message including multiple DRX settings. The transmitting unit 211 of the base station 200 may transmit multiple DRX settings in step S101 described below.

UE100 may have multiple DRX settings for one cell group. Therefore, UE100 may apply multiple DRX settings to one cell group. UE100 performs DRX operation based on each of the multiple DRX settings applied to one cell group. Control unit 120 of UE100 applies the multiple DRX settings and controls DRX operation based on each of the multiple DRX settings.

Step S101:
6, the transmitting unit 211 of the base station 200 may transmit the predetermined parameter to the UE 100. The receiving unit 112 of the UE 100 may receive the predetermined parameter from the base station 200. The predetermined parameter may be included in, for example, a radio resource control (RRC) message.

The specified parameters are parameters that differ for each DRX setting set in UE100. The specified parameters may be, for example, parameters that are individually assigned to UE100. The specified parameters may be UE-specific parameters. Therefore, the specified parameters are not cell-specific parameters that are commonly assigned to UE100 in a cell. The specified parameters may be, for example, the following:

First, the predetermined parameter may be a predetermined radio network temporary identifier (RNTI) that is different for each DRX setting. Therefore, the predetermined RNTI may be set individually for each DRX setting. That is, a predetermined RNTI may be set for each of one or more DRX settings. For example, each of one or more DRX settings may correspond to each of one or more predetermined RNTIs. The predetermined RNTI may be, for example, a cell-radio network temporary identifier (C-RNTI). The C-RNTI is an identifier used for RRC connection and/or scheduling. For example, the C-RNTI may be used for dynamically scheduled unicast transmission. That is, the C-RNTI may be used (applied) for scheduling the physical downlink shared channel (PDSCH) and/or the physical uplink shared channel (PUSCH). In addition, when the predetermined RNTI is a C-RNTI, the UE 100 may have previously acquired a C-RNTI (suitably referred to as a first C-RNTI) acquired in a random access procedure. In step S101, the UE 100 may acquire a C-RNTI (suitably referred to as a second C-RNTI) different from the first C-RNTI. Thus, a plurality of C-RNTIs may be assigned to the UE 100. For example, a first value C-RNTI and a second value C-RNTI may be configured for the UE 100 as a plurality of C-RNTIs. The predetermined RNTI may be a configured scheduling-radio network temporary identifier (CS-RNTI). For example, the CS-RNTI may be used for a scheduled unicast transmission to be configured. The CS-RNTI is an identifier used for downlink semi-persistent scheduling (SPS) and uplink configured grants. A plurality of CS-RNTIs may be assigned to the UE 100. For example, a first value of the CS-RNTI and a second value of the CS-RNTI may be configured for the UE 100 as a plurality of CS-RNTIs.

Secondly, the specified parameter may be a search space set and/or a search space set group that differs for each DRX setting. Therefore, the specified parameter may be a search space set identifier (searchSpaceId), which is an identifier of a search space set. Also, the specified parameter may be a search space set group identifier (searchSpaceGroupId), which is an identifier of a search space set group. That is, a search space set identifier and/or a search space set group identifier may be set for each of one or more DRX settings. For example, each of one or more DRX settings may correspond to each of one or more search space set identifiers. Also, each of one or more DRX settings may correspond to each of one or more search space set group identifiers.

For example, base station 200 may transmit an RRC message including information regarding the search space set and/or the search space set group. UE 100 may determine the search space set and/or the search space set group based on the information regarding the search space set and/or the search space set group. For example, the information regarding the search space set and/or the search space set group may include one or more search space set identifiers and/or one or more search space set group identifiers. Furthermore, the information regarding the search space set and/or the search space set group may include information indicating a periodicity and/or an offset value of the search space set and/or the search space set group. Furthermore, the information regarding the search space set and/or the search space set group may include information indicating a type of search space set. Here, the type of search space set may include a common search space set (CSS) and/or a UE-specific search space set (USS). Furthermore, the information on the search space set and/or the search space set group may include information indicating one or more DCI formats. That is, the information on the search space set and/or the search space set group may include information indicating one or more DCI formats monitored in the search space set and/or the search space set group.

