Communication device, base station, and communication method

Abstract

A communication device (100) is provided with: a receiving unit (110) which receives, from a base station (200), a radio resource control (RRC) message including first information for setting a plurality of search space set groups, and second information for setting a timer value for monitoring a physical downlink control channel (PDCCH), and which receives, from the base station (200), downlink control information (DCI) including an information field related to the monitoring of the PDCCH; and a control unit (120) which, on the basis of a value set in the information field, controls the start of monitoring of the PDCCH in accordance with one search space set group among the plurality of search space set groups. As the timer value, one value with respect to the plurality of search space sets is set.

Description

Cross - reference to related applications

[0001] This application is based on and claims the benefit of priority of patent application No. 2021 - 079352 filed on May 7, 2021, and all of the contents of that patent application are incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to a communication device, a base station, and a communication method used in a mobile communication system.

Background Art

[0003] In recent years, in 3GPP (registered trademark; the same shall apply hereinafter) (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, it has been considered to introduce power - saving technologies for reducing the power consumption of communication devices in the Radio Resource Control (RRC) connected state into the 5th - generation (5G) system (see, for example, Non - Patent Document 1).

[0004] For example, in order to reduce the power consumption required for monitoring the Physical Downlink Control Channel (PDCCH) in a communication device, it has been considered to increase the period of the search space corresponding to the candidate timing where the PDCCH is provided or to switch to a state where monitoring of the PDCCH in the search space is skipped (hereinafter, appropriately referred to as the "power - saving state").

[0005] In particular, by dynamically switching to the power - saving state during the active time in Discontinuous Reception (DRX) in the Radio Resource Control (RRC) connected state, an effect of reducing power consumption greater than that achieved by DRX - based power reduction can be obtained.

Prior Art Documents

Non - Patent Documents

[0006]

Non - Patent Document 1

Summary of the Invention

[0007] A communication device according to a first aspect includes a receiving unit (110) that receives a radio resource control (RRC) message including first information for setting a plurality of search space set groups and second information for setting a timer value for monitoring a physical downlink control channel (PDCCH) from a base station (200), and receives downlink control information (DCI) including an information field related to the monitoring of the PDCCH from the base station (200), and a control unit (120) that controls the start of the monitoring of the PDCCH according to one of the plurality of search space set groups based on a value set in the information field. As the timer value, one value for the plurality of search space sets is set.

[0008] A base station according to a second aspect includes a transmitting unit that transmits a radio resource control (RRC) message including first information for setting a plurality of search space set groups and second information for setting a timer value for monitoring a physical downlink control channel (PDCCH) to a communication device (100), and transmits downlink control information (DCI) including an information field related to the monitoring of the PDCCH to the communication device (100). As the timer value, one value for the plurality of search space sets is set.

[0009] The communication method according to the third aspect is a communication method used in a communication device (100), and includes a step of receiving, from a base station (200), a radio resource control (RRC) message including first information for setting a plurality of search space set groups and second information for setting a timer value for monitoring a physical downlink control channel (PDCCH); a step of receiving, from the base station (200), downlink control information (DCI) including an information field related to the monitoring of the PDCCH; and a step of controlling the start of the monitoring of the PDCCH according to one of the plurality of search space set groups based on a value set in the information field. The timer value is set for each of one or more downlink bandwidth parts (DL BWPs) set in the communication device (100).

[0010] The communication method according to the fourth aspect is a communication method used in a base station (200), and includes a step of transmitting, to a communication device (100), a radio resource control (RRC) message including first information for setting a plurality of search space set groups and second information for setting a timer value for monitoring a physical downlink control channel (PDCCH); and a step of transmitting, to the communication device (100), downlink control information (DCI) including an information field related to the monitoring of the PDCCH. As the timer value, one value for the plurality of search space sets is set.

Brief Description of the Drawings

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BEST MODE FOR CARRYING OUT THE INVENTION

[0012] It is considered that flexible power saving can be achieved by setting a plurality of search space sets with different search space periods and various search space sets such as a search space set that does not monitor the PDCCH in a communication device, and instructing the switching of the search space set by downlink control information (DCI).

[0013] Therefore, one of the objectives of the present disclosure is to provide a communication device, a base station, and a communication method that can achieve flexible power saving using various search space sets.

[0014] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0015] (System Configuration) First, with reference to FIG. 1, the configuration of the mobile communication system 1 according to the present embodiment will be described. The mobile communication system 1 is a system compliant with, for example, the technical specifications (Technical Specification: TS) of 3GPP. Hereinafter, as the mobile communication system 1, a 5th generation system (5th Generation System: 5GS) of the 3GPP standard, that is, a mobile communication system based on NR (New Radio) will be described as an example.

[0016] The mobile communication system 1 includes a network 10 and a user equipment (UE) 100 that communicates with the network 10. The network 10 includes an NG-RAN (Next Generation Radio Access Network) 20 that is a 5G radio access network and a 5GC (5G Core Network) 30 that is a 5G core network.

