Base station, communication terminal, communication method, control method, and program

Abstract

To provide a base station capable of achieving flexible DRX control in a communication terminal.SOLUTION: A base station according to the present disclosure includes a management unit configured to manage a plurality of DRX parameter sets used for controlling discontinuous reception in a communication terminal, and a communication unit configured to transmit, to the communication terminal, a notification message including information indicating a first DRX parameter set to be applied to the communication terminal among the plurality of DRX parameter sets.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a base station, a communication terminal, a communication method, a control method, and a program. [Background technology]

[0002] To reduce the power consumption of communication terminals that perform wireless communication, discontinuous reception (DRX) is performed in the communication terminals. DRX is an operation in which the communication terminal alternates between an on period during which it receives a signal and a sleep period during which it performs power-saving operation.

[0003] Patent Document 1 discloses the configuration of a wireless communication system that performs carrier aggregation to aggregate component carriers of a macro cell and component carriers of small cells. The wireless communication system of Patent Document 1 discloses that a reduction in power consumption in a user terminal is achieved by applying different DRX controls to each component carrier. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-229950 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 discloses that a wireless communication system performs DRX control for each component carrier, that is, for each cell. However, in order to achieve further power saving in the future, there is a demand for flexible DRX control to be realized in communication terminals.

[0006] In view of the above-described problems, an object of the present disclosure is to provide a base station, a communication terminal, a communication method, a control method, and a program that enable flexible DRX control to be realized in a communication terminal. [Means for solving the problem]

[0007] A base station according to the present disclosure includes a management unit that manages a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal, and a communication unit that transmits to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets.

[0008] A communication terminal according to the present disclosure includes a communication unit that receives, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception, and a control unit that performs discontinuous reception in accordance with the first DRX parameter set.

[0009] A communication method performed in a base station according to the present disclosure manages a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal, and transmits a notification message to the communication terminal including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets.

[0010] The control method according to the present disclosure receives a notification message from a base station including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception, and performs discontinuous reception in accordance with the first DRX parameter set.

[0011] The program of the present disclosure causes a computer to manage a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal, and to transmit to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets. [Effects of the Invention]

[0012] The present disclosure makes it possible to provide a base station, a communication terminal, a communication method, a control method, and a program that enable flexible DRX control to be realized in a communication terminal. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows an example configuration of a base station according to the present disclosure. [Figure 2] FIG. 2 is a diagram showing the flow of processing in a communication method executed in a base station. [Figure 3] Figure 3 shows an example configuration of a gNB according to the present disclosure. [Figure 4] FIG. 4 shows an example of the configuration of a UE. [Figure 5] Figure 5 shows the RRC connection establishment procedure between the UE and the gNB. [Figure 6] FIG. 6 shows information elements included in the RRC Setup message. [Figure 7] Figure 7 illustrates an example of measuring communication quality in a gNB. [Figure 8] FIG. 8 shows the flow of the DRX parameter notification process. [Figure 9] FIG. 9 is a block diagram showing an example configuration of a base station and a gNB. [Figure 10] FIG. 10 is a block diagram showing an example of the configuration of a UE. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Embodiment 1) FIG. 1 shows a configuration example of a base station 10 according to the present disclosure. The base station 10 may be a computer device operated by a processor executing a program stored in a memory. The base station 10 may be an evolved Node B (eNB) or a gNB, the specifications of which are defined by the 3GPP (3rd Generation Partnership Project). The base station 10 may also be a base station system including a radio unit (Radio Unit: DU) and a control unit (Distributed Unit: DU or Centralized Unit: CU) that performs baseband processing. The base station system may be referred to as a Radio Access Network (RAN). The base station 10 may also be a communication device that constitutes the RAN.

[0015] The base station 10 has a management unit 11 and a communication unit 12. The management unit 11 and the communication unit 12 may be software or modules that perform processing by a processor executing a program stored in a memory. Alternatively, the management unit 11 and the communication unit 12 may be hardware such as a circuit or a chip. Alternatively, the management unit 11 may be memory within the base station 10 or attached to the base station 10.

[0016] The management unit 11 may be used as a means for managing information, and the communication unit 12 may be used as a means for transmitting or receiving information.

[0017] The management unit 11 manages a plurality of DRX (Discontinuous Reception) parameter sets used to control discontinuous reception in a communication terminal. The communication terminal may be a computer device operated by a processor executing a program stored in a memory. The communication terminal may be, for example, a UE (User Equipment) whose specifications are defined by 3GPP. Specifically, the communication terminal may be a smartphone terminal, a tablet terminal, an IoT (Internet of Things) terminal, or the like. Discontinuous reception is a receiving operation performed in a communication terminal to reduce power consumption in the communication terminal. Specifically, the communication terminal turns on the power in accordance with a time slot containing information to be received, and turns off the power at other times.