Thirdly, the predetermined parameter may be a radio bearer identifier for identifying a radio bearer. The radio bearer identifier may be, for example, an identifier (DRB Identity) for identifying a data radio bearer. That is, a radio bearer identifier may be set for each of one or more DRX settings. Also, each of one or more DRX settings may correspond to each of one or more radio bearer identifiers. Fourthly, the predetermined parameter may be a logical channel identifier (LogicalChannelID: LCID) for identifying a logical channel. That is, a logical channel identifier may be set for each of one or more DRX settings. Also, each of one or more DRX settings may correspond to each of one or more logical channel identifiers. Fifthly, the predetermined parameter may be a DRX identifier, which will be described later. That is, a DRX identifier may be set for each of one or more DRX settings. Also, one or more DRX settings may correspond to one or more DRX identifiers. Sixth, the predetermined parameter may be a DCI format indicating a type of DCI. That is, a DCI format (e.g., a monitored DCI format) may be set for each of one or more DRX settings. Also, one or more DRX settings may correspond to one or more DCI formats. For example, one or more DCI formats may include a DCI format used for scheduling the PDSCH and/or a DCI format used for scheduling the PUSCH. Also, the DCI format used for scheduling the PDSCH may include multiple DCI formats (e.g., DCI format 1_0, DCI format 1_1, and/or DCI format 1_2). Also, the DCI format used for scheduling the PUSCH may include multiple DCI formats (e.g., DCI format 0_0, DCI format 0_1, and/or DCI format 0_2). Seventh, the predetermined parameters may include at least one of the parameters described above.

The transmitter 211 of the base station 200 may also transmit information indicating (multiple) DRX settings (e.g., DRX-config) used to set parameters related to DRX to the UE 100. The receiver 112 of the UE 100 may receive information indicating (multiple) DRX settings from the base station 200.

As described above, the DRX setting may be associated with a specific parameter. That is, a specific parameter may be set for each DRX setting. The DRX setting may include a specific parameter associated with the DRX setting. In addition, an identifier for identifying the DRX setting (hereinafter, a DRX identifier) may be associated with the specific parameter.

Furthermore, the transmitting unit 211 of the base station 200 may transmit correspondence information for identifying the correspondence between the specified parameters and the DRX settings to the UE 100. The receiving unit 112 of the UE 100 may receive the correspondence information from the base station 200. The correspondence information may be, for example, a list of the DRX settings and the specified parameters.

Step S102:
The transmitter 211 of the base station 200 transmits control information for controlling the DRX operation to the UE 100. The receiver 112 of the UE 100 receives the control information from the base station 200. The controller 120 of the UE 100 may execute the process of step S103 below based on the control information. The control information may be, for example, the following information.

First, the control information may be downlink control information (DCI) transmitted on a physical downlink control channel (PDCCH). The receiver 112 may receive, as the control information, the DCI transmitted in step S102, for example, by applying a predetermined parameter.

Secondly, the control information may be a predetermined medium access control (MAC) control element (CE) transmitted on a physical downlink shared channel (PDSCH). The predetermined MAC CE may be, for example, a DRX command MAC CE or a long DRX command MAC CE. The predetermined MAC CE may also be another MAC CE for controlling DRX operation. Here, when the following operation is applied to a predetermined MAC CE, the DCI format (PDCCH) may be a DCI format (PDCCH) used for scheduling the PDSCH used to transmit the predetermined MAC CE. For example, the control unit 120 of the UE 100 may identify the DRX setting based on a predetermined RNTI applied to the DCI format (PDCCH) used for scheduling the PDSCH for the predetermined MAC CE. The control unit 120 may also specify the DRX setting based on a search space set and/or a search space set group that receives (or may monitor) a DCI format (PDCCH) used for scheduling a PDSCH for a specific MAC CE. The control unit 120 may also specify the DRX setting based on an identifier included in data transmitted on a PDSCH for a specific MAC CE. The control unit 120 may also specify the DRX setting based on a DCI format (PDCCH) used for scheduling a PDSCH for a specific MAC CE. Thirdly, the control information may be an uplink grant for a new transmission.

Step S103:
The control unit 120 of the UE 100 may specify a DRX setting to be controlled based on control information from among a plurality of DRX settings based on a predetermined parameter (hereinafter, appropriately referred to as a target DRX setting). For example, the control unit 120 may specify a target DRX setting according to a DCI from among a plurality of DRX settings based on a predetermined parameter applied to the DCI. The control unit 120 may specify a DRX setting from among a plurality of DRX settings based on a predetermined identifier included in data transmitted on a PDSCH scheduled using the DCI as the predetermined parameter. The UE 100 may perform at least one of the following operations to specify the target DRX setting.