[0017] UE100 is a device used by a user. UE100 is a movable device such as, for example, 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 thereon. UE100 may be a transport aircraft other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided thereon. UE100 may be a sensor or a device provided thereon. Note that UE100 may be called by another name such as 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.

[0018] NG-RAN20 includes a plurality of base stations 200. Each base station 200 manages at least one cell. A cell constitutes the minimum unit of a communication area. One cell belongs to one frequency (carrier frequency) and is composed of one component carrier. The term "cell" may represent a radio communication resource or may represent a communication target of UE100. Each base station 200 can perform radio communication with UE100 present in its cell. The base station 200 communicates with UE100 using the protocol stack of the RAN. The base station 200 provides NR user plane and control plane protocol termination towards UE100 and is connected to 5GC30 via the NG interface. Such an NR base station 200 may be referred to as a gNodeB (gNB).

[0019] 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 performs mobility management of UE100. The UPF provides a function specialized for user plane processing. The AMF and the UPF are connected to the base station 200 via the NG interface.

[0020] Next, with reference to FIG. 2, a configuration example of the protocol stack according to this embodiment will be described.

[0021] The protocol for the radio section between UE 100 and base station 200 has a Physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an RRC layer.

[0022] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Between the PHY layer of UE 100 and the PHY layer of base station 200, data and control information are transmitted via a physical channel.

[0023] The MAC layer performs priority control of data, retransmission processing by Hybrid Automatic Repeat Request (HARQ), and a random access procedure, etc. Between the MAC layer of UE 100 and the MAC layer of base station 200, data and control information are transmitted via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and the allocated resources to UE 100.

[0024] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the PHY layer. Between the RLC layer of UE 100 and the RLC layer of base station 200, data and control information are transmitted via a logical channel.

[0025] The PDCP layer performs header compression / decompression and encryption / decryption.

[0026] An SDAP (Service Data Adaptation Protocol) layer may be provided as the upper layer of the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer performs mapping between an IP flow, which is a unit for the core network to perform QoS control, and a radio bearer, which is a unit for the AS (Access Stratum) to perform QoS control.

[0027] The RRC layer controls the logical channel, transport channel, and physical channel in response to the establishment, re - establishment, and release of a radio bearer. Between the RRC layer of the UE100 and the RRC layer of the base station 200, RRC signaling for various settings is transmitted. When there is an RRC connection between the RRC of the UE100 and the RRC of the base station 200, the UE100 is in the RRC connected state. When there is no RRC connection between the RRC of the UE100 and the RRC of the base station 200, the UE100 is in the RRC idle state. When the RRC connection between the RRC of the UE100 and the RRC of the base station 200 is suspended, the UE100 is in the RRC inactive state.

[0028] The NAS layer located above the RRC layer manages the session and mobility of the UE100. Between the NAS layer of the UE100 and the NAS layer of the core network device 300 (AMF), NAS signaling is transmitted. Note that the UE100 has an application layer etc. in addition to the protocol of the radio interface.

[0029] (Overview of Radio Communication Operation) Next, with reference to FIG. 3, an overview of the radio communication operation according to the present embodiment will be described. In the present embodiment, the search space may be referred to as a search space set.

[0030] The base station 200 sets a search space corresponding to a candidate timing where the PDCCH is provided for the UE 100. The UE 100 in the RRC connected state monitors the PDCCH in the set search space, receives downlink control information (DCI) carried by the PDCCH, and performs reception of the physical downlink shared channel (PDSCH) and / or transmission of the physical uplink shared channel (PUSCH) according to the resource allocation (scheduling) indicated by the DCI. For example, the UE 100 may monitor a set of PDCCH candidates according to the corresponding search space. That is, the UE 100 may monitor a set of PDCCH candidates in a control resource set (CORESET) in a downlink BWP (DL BWP: Downlink Bandwidth Part) of the serving cell where the PDCCH monitoring is set according to the corresponding search space. Here, "monitor" may indicate decoding each of the PDCCH candidates according to the DCI format to be monitored.

[0031] As shown in FIG. 3, in step S1, the base station 200 transmits an RRC message including setting information regarding the PDCCH (PDCCH setting information) to the UE 100, and performs various settings regarding the PDCCH on the UE 100. This RRC message is an RRC message specific to the UE, and may be, for example, an RRC Reconfiguration message. Here, the search space setting in the PDCCH setting includes a search space period (also referred to as a PDCCH monitoring period), a search space offset (also referred to as a PDCCH monitoring offset), a search space duration (e.g., the number of consecutive slots), symbols for PDCCH monitoring, an aggregation level, a type of search space, and a DCI format, etc. Here, each of the search spaces (each of the search space settings) may be associated with one CORESET. Also, the search space setting may be set for each of one or more DL BWPs. Here, the type of search space may include a UE-specific search space (USS: UE-specific Search Space) and / or a common search space for UEs (CSS: Common Search Space).