[0018] The DRX parameter set includes at least one parameter used in discontinuous reception. The parameter may be, for example, a parameter set in or applied to a communication terminal. For example, the DRX parameter set may include a setting value of at least one timer used in discontinuous reception. The setting value of the timer may be referred to as a parameter value or setting value. The DRX parameter set may be a parameter set that is a candidate for application to a communication terminal. The DRX parameter set may be referred to as a DRX parameter category, DRX parameter group, DRX parameter type, DRX parameter class, etc.

[0019] Managing a plurality of DRX parameter sets may be rephrased as memorizing, recording, storing, etc., a plurality of DRX parameter sets. The management unit 11 may manage DRX parameter sets input from an administrator who manages the base station 10. Alternatively, the management unit 11 may manage predetermined DRX parameter sets. Alternatively, the management unit 11 may receive DRX parameter sets from another device that manages or calculates DRX parameter sets.

[0020] The communication unit 12 transmits to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among a plurality of DRX parameter sets. The information indicating the first DRX parameter set may be information for identifying the first DRX parameter set. The information for identifying the DRX parameter set may be, for example, an index value, an identifier, or the like. The index value or the identifier and the DRX parameter set may be managed in association with each other in the management unit 11.

[0021] The notification message may be transmitted to the communication terminal as a response message to a request message received from the communication terminal. Alternatively, the notification message may be a message transmitted in response to a message received from a device other than the communication terminal, or may be a message transmitted without a specific trigger. The device other than the communication terminal may be, for example, a core network device or a core network node. Furthermore, the notification message may be transmitted to the communication terminal periodically.

[0022] The notification message is used to notify the communication terminal of a first DRX parameter set to be configured or applied to the communication terminal. When the communication terminal receives information indicating the first DRX parameter set, the communication terminal may set values ​​of parameters included in the first DRX parameter set. Alternatively, when the communication terminal receives the first DRX parameter set, the communication terminal may update or replace values ​​of parameters that have already been set with values ​​of the first DRX parameter set.

[0023] 2 is a diagram showing the processing flow of the communication method executed in base station 10. First, management unit 11 manages a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal (S11). Next, communication unit 12 transmits to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets (S12).

[0024] As described above, base station 10 notifies a communication terminal of a first DRX parameter set to be applied to the communication terminal from among multiple DRX parameter sets. Base station 10 may set the first DRX parameter set in order to change the DRX parameters to be set in the communication terminal. As a result, the communication terminal changes the currently set DRX parameters to the values ​​of the first DRX parameter set notified by base station 10, thereby performing discontinuous reception in accordance with the new parameter values. In other words, by setting the values ​​of the DRX parameters notified by base station 10, the communication terminal can perform discontinuous reception while flexibly changing the values ​​of the DRX parameters.

[0025] (Embodiment 2) Figure 3 shows an example configuration of a gNB 20 according to the present disclosure. The gNB 20 corresponds to the base station 10 in Figure 1. The gNB 20 has a management unit 21, a communication unit 22, and a control unit 23. The management unit 21 corresponds to the management unit 11 in Figure 1. The communication unit 22 corresponds to the communication unit 12 in Figure 1. In explaining Figure 3, detailed explanations of configurations, functions, processing, operations, etc. that are the same as those of the base station 10 in Figure 1 will be omitted. Here, the control unit 23 may be used as a means for controlling processing, operations, etc. in the gNB 20.

[0026] The gNB 20 performs wireless communication with the UE 30 using a wireless communication method called 5G (5th Generation). 5G specifications are defined by 3GPP. The UE 30 corresponds to a communication terminal.

[0027] The management unit 21 manages a plurality of DRX parameter sets. Here, an example of the DRX parameter set managed by the management unit 21 will be described. The management unit 21 manages the setting value of at least one DRX parameter out of a plurality of DRX parameters included in the DRX parameter set shown below. The setting value may be referred to as a timer value. -drx-onDurationTimer -drx-InactivityTimer -drx-HARQ-RTT-TimerDL / UL -drx-RetransmissionTimerDL / UL -drx-LongCycleStartOffset -shortDRX -drx-SlotOffset

[0028] drx-onDurationTimer is a value indicating a period during which a signal is received from the start of a DRX cycle. For example, drx-onDurationTimer may be a time for monitoring a PDCCH (Physical Downlink Control Channel). A DRX cycle is composed of a reception period during which UE 30 receives a signal and a non-reception period during which UE 30 does not receive a signal. The reception period may be referred to as an active period. The non-reception period may be referred to as a sleep period. UE 30 receives a signal during the reception period in the repeated DRX cycle. In the present disclosure, the term "time" may be rephrased as "period."