(a) When the predetermined parameter is a predetermined RNTI, the control unit 120 may specify a target DRX setting corresponding to the DCI from among a plurality of DRX settings based on a predetermined RNTI applied to the DCI received by the receiving unit 112. The DCI (which may be a PDCCH) may be accompanied by a CRC (Cyclic Redundancy Check) parity bit scrambled by a predetermined RNTI assigned (set) to the UE 100 as a predetermined parameter. For example, when the control unit 120 successfully decodes the DCI, the control unit 120 may specify a target DRX setting from among a plurality of DRX settings based on the predetermined RNTI. Specifically, when the control unit 120 successfully decodes the DCI, the control unit 120 may specify a DRX setting associated with the predetermined RNTI as the target DRX setting.

The control unit 120 may perform (blind) decoding during a time when multiple DRX activation states overlap, using a predetermined RNTI associated with the DRX setting that controls the activation state. The control unit 120 may perform blind decoding during a time when multiple DRX activation states do not overlap (i.e., a time when a single DRX is activated), using a predetermined parameter associated with the DRX setting that controls the activation state. The control unit 120 may decode DCI received while the IAT is operating, using a predetermined RNTI associated with the IAT. The control unit 120 may also decode DCI received while the DRX retransmission timer (specifically, drx-RetransmissionTimerDL and/or drx-RetransmissionTimerUL) is operating, using a predetermined RNTI associated with the DRX retransmission timer.

(b) When the predetermined parameter is a search space set or a search space set group, the control unit 120 may specify a target DRX setting from among a plurality of DRX settings based on a search space set or a search space set group in which DCI as control information is arranged. That is, the control unit 120 may specify a target DRX setting from among a plurality of DRX settings based on a search space set or a search space set group that has received (or monitored) DCI (which may be a PDCCH). The control unit 120 may specify a DRX setting associated with a search space set (specifically, a search space set identifier) that has received (or monitored) DCI (which may be a PDCCH) as the target DRX setting. In addition, the control unit 120 may specify a DRX setting associated with a search space set group (specifically, a search space set group identifier) including a search space set that has received (or monitored) DCI (which may be a PDCCH) as the target DRX setting.

As described above, the control unit 120 may monitor the PDCCH in the search space set (or search space set group) associated with the DRX setting that controls the activation state during a time when multiple DRX activation states overlap. The control unit 120 may also monitor the PDCCH in the search space set (or search space set group) associated with the DRX setting that controls the activation state during a time when multiple DRX activation states do not overlap. The control unit 120 may monitor the PDCCH in the search space set (or search space set group) associated with the IAT and/or DRX retransmission timer for DCI received while the IAT and/or DRX retransmission timer is running.

(c) In the case where the predetermined parameter is a predetermined identifier included in the data transmitted on the PDSCH and/or the PUSCH, the control unit 120 may specify a target DRX setting from among a plurality of DRX settings based on a predetermined identifier included in the data transmitted on the PDSCH and/or the PUSCH. Here, the data transmitted on the PDSCH (i.e., downlink data) is also referred to as DL-SCH (Downlink Shared Channel) data. Also, the data transmitted on the PUSCH (i.e., uplink data) is also referred to as UL-SCH (Uplink Shared Channel) data. The predetermined identifier may be a radio bearer identifier. The control unit 120 may specify, for example, a DRX setting associated with a DRB ID included in the data as the target DRX setting. Also, the predetermined identifier may be an LCID. The control unit 120 may, for example, identify a DRX setting associated with an LCID included in a MAC subheader and/or a MAC CE as a target DRX setting. The predetermined identifier may be a DRX ID. The control unit 120 may identify a DRX setting associated with a DRX ID included in the data as a target DRX setting. That is, the control unit 120 may identify a target DRX setting from among a plurality of DRX settings based on a radio bearer identifier, an LCID, and/or a DRX ID.

(d) When the predetermined parameter is a DCI format, the control unit 120 may identify the target DRX setting based on the received (or monitored) DCI format (or PDCCH). The control unit 120 may identify the DRX setting associated with the DCI format (or the type of DCI format) as the target DRX setting. The control unit 120 may identify the target DRX setting based on, for example, correspondence information indicating the correspondence between the DCI format (or the type of DCI format) and the DRX setting.

Step S104:
The control unit 120 controls a target DRX setting among the multiple DRX settings based on the control information. For example, when the control information is a DCI indicating a new transmission, the control unit 120 may start or restart an IAT related to the target DRX setting.

The control unit 120 may determine whether to start or restart the IAT based on the identified DRX setting, for example, when the control information is an uplink grant for a new transmission (i.e., a DCI format used for scheduling the PUSCH). Therefore, the control unit 120 may determine whether to start or restart the IAT based on the identified DRX setting based on the uplink grant. The control unit 120 may perform the following operations, for example, as shown in FIG. 7.