[0032] The DCI format includes a scheduling DCI format used for scheduling the PDSCH or PUSCH, and a non-scheduling DCI format not used for such scheduling. The DCI transmitted in the scheduling DCI format is called scheduling DCI, and the DCI transmitted in the non-scheduling DCI format is called non-scheduling DCI.

[0033] The scheduling DCI format includes a downlink DCI format (e.g., DCI format 1_0, DCI format 1_1, DCI format 1_2) used for scheduling the PDSCH and an uplink DCI format (e.g., DCI format 0_0, DCI format 0_1, DCI format 0_2) used for PUSCH scheduling. The scheduling DCI may be UE-specific DCI transmitted for each UE. For example, the scheduling DCI may be transmitted by applying an RNTI assigned to each UE.

[0034] On the other hand, the non-scheduling DCI format includes, for example, DCI format 2_0 and DCI format 2_6. The non-scheduling DCI may be DCI that can be transmitted to a plurality of UEs 100 simultaneously. For example, the non-scheduling DCI may be transmitted by applying a common RNTI to a plurality of UEs 100.

[0035] In step S2, UE 100 starts monitoring the PDCCH in the search space configured by base station 200. For example, each of DCI format 1_0, DCI format 0_0, DCI format 1_1, DCI format 0_1, DCI format 1_2, and DCI format 0_2 is configured for UE 100, and UE 100 monitors the PDCCH (DCI) based on the configuration. For example, base station 200 may configure UE 100 to monitor DCI format 1_0 and DCI format 0_0 in a certain search space. Also, base station 200 may configure UE 100 to monitor DCI format 1_1 and DCI format 0_1 in a certain search space. Also, base station 200 may configure UE 100 to monitor DCI format 1_2 and DCI format 0_2 in a certain search space. That is, for example, when base station 200 configures CSS for a certain search space, it may configure UE 100 to monitor the PDCCH candidates for DCI format 1_0 and DCI format 0_0. Also, when base station 200 configures CSS for a certain search space, it may configure UE 100 to monitor the PDCCH candidates for DCI format 2_0. Also, when base station 200 configures USS for a certain search space, it may configure UE 100 to monitor the PDCCH candidates for DCI format 1_0 and DCI format 0_0, or DCI format 1_1 and DCI format 0_1. Also, when base station 200 configures USS for a certain search space, it may configure UE 100 to monitor the PDCCH candidates for DCI format 1_0 and DCI format 0_0, or DCI format 1_2 and DCI format 0_2.

[0036] In step S3, UE 100 receives and detects DCI addressed to itself from base station 200. For example, UE 100 performs blind decoding of PDCCH using a C-RNTI (Cell-Radio Network Temporary Identifier), MCS-C-RNTI (Modulation and Coding Scheme-C-RNTI), or CS-RNTI (Configured Scheduling-RNTI) assigned to UE 100 from base station 200, and acquires the DCI that has been successfully decoded as the DCI addressed to itself. Here, the DCI transmitted from base station 200 has CRC parity bits scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI added thereto.

[0037] When the DCI indicates scheduling of PDSCH, in step S4, UE 100 receives downlink data from base station 200 using the scheduled PDSCH.

[0038] When the DCI indicates scheduling of PUSCH, in step S5, UE 100 transmits uplink data to base station 200 using the scheduled PUSCH.

[0039] (Overview of power saving technology) Next, with reference to FIG. 4, an overview of PDCCH skipping according to this embodiment will be described. Hereinafter, it is assumed that UE 100 is in the RRC connected state.

[0040] First, UE 100 monitors PDCCH provided at a predetermined period in the search space based on the search space configuration set by base station 200. Such a PDCCH monitoring state is an example of the first state.

[0041] Second, the base station 200 transmits a skip indication DCI that instructs PDCCH skipping to the UE 100. The skip indication DCI is an example of a switching indication DCI. The skip indication DCI is either a scheduling DCI or a non-scheduling DCI. In this embodiment, it is mainly assumed that the scheduling DCI is used as the skip indication DCI.

[0042] Third, in response to receiving the skip indication DCI from the base station 200, the UE 100 skips monitoring the PDCCH for a predetermined period. Such a PDCCH skipping state is an example of the second state (power saving state). The predetermined period for skipping the PDCCH monitoring may be set by upper layer signaling (RRC message). The predetermined period may be determined by a timer value (i.e., the set value of the switching timer), or may be determined by the number of consecutive slots or the number of consecutive search spaces.

[0043] By such PDCCH skipping, the power consumption required for the UE 100 to monitor the PDCCH is reduced, and dynamic power saving can be realized.

[0044] Next, with reference to FIG. 5, an overview of the search space set switching according to this embodiment will be described.