[0029] The drx-InactivityTimer is a value indicating a period after the UE 30 receives a PDCCH instructing transmission of user data in uplink or downlink. Specifically, the drx-InactivityTimer may be a time period that the UE 30 waits after decoding a PDCCH before receiving or decoding the next PDCCH.

[0030] drx-HARQ-RTT-TimerDL / UL is a value indicating the minimum time until a downlink HARQ retransmission is performed and the minimum time until an uplink HARQ retransmission grant is transmitted.

[0031] drx-RetransmissionTimerDL / UL is a value indicating the maximum time to receive a downlink retransmission and the maximum time to receive an uplink retransmission grant.

[0032] drx-LongCycleStartOffset is a value indicating the length of the Long DRX cycle and drx-startOffset, which defines the subframe in which the DRX cycle starts.

[0033] shortDRX is a value indicating the length of a short DRX cycle, and may be indicated using drx-shortCycle.

[0034] drx-SlotOffset is a value that indicates the delay before starting drx-onDurationTimer.

[0035] The management unit 21 manages a combination of setting values ​​of at least one of the following DRX parameters. A combination of setting values ​​of the DRX parameters corresponds to a DRX parameter set. The setting value may be a value representing the number of time slots. -drx-onDurationTimer -drx-InactivityTimer -drx-HARQ-RTT-TimerDL / UL -drx-RetransmissionTimerDL / UL -drx-LongCycleStartOffset -shortDRX -drx-SlotOffset

[0036] A combination of DRX parameter setting values ​​may be associated with identification information. The identification information may be, for example, an index value. That is, by specifying an index value, the DRX parameter setting value associated with the index value is identified. The management unit 21 may manage a plurality of pairs of information of combinations of index values ​​and DRX parameter setting values.

[0037] Furthermore, the management unit 21 may manage the DRX parameter set currently set in the UE 30 .

[0038] The communication unit 22 transmits the index value and a combination of DRX parameter setting values ​​associated with the index value to the UE 30. The communication unit 22 transmits a plurality of pieces of pair information to the UE 30. As a result, the UE 30 and the gNB 20 share the index value and the combination of DRX parameter setting values ​​associated with the index value. After the communication unit 22 shares the index value and the combination of DRX parameter setting values ​​associated with the index value with the UE 30, the communication unit 22 may transmit only the index value to the UE 30. As a result, the gNB 20 specifies the setting values ​​of the DRX parameters used for performing DRX in the UE 30.

[0039] The control unit 23 controls the execution of DRX in the UE 30 in accordance with values ​​selected or specified as setting values ​​of DRX parameters used for the execution of DRX in the UE 30. For example, the control unit 23 may control the timing of transmitting a signal to the UE 30 in accordance with a DRX cycle determined based on the setting values ​​of the DRX parameters.

[0040] 4 shows an example configuration of UE 30. UE 30 has a communication unit 31, a management unit 32, and a control unit 33. The communication unit 31, the management unit 32, and the control unit 33 may be software or modules that perform processing by a processor executing a program stored in a memory. Alternatively, the communication unit 31, the management unit 32, and the control unit 33 may be hardware such as a circuit or a chip. The communication unit 31 may be used as a means for transmitting or receiving information. The management unit 32 may be used as a means for managing information. The control unit 33 may be used as a means for controlling processing, operation, etc. in UE 30.

[0041] The communication unit 31 receives an index value and a combination of DRX parameter setting values ​​associated with the index value from the gNB 20. The management unit 32 manages the index value received by the communication unit 31 and the combination of DRX parameter setting values ​​associated with the index value. For example, the management unit 32 may store, save, preserve, or record the index value and the combination of DRX parameter setting values ​​associated with the index value in a memory within the UE 30 or a memory external to the UE 30.

[0042] Furthermore, the communication unit 31 receives only the index value from the gNB 20. In this case, the control unit 33 identifies a combination of setting values ​​of DRX parameters associated with the index value received by the communication unit 31. For example, the control unit 33 extracts the setting values ​​of the DRX parameters associated with the index value from the management unit 32. The control unit 33 performs DRX in accordance with the identified setting values ​​of the DRX parameters. For example, the control unit 33 may perform signal reception processing at a timing determined based on the setting values ​​of the DRX parameters.