Whether or not to execute the operation may be associated with a predetermined parameter (e.g., C-RNTI and/or CS-RNTI). Therefore, whether or not to execute the operation may be set individually for each predetermined parameter. If the predetermined parameter is associated with executing the operation, the control unit 120 may execute the following operation. If the predetermined parameter is associated with not executing the operation (or the predetermined parameter is not associated with executing the operation), the control unit 120 may not execute the following operation.

Step S111:
The control unit 120 may determine whether or not the skip of the uplink transmission is set. Specifically, the control unit 120 may determine whether or not the uplink transmission using the uplink resource allocated in the UE 100 is set to be skipped for one cell group when there is no data available for the uplink transmission in the uplink resource. The control unit 120 may receive, from the network 10, predetermined information (e.g., "skipUplinkTxDynamic") indicating whether or not to skip the uplink transmission for the uplink grant other than the set uplink grant when there is no data available for the uplink transmission in the uplink buffer. The control unit 120 may determine whether or not the skip of the uplink transmission is set based on the predetermined information. For example, when the control unit 120 receives an RRC message indicating that "skipUplinkTxDynamic" is "ture" (i.e., the setting of the skip of the uplink transmission), the control unit 120 may determine that the skip of the uplink transmission is set. For example, when the control unit 120 receives an RRC message in which skipUplinkTxDynamic does not indicate "ture" (i.e., setting), the control unit 120 may determine that the skip of uplink transmission is not set. Here, the skip of uplink transmission may include not generating a MAC PDU. In addition, the case where there is no data available for uplink transmission may include the case where there is no aperiodic CSI (Channel State Information, also referred to as channel state information) for the transmission in the corresponding PUSCH. In addition, the case where there is no data available for uplink transmission may include the case where the MAC PDU includes a MAC SDU with zero. In addition, the case where there is no data available for uplink transmission may include a case where the MAC PDU includes only a periodic BSR (also referred to as a buffer status report) and there is no data available for any LCG (Logical Channel Group). In addition, the case where there is no data available for uplink transmission may include a case where the MAC PDU includes only a padding BSR. For example, when a skip of uplink transmission is configured and there is no data available for uplink transmission, the control unit 120 may not generate a MAC PDU (e.g., a MAC PDU for a corresponding HARQ entity).

If the uplink transmission skip is set, the control unit 120 may execute the process of step S112. If the uplink transmission skip is not set, the control unit 120 may execute the process of step S113. The process of step S111 may be omitted.

Step S112:
The control unit 120 may determine whether there is data available for uplink transmission. For example, when there is data available for uplink transmission in the uplink buffer, the control unit 120 may execute the process of step S113. For example, when there is no data available for uplink transmission in the uplink buffer, the control unit 120 may execute the process of step S114.

Step S113:
The control unit 120 starts or re-starts the IAT. The control unit 120 may perform normal DRX operation.

Step S114:
The control unit 120 does not start or restart the IAT. The control unit 120 may stop the IAT when the IAT is running. That is, the control unit 120 may not start or restart the IAT (or may stop the IAT) when the skip of the uplink transmission is set and there is no data available for the uplink transmission. That is, the control unit 120 may not start or restart the IAT set using the DRX setting specified based on a predetermined parameter (or may stop the IAT). For example, the control unit 120 may specify the DRX setting based on a predetermined RNTI applied to a grant for the uplink transmission (for example, a DCI format used for scheduling the PUSCH), and may not start or restart the IAT set using the specified DRX setting (or may stop the IAT). Furthermore, the control unit 120 may specify the DRX setting based on the search space set and/or search space set group that has received (or may be monitored) a grant for uplink transmission, and may not start or restart the IAT set using the specified DRX setting (or may stop the IAT). Furthermore, the control unit 120 may specify the DRX setting based on a predetermined identifier included in the data in the uplink transmission (i.e., a predetermined identifier included in the data transmitted on the PUSCH), and may not start or restart the IAT set using the specified DRX setting (or may stop the IAT). Furthermore, the control unit 120 may specify the DRX setting based on a grant for uplink transmission (e.g., a DCI format used for scheduling the PUSCH), and may not start or restart the IAT set using the specified DRX setting (or may stop the IAT).

Note that although IAT has been described as an example, other operations may be performed to control the DRX operation. In the above description, IAT may be replaced with ODT.

As described above, the control unit 120 controls the DRX operation based on each of the multiple DRX settings. The receiving unit 112 receives control information from the network 10. The receiving unit 112 receives a predetermined parameter from the network 10. The control unit 120 identifies a target DRX setting from among the multiple DRX settings that is to be controlled based on the control information, based on the predetermined parameter. This allows the UE 100 to identify the target DRX setting based on the predetermined parameter, even if the UE 100 receives control information during overlapping periods of time in the activated state based on the multiple DRX settings. This allows the UE 100 to grasp the target of the control information and appropriately control the DRX operation.