[0045] First, the base station 200 sets a plurality of search space sets, which are sets of settings related to the search space, to the UE 100 by means of upper layer signaling (RRC message). Such a set of settings related to the search space is referred to as a search space set (SSS) or a search space set group (SSSG), but hereinafter, it will mainly be referred to as SSSG. One SSSG includes one or more search space settings and is identified by the index of the SSSG. Here, the base station 200 sets to the UE 100 an SSSG #0 (first search space set) in which a search space is provided at a predetermined period and an SSSG #1 (second search space set) in which a search space is provided at a period longer than the predetermined period. Here, an example is shown in which the base station 200 sets two SSSGs, SSSG #0 and SSSG #1, to the UE 100, but three or more SSSGs may be set to the UE 100 for each of one or more BWPs (for example, DL BWP). Note that setting a plurality of BWPs (or three or more SSSGs) to the UE 100 may mean setting a plurality of SSSGs (or three or more SSSGs) for one BWP, or may mean setting a plurality of SSSGs (or three or more SSSGs) for a plurality of BWPs.

[0046] Second, the UE 100 monitors, in the search space, a PDCCH provided at a predetermined period based on the SSSG #0. The state in which such an SSSG #0 is applied is an example of the first state.

[0047] Third, the base station 200 transmits to the UE 100 a switching instruction DCI for instructing SSSG switching. Switching The instruction DCI is a scheduling DCI or a non-scheduling DCI, but in this embodiment, it is mainly assumed that the scheduling DCI is used as the switching instruction DCI. That is, the base station 200 uses the scheduling DCI to instruct the UE 100 to switch from the SSSG #0 to the SSSG #1.

[0048] Fourth, UE 100 starts switching to SSSG#1 in response to receiving the switching indication DCI. UE 100 performs the switching to SSSG#1 at a symbol that is the switching delay after the last symbol of the PDCCH in SSSG#0. Such a switching delay is set from base station 200 to UE 100 by upper layer signaling (RRC message).

[0049] Fifth, UE 100 monitors, in the search space, a PDCCH provided at a period longer than a predetermined period based on SSSG#1. A state where such SSSG#1 is applied is an example of the second state (power saving state).

[0050] By such a search space set switching, the power consumption required for UE 100 to monitor the PDCCH is reduced, and dynamic power saving can be realized.

[0051] Note that the base station 200 may also instruct the switching from SSSG#1 to SSSG#0 by means of DCI, similar to the switching from SSSG#0 to SSSG#1, or the UE 100 may switch from SSSG#1 to SSSG#0 using a timer. The timer value of such a switching timer is set by the base station 200 to the UE 100 by means of upper layer signaling (RRC message). The UE 100 starts monitoring the PDCCH in SSSG#1 in response to the detection of the switching instruction DCI to SSSG#1, and sets the value of the switching timer to the value set by the upper layer to start the switching timer. The UE 100 decrements the value of the switching timer, stops monitoring the PDCCH in SSSG#1 when the switching timer expires, and starts monitoring the PDCCH in SSSG#0 after the switching delay. Here, "#0" in SSSG#0 and "#1" in SSSG#1 indicate indexes (also referred to as search space group IDs) for the set (group) of search spaces. That is, one or more search space sets may be associated with the set (group) of search spaces identified by the index. For example, the base station 200 may set a set (group) of search spaces for the UE 100 by setting an index related to the one or more search space sets. Here, in this embodiment, the name SSSG is merely an example, and any name may be used as long as it is a set (group) of search spaces associated with one or more search space sets.

[0052] In the search space set switching, by setting the UE100 not to have a search space in one SSSG to be set, and indicating the switching to the one SSSG by DCI, the same operation as the above-mentioned PDCCH skipping can be realized. Also, in other SSSGs to be set for the UE100, a setting with a long search space period can be made, and the switching to the one SSSG can also be indicated by DCI. In order to realize such an operation, it is necessary to set a total of three SSSGs for the UE100, namely, an SSSG with a normal search space period, an SSSG without a search space, and an SSSG with a long search space period. Also, when further setting an SSSG with an even longer search space period for the UE100, it is necessary to set a total of four SSSGs for the UE100. By setting such various SSSGs for the UE100 and indicating the switching of the SSSGs by DCI, flexible power saving can be realized.

[0053] Next, with reference to FIG. 6, the DRX and power saving states according to this embodiment will be described.

[0054] When DRX is set for the UE100, the UE100 discontinuously monitors the PDCCH using the DRX operation. Specifically, the DRX operation is controlled by the following DRX parameters. · DRX cycle: Defines the period in which the UE100 wakes up. · On-duration: The period during which the UE100 waits to receive the PDCCH after waking up. When the UE100 successfully decodes the PDCCH, the UE100 maintains the wake-up state and starts an inactivity-timer. · Inactivity-timer: The time period that the UE100 waits from the last successful PDCCH decoding, and defines the period during which the UE100 goes back to sleep when the PDCCH decoding fails. · Retransmission timer: Defines the time period during which retransmission is expected.