[0043] 5 shows the procedure for establishing an RRC (Radio Resource Control) connection between UE 30 and gNB 20. RRC is a protocol for controlling radio resources. An RRC connection is established for each UE. Messages transmitted between UE 30 and gNB 20 to establish an RRC connection, and messages transmitted in accordance with the RRC protocol, are referred to as RRC messages.

[0044] First, UE30 transmits an RRCSetup Request message to gNB20 (S21). Next, gNB20 transmits an RRCSetup message to UE30 (S22). The RRCSetup message includes an index value and a combination of DRX parameter setting values ​​associated with the index value. Next, UE30 transmits an RRCSetup Complete message to gNB20. The RRCSetup Complete message may be a response message to the RRCSetup message.

[0045] Here, the RRC Setup message will be described in detail. The RRC Setup message may be used, for example, to establish an SRB (Signaling Radio Bearer) 1. Fig. 6 shows information elements (IEs) included in the RRC Setup message.

[0046] As shown in FIG. 6, the RRC Setup message includes a CellGroupConfig IE. The CellGroupConfig IE is used to configure an MCG (Master Cell Group) or an SCG (Secondary Cell Group). A cell group includes one or more cells formed by a gNB or the like. The MCG includes a primary cell. The SCG includes cells other than the primary cell. The primary cell is a component carrier that connects with the UE in carrier aggregation.

[0047] Furthermore, as shown in Fig. 6, the CellGroupConfig IE includes a MAC-CellGroupConfig IE. The MAC-CellGroupConfig IE includes MAC parameters available to UE 30. Furthermore, as shown in Fig. 6, the MAC-CellGroupConfig IE includes a drx-Multi-Config IE. The drx-Multi-Config IE includes, for example, values ​​of parameters used for performing DRX or controlling DRX.

[0048] Furthermore, the drx-Multi-Config IE includes the following DRX parameters, as shown in FIG. -drx-ConfigIndex -drx-onDurationTimer -drx-InactivityTimer -drx-HARQ-RTT-TimerDL / UL -drx-RetransmissionTimerDL / UL -drx-LongCycleStartOffset -shortDRX -drx-SlotOffset

[0049] drx-ConfigIndex is an index value that identifies a combination of the configuration values ​​of drx-onDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL / UL, drx-RetransmissionTimerDL / UL, drx-LongCycleStartOffset, shortDRX, and drx-SlotOffset. Here, if there are multiple combinations of configuration values ​​such as drx-onDurationTimer, the drx-Multi-Config IE may include multiple combinations of drx-ConfigIndex and configuration values ​​such as drx-onDurationTimer. The drx-ConfigIndex and the configuration values ​​such as drx-onDurationTimer that follow the drx-ConfigIndex are associated with each other.

[0050] The drx-ConfigIndex is an index value, and may be used as a parameter value included in the DRX parameters, or may be used as a parameter value different from the DRX parameters.

[0051] When UE 30 receives the RRCSetup message, UE 30 manages drx-ConfigIndex in association with the setting values ​​of drx-onDurationTimer and the like that follow drx-ConfigIndex. That is, when a value of drx-ConfigIndex is specified, UE 30 can identify the setting values ​​of the DRX parameters associated with the specified drx-ConfigIndex.

[0052] Here, when establishing an RRC connection, UE 30 may apply the setting values ​​of the DRX parameters associated with a specific value of drx-ConfigIndex among multiple drx-ConfigIndex included in the RRCSetup message. The specific value may be, for example, a value such as 0. The specific value may be used as, for example, an initial value. In other words, after establishing an RRC connection, UE 30 may perform DRX according to the setting values ​​of the DRX parameters associated with the initial value of drx-ConfigIndex.

[0053] 5 has been described as an example in which the gNB20 includes the drx-ConfigIndex and the configuration values ​​of the DRX parameters associated with the drx-ConfigIndex in the RRCSetup message, but the gNB20 may use a message other than the RRCSetup message. For example, the gNB20 may include the drx-ConfigIndex and the configuration values ​​of the DRX parameters associated with the drx-ConfigIndex in the RRCReconfiguration message. Alternatively, the gNB20 may include the drx-ConfigIndex and the configuration values ​​of the DRX parameters associated with the drx-ConfigIndex in the RRCReestablishment message. Alternatively, the gNB20 may include the drx-ConfigIndex and the configuration values ​​of the DRX parameters associated with the drx-ConfigIndex in the RRCReestablishment message.