Furthermore, the control information may be DCI transmitted on the PDCCH. The receiver 112 may receive the DCI transmitted by applying a predetermined parameter. The controller 120 may identify a target DRX setting corresponding to the DCI from among a plurality of DRX settings based on the predetermined parameter applied to the DCI received by the receiver 112. This makes it easier for the controller 120 to identify the target DRX setting early on, since the predetermined parameter has been applied to the DCI in the UE 100.

The specified parameter may be a specified RNTI. The control unit 120 may identify a target DRX setting from among multiple DRX settings based on the specified RNTI that successfully decoded the DCI. This allows the control unit 120 to identify the target DRX setting by decoding the DCI.

The specified parameter may be a search space set or a search space set group. The control unit 120 may identify a DRX setting from among multiple DRX settings based on the search space set or search space set group in which the DCI is placed.

The specified parameter may be a specified identifier included in the data transmitted on the PDSCH scheduled using the DCI. The control unit 120 may identify the DRX setting from among multiple DRX settings based on the specified identifier.

The predetermined parameter may be a radio bearer identifier or a logical channel identifier. These identifiers are already defined in the 3GPP technical specifications, so the impact on the specifications can be reduced.

The receiving unit 112 may also receive correspondence information from the network 10 for identifying the correspondence between the specified parameters and the DRX settings. This allows the control unit 120 to grasp the correspondence between the specified parameters and the DRX settings even if the specified parameters are not directly associated with the DRX settings.

The control information may also be an uplink grant for new transmission. The control unit 120 may determine whether to start or restart the IAT based on the target DRX setting based on the uplink grant. Because the control unit 120 does not always start or restart the IAT, power saving can be achieved compared to the case where the IAT is always started or restarted. In addition, because the control unit 120 determines the target DRX setting, DRX operation can be flexibly controlled.

In addition, the control unit 120 does not need to start or restart the DRX inactive timer when there is no data available for uplink transmission. This allows the control unit 120 to omit monitoring the PDCCH when there is no data available for uplink transmission, thereby enabling power saving.

Furthermore, the control unit 120 does not need to start or resume the IAT when a cell group is configured to skip uplink transmission using uplink resources allocated to the UE 100 when there is no data available for uplink transmission in the uplink resources, and when there is no data available for uplink transmission. This allows the control unit 120 to skip uplink transmission based on the IAT when skipping uplink transmission is permitted (configured) by the network 10, and therefore can avoid skipping uplink transmission without permission from the network 10.

(Second operation example)
A second operation example of the mobile communication system 1 will be described with reference to Fig. 6. In the second operation example, a case where the control information is a predetermined MAC CE will be described. Note that the description of the same operation as above will be omitted as appropriate.

In step 101, an operation similar to that of the first operation example may be performed.

Step S102:
The transmitting unit 211 of the base station 200 transmits a predetermined MAC CE to the UE 100 as control information for controlling the DRX operation. The receiving unit 112 of the UE 100 receives the control information from the base station 200.

The specified MAC CE is a MAC CE for stopping the ODT and/or IAT based on a DRX setting identified as a target DRX setting. The specified MAC CE may be a DRX command MAC CE or a long DRX command MAC CE. The specified MAC CE may be a MAC CE defined for stopping the ODT and/or IAT based on a DRX setting identified as a target DRX setting among multiple DRX settings configured in the UE 100. The specified MAC CE may include a specified LCID (LCID for the downlink shared channel (DL-SCH)) for identifying the specified MAC CE.

Furthermore, the transmitting unit 211 of the base station 200 may transmit the DCI by applying a predetermined parameter. The receiving unit 112 of the UE 100 may receive the DCI. The transmitting unit 211 of the base station 200 may transmit a predetermined MAC CE on the PDSCH scheduled using the DCI. The receiving unit 112 of the UE 100 may receive a predetermined MAC CE on the PDSCH scheduled using the DCI.

Step 103:
The control unit 120 of the UE 100 may specify a target DRX setting from among a plurality of DRX settings based on a predetermined parameter. The control unit 120 may perform any of the following operations.

First, the control unit 120 of the UE 100 may, for example, identify a target DRX setting corresponding to a DCI from among a plurality of DRX settings based on a specific parameter applied to the DCI, as in the first operation example. Specifically, the control unit 120 may identify, as the target DRX setting, a DRX setting corresponding to a specific parameter applied to the DCI, as a control target for a specific MAC CE transmitted on a PDSCH scheduled using the DCI.