[0055] In this way, since the UE 100 with DRX configured does not need to monitor the PDCCH in the sleep state (i.e., the reception off period), the power consumption of the UE 100 can be reduced. On the other hand, while the UE 100 is in the active time, it waits to receive the PDCCH and monitors the PDCCH in the search space. The active time is the time when any one of the on-duration timer (drx-onDurationTimer), inactivity timer (drx-InactivityTimer), downlink retransmission timer (drx-RetransmissionTimerDL), and uplink retransmission timer (drx-RetransmissionTimerUL) is operating. The downlink retransmission timer (drx-RetransmissionTimerDL) and the uplink retransmission timer (drx-RetransmissionTimerUL) are examples of retransmission-related timers for DRX operation in the RRC connected state.

[0056] By performing the above-mentioned PDCCH skipping or search space set switching within the active time of DRX, it is possible to dynamically switch to the power saving state within the active time, and an effect of reducing power consumption greater than that of power saving by DRX can be obtained.

[0057] Here, when using the scheduling DCI as the switching instruction DCI for instructing the switching to the power saving state, data transmission and reception occur between the base station 200 and the UE 100, and data retransmission processing by HARQ may be required. Therefore, if the UE 100 immediately starts switching to the power saving state in response to the reception of the scheduling DCI instructing the switching to the power saving state, there is a concern that the HARQ processing cannot be appropriately performed.

[0058] Also, the UE 100 in the RRC connected state performs sounding reference signal (SRS) transmission to the base station 200, channel state information (CSI) measurement, and CSI reporting to the base station 200. Since the period during which the UE 100 is in the power saving state is considered to be a period during which data transmission and reception are not temporarily performed, it is desirable to be able to reduce the power consumption required for SRS transmission, CSI measurement, and CSI reporting.

[0059] (Configuration of User Equipment) Next, with reference to FIG. 7, the configuration of the UE 100 according to the present embodiment will be described. The UE 100 includes a communication unit 110 and a control unit 120.

[0060] The communication unit 110 performs wireless communication with the base station 200 by transmitting and receiving wireless signals to and from the base station 200. The communication unit 110 has at least one receiver and at least one transmitter. The receiver and the transmitter may be configured to include an antenna and an RF circuit. The antenna converts a signal into a radio wave and radiates the radio wave into space. Also, the antenna receives a radio wave in space and converts the radio wave into a signal. The RF circuit performs analog processing of signals transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, and the like.

[0061] The control unit 120 performs various controls in the UE 100. The control unit 120 controls the 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 a program and a memory for storing the program. The processor may execute the program to perform the operations of the control unit 120. The control unit 120 may also 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 the processing of the RAN protocol stack. Note that the memory stores the program executed by the processor, the parameters related to the program, and the data related to the program. 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 part of the memory may be included in the processor.

[0062] In the UE100 according to this embodiment, in the first state where the communication unit 110 monitors the PDCCH in the search space, the communication unit 110 receives, on the PDCCH from the base station 200, scheduling DCI indicating radio resources (specifically, PDSCH resources and PUSCH resources) allocated to the UE100. The control unit 120 controls the communication unit 110 to receive or transmit data using the radio resources based on the scheduling DCI. When the communication unit 110 receives scheduling DCI instructing a switch to a second state (for example, a power saving state) in which the setting related to the search space is different from the first state, the control unit 120 suspends the start of the switch while the retransmission-related timer associated with the HARQ process for the data is operating. Thereby, even when scheduling DCI is used as an instruction to switch to the power saving state, it becomes possible to appropriately perform the HARQ process. In the first operation example described later, the details of such an operation will be described.

[0063] In the UE100 according to this embodiment, in the first state where the control unit 120 monitors the PDCCH in the search space, the control unit 120 performs predetermined control for controlling at least one of the operations of SRS transmission to the base station 200, CSI measurement, and CSI report to the base station 200. The communication unit 110 receives, on the PDCCH from the base station 200, switching instruction DCI instructing a switch to a second state (for example, a power saving state) in which the setting related to the search space is different from the first state. In response to the reception of the switching instruction DCI, the control unit 120 performs control different from the predetermined control for at least one of the operations of SRS transmission, CSI measurement, and CSI report. Thereby, in SRS transmission, CSI measurement, and CSI report, control optimized for the power saving state can be applied. Therefore, while reducing the power consumption required for monitoring the PDCCH, further power consumption reduction can be realized. In the second operation example described later, the details of such an operation will be described.