[0054] 7 illustrates an example of measuring communication quality in the gNB 20. First, the UE 30 transmits a PUCCH (Physical Uplink Control Channel) including UCI (Uplink Control Information) to the gNB 20 (S31). The UCI may be, for example, an ACK (Acknowledgement) or a NACK (Negative ACK) for downlink data transmitted from the gNB 20 to the UE 30. Alternatively, the UCI may be a scheduling request requesting the gNB 20 to allocate resources.

[0055] Next, the gNB 20 performs quality measurement regarding communication with the UE 30 (S32). The quality measurement may be performed by the management unit 21 or the control unit 23. For example, the gNB 20 may measure the block error rate (BLER) of UCI included in the PUCCH as quality information. The quality information may be information indicating the communication status between the gNB 20 and the UE 30. The BLER may be a value indicating the ratio of erroneously decoded UCI to correctly decoded UCI. The gNB 20 may measure the BLER every time it receives a PUCCH, may measure the BLER using a PUCCH received at a predetermined timing, or may measure the BLER using a PUCCH received at an arbitrary timing. Alternatively, the gNB 20 may measure the BLER using a signal other than the PUCCH, for example, a physical uplink shared channel (PUSCH). Alternatively, the gNB 20 may acquire the BLER measured by the UE 30 using a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH). That is, gNB20 may receive the BLER measurement results transmitted from UE30.

[0056] The gNB 20 may manage the measured quality information or the quality information received from the UE 30 in the management unit 21.

[0057] 8 shows the flow of the DRX parameter notification process. First, the gNB 20 determines the setting values ​​of the DRX parameters to be applied to the UE 30 (S41). The gNB 20 may determine the setting values ​​of the DRX parameters to be applied to the UE 30 based on the quality information measured in step S32 of FIG. 7.

[0058] For example, when the BLER is greater than a predetermined reference value, the control unit 23 may determine the setting values ​​of the DRX parameters so as to decrease the communication timing of the UE 30. That is, when the BLER is smaller than a predetermined reference value, the control unit 23 may determine the setting values ​​of the DRX parameters so as to increase the communication timing of the UE 30. When the BLER is the same value as the predetermined reference value, the communication timing of the UE 30 may be decreased or increased, or the current communication timing of the UE 30 may be maintained.

[0059] Alternatively, the control unit 23 may compare an average value of the BLER measured multiple times with a predetermined reference value. Alternatively, when the BLER value measured multiple times is on an increasing trend, the control unit 23 may determine setting values ​​of the DRX parameters so as to decrease the communication timing of the UE 30. In other words, when the BLER value measured multiple times is on a decreasing trend, the control unit 23 may determine setting values ​​of the DRX parameters so as to increase the communication timing of the UE 30.

[0060] Alternatively, when the BLER or the average value of the BLER is greater than a predetermined reference value, the control unit 23 may determine the setting values ​​of the DRX parameters so as to increase the retransmission timing in the UE 30. In other words, when the BLER or the average value of the BLER is smaller than a predetermined reference value, the control unit 23 may determine the setting values ​​of the DRX parameters so as to decrease the retransmission timing in the UE 30.

[0061] Alternatively, the gNB 20 may determine the setting values ​​of the DRX parameters to be applied to the UE 30 based on a 5QI (5G network Quality of service class Identifier). The 5QI is information similar to a QCI (Quality Class Identifier) ​​in 4G. The 5QI may be service information to be applied to the UE 30. The 5QI is a Quality of Service (QoS) class set for each flow. Requirements such as priority, delay time, and error rate may be defined for the 5QI. The 5QI is identified by identification information. In other words, different QoS class requirements are defined for each identification information.

[0062] The control unit 23 may determine the setting values ​​of the DRX parameters so as to increase the communication timing of the UE 30 as the quality indicated by each QoS requirement of the multiple 5QIs becomes higher. Alternatively, the management unit 21 may manage the identification information of the 5QI in association with the index value associated with the setting values ​​of the DRX parameters. In this case, after identifying the 5QI of the flow used by the UE 30, the control unit 23 may apply to the UE 30 the setting values ​​of the DRX parameters further associated with the index value associated with the identified 5QI.