Secondly, the control unit 120 of the UE 100 may identify the target DRX setting based on a predetermined parameter included in a predetermined MAC CE. For example, the predetermined MAC CE may include, as a predetermined parameter, an identifier for identifying the DRX setting to be controlled by the predetermined MAC CE. The predetermined parameter may be, for example, a predetermined RNTI. The predetermined parameter may be one of the predetermined parameters described above. The control unit 120 of the UE 100 may identify the DRX setting corresponding to the predetermined RNTI included in the predetermined MAC CE as the target DRX setting.

Step S104:
The control unit 120 may stop the ODT and/or IAT based on the target DRX setting based on a predetermined MAC CE.

As described above, the control information may be a specified MAC CE transmitted on the PDSCH. The control unit 120 may stop the ODT and/or IAT based on the target DRX setting based on the specified MAC CE. As a result, the UE 100 may stop the ODT and/or IAT based on the target DRX setting even if multiple DRXs are configured.

Furthermore, the specific MAC CE may include a specific LCID for identifying the specific MAC CE for stopping the ODT and IAT. This allows the control unit 120 to understand that the specific MAC CE is for stopping the ODT and IAT.

The receiving unit 112 may receive DCI transmitted by applying the specified parameters, and may receive a specified MAC CE on a PDSCH scheduled using the DCI. The control unit 120 may identify a target DRX setting corresponding to the DCI from among multiple DRX settings based on the specified parameters applied to the DCI received by the receiving unit. This allows the control unit 120 to quickly identify a target DRX setting based on the specified parameters applied to the DCI, even if the control information is signaling of a layer higher than the MAC layer.

Other Embodiments
In the above embodiment, the predetermined parameter may be data to be transmitted on the PDSCH scheduled using DCI, for example, data to be processed in a layer higher than the MAC layer. The control unit 120 of the UE 100 may specify a target DRX setting associated with the predetermined parameter in a higher layer. In this case, the control unit 120 of the UE 100 may not control the DRX operation immediately after receiving the control information. The UE 100 may control the DRX operation when specifying a target DRX setting among a plurality of DRX settings.

In the above embodiment, in the second operation example, the control unit 120 has been described as stopping the ODT and/or IAT based on the target DRX setting based on a specific MAC CE, but this is not limited to the case. For example, the control unit 120 may stop the ODT and/or IAT based on not only the target DRX setting but also each of the multiple DRX settings set in the UE 100 based on a specific MAC CE.

In the above embodiment, a mobile communication system based on NR has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system that complies with the TS of either LTE (Long Term Evolution) or another generation system of the 3GPP standard (e.g., the sixth generation). The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol termination toward the UE 100 in LTE. The mobile communication system 1 may be a system that complies with the TS of a standard other than the 3GPP standard. The base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

In the above embodiment, a mobile communication system based on NR has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system that complies with the TS of either LTE or another generation system of the 3GPP standard (e.g., the 6th generation). The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol termination toward the UE 100 in LTE. The mobile communication system 1 may be a system that complies with the TS of a standard other than the 3GPP standard.

The steps in the operations of the above-described embodiments do not necessarily have to be executed in chronological order according to the order depicted in the flow diagram or sequence diagram. For example, the steps in the operations may be executed in an order different from that depicted in the flow diagram or sequence diagram, or may be executed in parallel. Some of the steps in the operations may be deleted, and additional steps may be added to the process. Furthermore, each of the above-described operation flows is not limited to being executed separately and independently, but can be executed by combining two or more operation flows. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow.

A program may be provided that causes a computer to execute each process performed by the UE 100 or the base station 200. The program may be recorded in a computer-readable medium. Using the computer-readable medium, it is possible to install the program in the computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disk Read Only Memory). In addition, circuits that execute each process performed by the UE 100 or the base station 200 may be integrated, and at least a part of the UE 100 or the base station 200 may be configured as a semiconductor integrated circuit (chip set, SoC (System On Chip)).