[0064] Note that the first state may be a state in which the first SSSG among a plurality of SSSGs set for the UE 100 by the base station 200 is applied. The second state may be a state in which a second SSSG different from the first SSSG among the plurality of SSSGs is applied. The communication unit 110 may receive, as a switching instruction, scheduling DCI instructing switching from the first SSSG to the second SSSG. Also, the first state may be a state of monitoring a PDCCH provided at a predetermined period in a search space. The second state may be a state of monitoring a PDCCH in a search space provided at a period longer than the predetermined period, or a state of skipping monitoring of the PDCCH. The second state may be realized by the second SSSG described above.

[0065] In the UE 100 according to the present embodiment, the communication unit 110 receives, from the base station 200, correspondence relationship information indicating a correspondence relationship between each index of one or more SSSGs set for the UE 100 and a value set in an information field in switching instruction DCI instructing switching of the SSSG applied by the UE 100. The one or more SSSGs include at least one of an SSSG that periodically monitors a PDCCH and an SSSG that skips monitoring of the PDCCH. When the communication unit 110 receives switching instruction DCI on the PDCCH, the control unit 120 controls monitoring of the PDCCH using an SSSG having an index corresponding to the value set in the information field in the received switching instruction DCI based on the correspondence relationship information. Thereby, flexible power saving can be realized using various search space sets. Also, since one information field provided in the switching instruction DCI can specify any one of a plurality of search space sets having different search space periods, or a search space set that does not perform monitoring of the PDCCH, an increase in the size of the DCI can be suppressed even when using various search space sets. In the third operation example described later, details of such an operation will be described.

[0066] In the UE 100 according to this embodiment, the communication unit 110 receives a switching instruction DCI from the base station 200 that instructs switching to one of three or more SSSGs set in the UE 100. Based on the reception of the switching instruction DCI, the control unit 120 may start a timer that determines the duration for which monitoring of the PDCCH in the one SSSG or skipping of the PDCCH monitoring is applied. When the timer expires, the UE 100 (control unit 120) switches to the default SSSG set by the base station 200 among the three or more SSSGs. This enables flexible power saving using various search space sets. Specifically, even when the UE 100 performs switching of the SSSG based on a timer and three or more SSSGs are set in the UE 100, the base station 200 can grasp the SSSG to be switched to. It becomes possible to perform switching based on a timer for various SSSGs. In the fourth operation example described later, the details of such an operation will be described.

[0067] (Configuration of the base station) Next, with reference to FIG. 8, the configuration of the base station 200 according to this embodiment will be described. The base station 200 includes a communication unit 210, a network interface 220, and a control unit 230.

[0068] The communication unit 210 receives, for example, a radio signal from the UE 100 and transmits a radio signal to the UE 100. The communication unit 210 may include one or more receivers that receive radio signals and one or more transmitters that transmit radio signals.

[0069] The network interface 220 transmits and receives signals to and from the network. The network interface 220 receives, for example, a signal from an adjacent base station connected via an Xn interface, which is a base station - to - base station interface, and transmits a signal to the adjacent base station. Also, the network interface 220 receives, for example, a signal from a core network device 300 connected via an NG interface and transmits a signal to the core network device 300.

[0070] The control unit 230 performs various controls in the base station 200. For example, the control unit 230 controls communication with the UE 100 via the communication unit 210. Also, for example, the control unit 230 controls communication with nodes (e.g., adjacent base stations, core network devices 300) via the network interface 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 for storing the program. The processor may execute the 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 an antenna and an RF circuit. The digital processing includes processing of the RAN protocol stack. Note that the memory stores a program executed by the processor, parameters related to the program, and data related to the program. All or part of the memory may be included in the processor.

[0071] The base station 200 according to the present embodiment performs wireless communication with the UE 100 that monitors the PDCCH in the search space. The communication unit 210 transmits to the UE 100 correspondence information indicating the correspondence between each index of one or more SSSGs set for the UE 100 and a value set in an information field in switching instruction DCI that instructs switching of the SSSG applied in the UE 100. The one or more SSSGs include at least one of an SSSG that periodically monitors the PDCCH and an SSSG that skips monitoring of the PDCCH.

[0072] In the base station 200 according to the present embodiment, the communication unit 210 transmits to the UE 100 switching instruction DCI that instructs switching to one of three or more SSSGs set for the UE 100. The control unit 230 may set for the UE 100 a default SSSG that becomes the switching destination when a timer that determines the duration for which monitoring of the PDCCH or skipping of monitoring of the PDCCH in the one SSSG is applied expires.

[0073] (First operation example) Next, with reference to FIG. 9, the first operation example according to the present embodiment will be described.

[0074] As described above, when using scheduling DCI as the switching instruction DCI, HARQ processing, which is data retransmission processing by HARQ, may be required. Therefore, if UE 100 immediately starts switching to the power saving state, there is a concern that HARQ processing cannot be appropriately performed. Thus, UE 100 (control unit 120) holds the start of the switching instructed by the switching instruction DCI while the retransmission-related timer associated with the HARQ processing for the data scheduled by the switching instruction DCI (scheduling DCI) is operating.