[0063] Here, determining the setting values ​​of the DRX parameters so as to increase the communication timing may mean, for example, selecting a DRX parameter set including a drx-onDurationTimer whose value is longer than the currently set value of the drx-onDurationTimer. Alternatively, determining the setting values ​​of the DRX parameters so as to increase the communication timing may mean selecting a DRX parameter set including a drx-InactivityTimer whose value is shorter than the currently set value of the drx-InactivityTimer. Alternatively, determining the setting values ​​of the DRX parameters so as to increase the communication timing may mean selecting a DRX parameter set including a drx-RetransmissionTimerDL / UL whose value is longer than the currently set value of the drx-RetransmissionTimerDL / UL. Alternatively, determining the setting values ​​of the DRX parameters so as to increase the communication timing may mean selecting a DRX parameter set which increases the number of communication timings compared to the currently set DRX parameter set.

[0064] Furthermore, control unit 23 may determine setting values ​​of DRX parameters to be applied to UE 30 using a learning model generated by performing machine learning. The learning model may receive, for example, at least one of quality information and service information related to communication with UE 30. Furthermore, the learning model may output a DRX parameter set using, as training data, an appropriate DRX parameter set in the quality information related to communication with UE 30 and an appropriate DRX parameter set in the service information of UE 30.

[0065] Next, the gNB 20 transmits a PDSCH including an index value associated with the determined DRX parameter configuration value to the UE 30 (S42). The index value is the value of drx-ConfigIndex. For example, the index value may be set in a MAC (Medium Access Control)-CE (Control Element) included in the PDSCH.

[0066] Next, upon receiving the PDSCH including the index value, UE 30 transmits UCI indicating an Ack to gNB 20 (S43). Upon receiving the PDSCH including the index value, control unit 33 of UE 30 identifies the setting values ​​of DRX parameters associated with the index value, using information managed by management unit 32. Furthermore, after transmitting the UCI, control unit 33 updates the setting values ​​of the currently set DRX parameters to the identified setting values ​​of the DRX parameters. "Updating" may also be interpreted as "changing" or "switching." When control unit 33 updates the setting values ​​of the DRX parameters, it may update the DRX parameter sets managed by management unit 32 as currently set in UE 30 to the updated DRX parameter sets.

[0067] Furthermore, the control unit 33 does not need to change the setting values ​​of parameters that are not included in the identified DRX parameters from the currently set DRX parameter setting values.

[0068] When gNB20 receives UCI indicating ACK, it performs DRX control for UE30 in accordance with the DRX parameters determined in step S41.

[0069] Furthermore, UE 30 may switch the DRX parameter setting value immediately after transmitting the UCI, or may switch the DRX parameter setting value after a predetermined period has elapsed after transmitting the UCI. The predetermined period may be, for example, a predetermined number of time slots. Specifically, UE 30 may switch the DRX parameter setting value after a predetermined number of time slots have elapsed, based on the time slot in which the UCI was transmitted.

[0070] Furthermore, the gNB20 may switch the DRX parameter setting values ​​immediately after receiving the UCI, or may switch the DRX parameter setting values ​​after a predetermined period has elapsed after receiving the UCI. Specifically, the gNB20 may switch the DRX parameter setting values ​​after a predetermined number of time slots have elapsed, based on the time slot in which the UCI was received. If the gNB20 switches the DRX parameter setting values ​​immediately after the UE30 transmits the UCI, the gNB20 switches the DRX parameter setting values ​​immediately after receiving the UCI. If the gNB20 switches the DRX parameter setting values ​​after a predetermined period has elapsed after the UE30 transmits the UCI, the gNB20 switches the DRX parameter setting values ​​after a predetermined period has elapsed after receiving the UCI.

[0071] As described above, the gNB 20 shares the index value and the DRX parameter setting value associated with the index value with the UE 30. Furthermore, when the gNB 20 decides to change the DRX parameter setting value in the UE 30, the gNB 20 notifies the UE 30 of the index value associated with the changed DRX parameter setting value. This allows the gNB 20 to flexibly change the DRX parameter setting value in the UE 30.

[0072] Furthermore, the gNB 20 can notify each of a plurality of UEs of DRX parameter setting values. As a result, the gNB 20 can notify each UE of more appropriate DRX parameter setting values ​​according to the communication status or service information of the UE.

[0073] FIG. 9 is a block diagram showing an example configuration of a base station 10 and a gNB 20 (hereinafter referred to as the base station 10, etc.). Referring to FIG. 9, the base station 10, etc. includes an RF transceiver 1001, a network interface 1003, a processor 1004, and a memory 1005. The RF transceiver 1001 performs analog RF signal processing to communicate with UEs. The RF transceiver 1001 may include multiple transceivers. The RF transceiver 1001 is coupled to an antenna 1002 and the processor 1004. The RF transceiver 1001 receives modulation symbol data (or OFDM symbol data) from the processor 1004, generates a transmit RF signal, and provides the transmit RF signal to the antenna 1002. The RF transceiver 1001 also generates a baseband receive signal based on the receive RF signal received by the antenna 1002 and provides the baseband receive signal to the processor 1004.