In the above embodiment, "transmit" may mean performing processing of at least one layer in a protocol stack used for transmission, or may mean physically transmitting a signal wirelessly or wired. Alternatively, "transmit" may mean a combination of performing processing of at least one layer and physically transmitting a signal wirelessly or wired. Similarly, "receive" may mean performing processing of at least one layer in a protocol stack used for reception, or may mean physically receiving a signal wirelessly or wired. Alternatively, "receive" may mean a combination of performing processing of at least one layer and physically receiving a signal wirelessly or wired. Similarly, "obtain/acquire" may mean obtaining information from stored information, obtaining information from information received from other nodes, or obtaining the information by generating the information. Similarly, the terms "based on" and "depending on/in response to" do not mean "based only on" or "only in response to," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "in response to" means both "only in response to" and "at least in part on." Similarly, "include" and "comprise" do not mean including only the recited items, but may include only the recited items or may include additional items in addition to the recited items. Similarly, in this disclosure, "or" does not mean an exclusive or, but does mean an or. Furthermore, any reference to elements using designations such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and second element does not imply that only two elements may be employed therein, or that the first element must precede the second element in some manner. In this disclosure, where articles are added by translation, such as, for example, a, an, and the in English, these articles are intended to include the plural unless the context clearly indicates otherwise.

Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

(Additional Note)
The following additional features relate to the above-described embodiment.

(Appendix 1)
A communication device (100) performing a discontinuous reception (DRX) operation,
A control unit (120) that controls the DRX operation based on each of a plurality of DRX settings applied to one cell group set in the communication device;
A receiving unit (112) that receives control information for controlling the DRX operation from a network,
The receiving unit receives from the network (10) a predetermined parameter that differs for each DRX setting set in the communication device;
The control unit specifies a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.

(Appendix 2)
The communication device according to claim 1, wherein the control information is downlink control information (DCI) transmitted on a physical downlink control channel (PDCCH).

(Appendix 3)
The receiving unit receives the DCI transmitted by applying the predetermined parameter,
The control unit identifies the DRX setting to be the control target according to the DCI received by the receiving unit from among the multiple DRX settings based on the predetermined parameter applied to the DCI.

(Appendix 4)
the predetermined parameter is a predetermined Radio Network Temporary Identifier (RNTI);
The communication device according to claim 2 or 3, wherein the control unit identifies the DRX setting from among the plurality of DRX settings based on the predetermined RNTI that has successfully decoded the DCI.

(Appendix 5)
The predetermined parameter is a search space set or a search space set group,
The communication device according to any one of Supplementary Note 2 to 4, wherein the control unit identifies the DRX setting from among the plurality of DRX settings based on the search space set or search space set group in which the DCI is placed.

(Appendix 6)
The predetermined parameter is a predetermined identifier included in data transmitted on a physical downlink shared channel (PDSCH) scheduled using the DCI,
The communication device according to any one of Supplementary Note 2 to 5, wherein the control unit identifies the DRX setting from among the plurality of DRX settings based on the predetermined identifier.

(Appendix 7)
The communication device according to claim 6, wherein the predetermined parameter is a radio bearer identifier or a logical channel identifier.

(Appendix 8)
the control information is a predetermined Medium Access Control (MAC) Control Element (CE) transmitted on a Physical Downlink Shared Channel (PDSCH);
The communication device according to any one of Supplementary Note 1 to 7, wherein the control unit stops a DRX on duration timer and/or a DRX inactivity timer based on the specified DRX setting based on the predetermined MAC CE.

(Appendix 9)
The communications device according to claim 8, wherein the predetermined MAC CE includes a predetermined logical channel identifier for identifying the predetermined MAC CE for stopping the DRX on-duration timer and/or the DRX inactivity timer.

(Appendix 10)
The receiving unit is
Receive downlink control information (DCI) transmitted by applying the predetermined parameters;
receiving the predetermined MAC CE on a physical downlink shared channel (PDSCH) scheduled using the DCI;
The control unit identifies the DRX setting to be the control target according to the DCI received by the receiving unit from among the plurality of DRX settings based on the predetermined parameter applied to the DCI received by the receiving unit.

(Appendix 11)
The communication device according to any one of Supplementary Note 8 to 10, wherein the predetermined MAC CE includes, as the predetermined parameter, an identifier for identifying the DRX setting to be controlled by the predetermined MAC CE.

(Appendix 12)
The communication device according to any one of Supplementary Note 1 to 11, wherein the receiving unit receives correspondence information from the network for identifying a correspondence relationship between the predetermined parameter and the DRX setting.

(Appendix 13)
The control information is an uplink grant for a new transmission,
The communication device according to any one of Supplementary Note 1 to 12, wherein the control unit determines, based on the uplink grant, whether to start or restart a DRX inactivity timer based on the specified DRX configuration.

(Appendix 14)
14. The communications device of claim 13, wherein the controller is configured to not start or restart the DRX inactivity timer when no data is available for uplink transmission.