[0075] As shown in FIG. 9, in step S11, UE 100 (communication unit 110) receives, on the PDCCH from base station 200, scheduling DCI as the switching instruction DCI. Such scheduling DCI may include an information field indicating the target SSSG in addition to the information field indicating the PDSCH resource or PUSCH resource allocated to UE 100.

[0076] In step S12, UE100 (communication unit 110) receives or transmits data scheduled by scheduling DCI. For example, UE100 (communication unit 110) receives downlink data using the allocated PDSCH resource or transmits uplink data using the allocated PUSCH resource. When UE100 (communication unit 110) receives downlink data, UE100 (control unit 120) attempts to decode the received downlink data and feeds back to base station 200 a HARQ feedback indicating whether the data decoding was successful, that is, ACK or NACK. When UE100 (communication unit 110) transmits uplink data, UE100 (control unit 120) receives from base station 200 a HARQ feedback indicating whether the base station 200 successfully decoded the uplink data, that is, ACK or NACK. UE100 (control unit 120) manages HARQ processing for each piece of data received or transmitted by a timer and continues the HARQ processing until the data decoding of the data is completed.

[0077] In step S13, UE100 (control unit 120) determines whether any of the next retransmission-related timers used for HARQ processing is operating.

[0078] · Downlink HARQ RTT timer (drx-HARQ-RTT-TimerDL) A timer used for HARQ processing of downlink data, which defines the minimum period until a downlink allocation for HARQ retransmission expected by the MAC entity of UE100. UE100 (control unit 120) starts the downlink HARQ RTT timer in response to the transmission of HARQ feedback for downlink data. While the downlink HARQ RTT timer is operating, UE100 (control unit 120) does not need to monitor the PDCCH.

[0079] · Downlink retransmission timer (drx-RetransmissionTimerDL) A timer used for HARQ processing of downlink data, which defines the maximum period until receiving a downlink retransmission. When the downlink HARQ RTT timer expires, if the UE100 (control unit 120) fails to successfully decode the downlink data, it starts the downlink retransmission timer. During the operation of the downlink retransmission timer, the UE100 (control unit 120) monitors the PDCCH and waits for the retransmitted data.

[0080] · Uplink HARQ RTT timer (drx-HARQ-RTT-TimerUL) A timer used for HARQ processing of uplink data, which defines the minimum period until the MAC entity of the UE100 receives a HARQ retransmission grant. When the UE100 (control unit 120) transmits uplink data, it starts the downlink retransmission timer. During the operation of the uplink HARQ RTT timer, the UE100 (control unit 120) does not need to monitor the PDCCH.

[0081] · Uplink retransmission timer (drx-RetransmissionTimerUL) A timer used for HARQ processing of uplink data, which defines the maximum period until receiving an uplink retransmission grant. When the uplink HARQ RTT timer expires, the UE100 (control unit 120) starts the uplink retransmission timer. During the operation of the uplink retransmission timer, the UE100 (control unit 120) monitors the PDCCH.

[0082] When any of these retransmission-related timers is in operation (step S13: YES), in step S14, the UE100 (control unit 120) holds off starting the handover indicated by the handover instruction DCI received in step S11.

[0083] On the other hand, when none of the retransmission-related timers is operating (step S13: NO), in step S15, the UE 100 (control unit 120) starts or executes the handover instructed by the handover instruction DCI received in step S11. For example, the UE 100 (control unit 120) may execute the SSSG handover from the first slot after the retransmission-related timer expires.

[0084] Thus, in the first operation example, the period during which the retransmission-related timer is operating constitutes at least a part of the handover delay time (Switch delay) of the handover instructed by the handover instruction DCI. When the handover delay time is set by upper layer signaling (RRC message), the UE 100 (control unit 120) may hold off starting the handover instructed by the handover instruction DCI even after the handover delay time set by the upper layer signaling has elapsed, during the period when the retransmission-related timer is operating.

[0085] Also, the handover delay time may include the following periods during which the retransmission-related timer is operating. · The period during which the drx-HARQ-RTT-TimerDL started for the corresponding HARQ process at the first symbol after the end of transmission of the DL HARQ feedback is operating: · The period during which the drx-RetransmissionTimerDL started when the corresponding HARQ process at the first symbol after the expiration of the drx-HARQ-RTT-TimerDL is not successfully decoded is operating: · The period during which the drx-HARQ-RTT-TimerUL started for the corresponding HARQ process at the first symbol after the end of the first transmission (within the bundle) of the corresponding PUSCH is operating: · The period during which the drx-RetransmissionTimerUL started for the corresponding HARQ process at the first symbol after the expiration of the drx-HARQ-RTT-TimerUL is operating.