[0074] The network interface 1003 is used to communicate with network nodes (e.g., other core network nodes) and may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series.

[0075] The processor 1004 performs data plane processing and control plane processing, including digital baseband signal processing for wireless communication.

[0076] The processor 1004 may include multiple processors, such as a modem processor (e.g., a DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., a CPU or an MPU) that performs control plane processing.

[0077] The memory 1005 is configured by a combination of volatile memory and nonvolatile memory. The memory 1005 may include multiple physically independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The nonvolatile memory is, for example, Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. The memory 1005 may include storage located remotely from the processor 1004. In this case, the processor 1004 may access the memory 1005 via the network interface 1003 or an I / O interface (not shown).

[0078] The memory 1005 may store software modules (computer programs) including instructions and data for performing processing by the base station 10, etc., described in the above-described embodiments. In some implementations, the processor 1004 may be configured to read and execute the software modules from the memory 1005, thereby performing processing by the base station 10, etc., described in the above-described embodiments.

[0079] 10 is a block diagram showing an example configuration of UE 30. A radio frequency (RF) transceiver 1101 performs analog RF signal processing for communication with gNB 20. The analog RF signal processing performed by RF transceiver 1101 includes frequency up-conversion, frequency down-conversion, and amplification. RF transceiver 1101 is coupled to an antenna 1102 and a baseband processor 1103. That is, RF transceiver 1101 receives modulation symbol data (or OFDM symbol data) from baseband processor 1103, generates a transmit RF signal, and provides the transmit RF signal to antenna 1102. RF transceiver 1101 also generates a baseband receive signal based on the receive RF signal received by antenna 1102 and provides it to baseband processor 1103.

[0080] The baseband processor 1103 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of transmission formats (transmission frames), (d) transmission path coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) using Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management for Layer 1, Layer 2, and Layer 3.

[0081] The baseband processor 1103 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1104, which will be described later.

[0082] The application processor 1104 is also referred to as a CPU, an MPU, a microprocessor, or a processor core. The application processor 1104 may include multiple processors (multiple processor cores). The application processor 1104 executes a system software program (operating system (OS)) and various application programs (e.g., a call application, a web browser, a mailer, a camera operation application, and a music playback application) read from the memory 1106 or a memory not shown, thereby realizing various functions of the UE 30.

[0083] In some implementations, the baseband processor 1103 and the application processor 1104 may be integrated on a single chip, as indicated by the dashed line (1105) in Figure 10. In other words, the baseband processor 1103 and the application processor 1104 may be implemented as a single System on Chip (SoC) device 1105. An SoC device may also be called a system Large Scale Integration (LSI) or a chipset.

[0084] The memory 1106 is volatile memory, nonvolatile memory, or a combination thereof. The memory 1106 may include multiple physically independent memory devices. The volatile memory may be, for example, static random access memory (SRAM), dynamic RAM (DRAM), or a combination thereof. The nonvolatile memory may be mask read only memory (MROM), electrically erasable programmable ROM (EEPROM), flash memory, a hard disk drive, or any combination thereof. For example, the memory 1106 may include an external memory device accessible from the baseband processor 1103, the application processor 1104, and the SoC 1105. The memory 1106 may also include an internal memory device integrated within the baseband processor 1103, the application processor 1104, or the SoC 1105. Furthermore, the memory 1106 may include memory within a universal integrated circuit card (UICC).

[0085] The memory 1106 may store software modules (computer programs) including instructions and data for performing the processes described in the above-described embodiments by the UE 30. In some implementations, the baseband processor 1103 or the application processor 1104 may be configured to read and execute the software modules from the memory 1106, thereby performing the processes of the UE 30 described in the above-described embodiments.