(Appendix 15)
The control unit is configured not to start or restart the DRX inactivity timer when the one cell group is configured to skip uplink transmission using uplink resources allocated in the communication device when there is no data available for uplink transmission in the uplink resources.

(Appendix 16)
A communication method executed in a communication device (100) performing a discontinuous reception (DRX) operation, comprising:
Controlling the DRX operation based on each of a plurality of DRX configurations applied to one cell group configured in the communication device;
receiving control information from a network (10) for controlling said DRX operation;
receiving from the network a predetermined parameter that differs for each DRX setting set in the communication device;
identifying a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.

Claims (16)

1. A communication device (100) that performs discontinuous reception (DRX) operation,
   A control unit (120) that controls the DRX operation based on each of a plurality of DRX settings applied to one cell group set in the communication device;
   A receiving unit (112) that receives control information for controlling the DRX operation from a network,
   The receiving unit receives, from the network (10), a predetermined parameter that differs for each DRX setting set in the communication device;
   The control unit identifies a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.
2. The communication device according to claim 1 , wherein the control information is downlink control information (DCI) transmitted on a physical downlink control channel (PDCCH).
3. The receiving unit receives the DCI transmitted by applying the predetermined parameter,
   The communication device according to claim 2 , wherein the control unit identifies, from among the plurality of DRX settings, the DRX setting to be the control target according to the DCI received by the receiving unit, based on the predetermined parameter applied to the DCI.
4. the predetermined parameter is a predetermined Radio Network Temporary Identifier (RNTI);
   The communication device according to claim 2 , wherein the control unit is configured to identify the DRX setting from among the plurality of DRX settings based on the predetermined RNTI that has successfully decoded the DCI.
5. The predetermined parameter is a search space set or a search space set group,
   The communication device according to claim 2 , wherein the control unit is configured to identify the DRX configuration from among the plurality of DRX configurations based on the search space set or search space set group in which the DCI is arranged.
6. The predetermined parameter is a predetermined identifier included in data transmitted on a physical downlink shared channel (PDSCH) scheduled using the DCI,
   The communication device according to claim 2 , wherein the control unit identifies the DRX setting from among the plurality of DRX settings based on the predetermined identifier.
7. The communication device according to claim 6 , wherein the predetermined parameter is a radio bearer identifier or a logical channel identifier.
8. the control information is a predetermined Medium Access Control (MAC) Control Element (CE) transmitted on a Physical Downlink Shared Channel (PDSCH);
   The communication device according to claim 1 , wherein the control unit stops a DRX on-duration timer and/or a DRX inactivity timer based on the specified DRX setting based on the predetermined MAC CE.
9. The communication device according to claim 8 , wherein the predetermined MAC CE includes a predetermined logical channel identifier for identifying the predetermined MAC CE for stopping the DRX on-duration timer and/or the DRX inactivity timer.
10. The receiving unit is
    Receive downlink control information (DCI) transmitted by applying the predetermined parameters;
    receiving the predetermined MAC CE on a physical downlink shared channel (PDSCH) scheduled using the DCI;
    The communication device according to claim 8 or 9, wherein the control unit identifies, from among the plurality of DRX settings, the DRX setting to be the control target according to the DCI received by the receiving unit, based on the predetermined parameter applied to the DCI.
11. The communication device according to claim 8 or 9, wherein the predetermined MAC CE includes, as the predetermined parameter, an identifier for identifying the DRX setting to be controlled by the predetermined MAC CE.
12. The communication device according to claim 1 , wherein the receiving unit receives correspondence information for identifying a correspondence relationship between the predetermined parameter and the DRX setting from the network.
13. The control information is an uplink grant for a new transmission,
    The communication device according to claim 1 , wherein the control unit determines, based on the uplink grant, whether to start or restart a DRX inactivity timer based on the specified DRX setting.
14. The communication device of claim 13 , wherein the controller is configured to not start or restart the DRX inactivity timer if no data is available for uplink transmission.
15. The communication device according to claim 14, wherein the control unit does not start or restart the DRX inactivity timer when the one cell group is configured to skip uplink transmission using an uplink resource allocated in the communication device when there is no data available for uplink transmission in the uplink resource.
16. A communication method executed in a communication device (100) performing a discontinuous reception (DRX) operation, comprising:
    Controlling the DRX operation based on each of a plurality of DRX configurations applied to one cell group configured in the communication device;
    receiving control information from a network (10) for controlling said DRX operation;
    receiving from the network a predetermined parameter that differs for each DRX setting set in the communication device;
    identifying a DRX setting to be controlled based on the control information from among the plurality of DRX settings based on the predetermined parameter.

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