[0086] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0087] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0088] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0089] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a management unit that manages a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal; a communication unit that transmits to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets. (Appendix 2) The communication unit 2. The base station of claim 1, further comprising: a base station configured to transmit identification information associated with the first DRX parameter set to the communication terminal; (Appendix 3) The communication unit 3. The base station according to claim 2, wherein the base station transmits a Media Access Control Element (MAC CE) including the identification information to the communication terminal. (Appendix 4) The communication unit 4. The base station according to claim 1, wherein the base station transmits an RRC (Radio Resource Control) message including the plurality of DRX parameter sets to the communication terminal. (Appendix 5) The communication unit 5. The base station according to claim 4, wherein the base station transmits the DRX parameter set and identification information associated with the DRX parameter set to the communication terminal. (Appendix 6) 6. The base station according to claim 1, further comprising: a control unit that controls discontinuous reception in the communication terminal based on the first DRX parameter set after receiving a response message to the notification message from the communication terminal. (Appendix 7) The control unit The base station described in Supplementary Note 6, which controls discontinuous reception in the communication terminal based on the first DRX parameter set after a predetermined time slot has elapsed, based on the time slot in which the response message was received. (Appendix 8) The control unit 8. The base station according to claim 6, wherein the DRX parameter set to be applied to the communication terminal is switched based on a service usage status in the communication terminal or a communication status in the communication terminal. (Appendix 9) a communication unit that receives, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception; a control unit that performs discontinuous reception in accordance with the first DRX parameter set. (Appendix 10) Manage a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal; A communication method executed in a base station, comprising transmitting, to the communication terminal, a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets. (Appendix 11) receiving, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception; A control method executed in a communication terminal, which performs discontinuous reception in accordance with the first DRX parameter set. (Appendix 12) Manage a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal; A program that causes a computer to execute the following: transmitting, to the communication terminal, a notification message including information indicating a first DRX parameter set to be applied to the communication terminal, out of the plurality of DRX parameter sets. (Appendix 13) receiving, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception; A program that causes a computer to execute the following: performing discontinuous reception in accordance with the first DRX parameter set.

[0090] Some or all of the elements (e.g., configurations and functions) described in Supplementary Notes 2 to 8 that are dependent on Supplementary Notes 1 may also be dependent on Supplementary Notes 9 to 13 in the same dependency relationship as Supplementary Notes 2 to 8. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0091] 10 base station 11 Management Department 12 Communications Department 20 gNB 21 Management Department 22 Communications Department 23 Control Unit 30UE 31 Communications Department 32 Management Department 33 Control Unit

Claims

1. a management unit that manages a plurality of DRX parameter sets used to control discontinuous reception in a communication terminal; a communication unit configured to transmit to the communication terminal a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets.

2. The communication unit The base station according to claim 1 , further comprising: transmitting identification information associated with the first DRX parameter set to the communication terminal.

3. The communication unit The base station according to claim 2 , wherein the base station transmits a Media Access Control Element (MAC CE) including the identification information to the communication terminal.

4. The communication unit The base station according to claim 1 , wherein the base station transmits an RRC (Radio Resource Control) message including the plurality of DRX parameter sets to the communication terminal.

5. The communication unit The base station according to claim 4 , wherein the base station transmits the DRX parameter set and identification information associated with the DRX parameter set to the communication terminal.

6. 4. The base station according to claim 1, further comprising: a control unit that controls discontinuous reception in the communication terminal based on the first DRX parameter set after receiving a response message to the notification message from the communication terminal.

7. The control unit 7. The base station according to claim 6, wherein, after a predetermined time slot has elapsed based on a time slot in which the response message was received, the base station controls discontinuous reception in the communication terminal based on the first DRX parameter set.

8. The control unit The base station according to claim 6 , wherein the base station switches the DRX parameter set to be applied to the communication terminal based on a service usage status or a communication status of the communication terminal.

9. a communication unit that receives, from a base station, a notification message including information indicating a first DRX parameter set to be applied among a plurality of DRX parameter sets used for controlling discontinuous reception; a control unit that performs discontinuous reception in accordance with the first DRX parameter set.

10. Manage a plurality of DRX parameter sets used to control discontinuous reception in the communication terminal; A communication method executed in a base station, comprising transmitting, to the communication terminal, a notification message including information indicating a first DRX parameter set to be applied to the communication terminal from among the plurality of DRX parameter sets.

11. receiving, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception; A control method executed in a communication terminal, which performs discontinuous reception in accordance with the first DRX parameter set.

12. Manage a plurality of DRX parameter sets used to control discontinuous reception in the communication terminal; A program that causes a computer to execute the following: transmitting, to the communication terminal, a notification message including information indicating a first DRX parameter set to be applied to the communication terminal, out of the plurality of DRX parameter sets.

13. receiving, from a base station, a notification message including information indicating a first DRX parameter set to be applied from among a plurality of DRX parameter sets used for controlling discontinuous reception; A program that causes a computer to execute the following: performing discontinuous reception in accordance with the first DRX parameter set.

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