[0086] Also, when the UE100 (control unit 120) is executing a plurality of HARQ processes, if at least one of the retransmission-related timers of the plurality of HARQ processes is operating, the start of the switching instructed by the switching instruction DCI may be postponed. For example, the UE100 may execute SSSG switching based on the expiration of the drx-RetransmissionTimerDL corresponding to all HARQ processes and / or the expiration of the drx-RetransmissionTimerUL corresponding to all HARQ processes (e.g., from the first slot after expiration).

[0087] Note that the UE100 (control unit 120) may perform the above operations when receiving a configured DL assignment (i.e., a downlink DCI format having a CRC scrambled with a CS-RNTI) and / or a configured UL grant (i.e., an uplink DCI format having a CRC scrambled with a CS-RNTI).

[0088] In addition, in the first operation example, various timers for existing DRX are used. However, the present invention is not limited to this, and timers used for HARQ processing and retransmission processing of PDCCH skipping and / or SSSG switching set in the upper layer may also be used. Such timers include, for example, DCIbasedPowerSaving-HARQ-RTT-TimerDL, DCIbasedPowerSaving-HARQ-RTT-TimerUL, DCIbasedPowerSaving-RetransmissionTimerDL, DCIbasedPowerSaving-RetransmissionTimerUL, and the like. Here, DCIbasedPowerSaving-HARQ-RTT-TimerDL is an example of a downlink HARQ RTT timer, DCIbasedPowerSaving-HARQ-RTT-TimerUL is an example of an uplink HARQ RTT timer, DCIbasedPowerSaving-RetransmissionTimerDL is an example of a downlink retransmission timer, and DCIbasedPowerSaving-RetransmissionTimerUL is an example of an uplink retransmission timer.

[0089] Next, with reference to FIG. 10, the first operation example according to the present embodiment will be described focusing on the downlink.

[0090] In step S101, the UE 100 (communication unit 110) receives a downlink scheduling DCI as a switching instruction DCI on the PDCCH. The downlink scheduling DCI is a DCI that allocates radio resources (i.e., PDSCH resources) for downlink data. The UE 100 (communication unit 110) receives downlink data from the base station 200 using the PDSCH resources allocated by the downlink scheduling DCI. The UE 100 (control unit 120) attempts to decode the received downlink data.

[0091] In step S102, UE100 (communication unit 110) transmits HARQ feedback indicating whether it has successfully decoded the downlink data received in step S102 to base station 200.

[0092] In step S103, UE100 (control unit 120) starts a downlink HARQ RTT timer in response to the transmission of HARQ feedback corresponding to the downlink data. During the operation of the downlink HARQ RTT timer, UE100 (control unit 120) holds off on starting the handover indicated by the handover indication DCI.

[0093] When the downlink HARQ RTT timer expires (step S104: YES), in step S105, UE100 (control unit 120) determines whether it has successfully decoded the downlink data. If it has successfully decoded the downlink data (step S105: YES), in step S106, UE100 (control unit 120) starts the handover indicated by the handover indication DCI.

[0094] On the other hand, if it has not successfully decoded the downlink data (step S105: NO), in step S107, UE100 (control unit 120) starts a downlink retransmission timer in response to the expiration of the downlink HARQ RTT timer. During the operation of the downlink retransmission timer, UE100 (control unit 120) monitors the PDCCH and holds off on starting the handover indicated by the handover indication DCI.

[0095] When the downlink retransmission timer expires (step S108: YES), in step S106, UE100 (control unit 120) starts the handover indicated by the handover indication DCI. If retransmitted data is received from base station 200 during the operation of the downlink retransmission timer, UE100 (control unit 120) may stop the downlink retransmission timer and return the process to step S102.

[0096] Next, with reference to FIG. 11, the first operation example according to the present embodiment will be described focusing on the uplink.

[0097] In step S201, the UE 100 (communication unit 110) receives an uplink scheduling DCI as a switching instruction DCI on the PDCCH. The uplink scheduling DCI is a DCI that allocates radio resources (i.e., PUSCH resources) for uplink data.

[0098] In step S202, the UE 100 (communication unit 110) transmits uplink data to the base station 200 using the PUSCH resources allocated by the uplink scheduling DCI.

[0099] In step S203, the UE 100 (control unit 120) starts an uplink HARQ RTT timer in response to the transmission of the uplink data. The UE 100 (control unit 120) holds the start of the switching instructed by the switching instruction DCI during the operation of the uplink HARQ RTT timer.

[0100] When the uplink HARQ RTT timer expires (step S204: YES), in step S205, the UE 100 (control unit 120) starts an uplink retransmission timer. The UE 100 (control unit 120) monitors the PDCCH during the operation of the uplink retransmission timer and holds the start of the switching instructed by the switching instruction DCI.

[0101] When the uplink retransmission timer expires (step S206: YES), in step S207, the UE 100 (control unit 120) starts the switching instructed by the switching instruction DCI.

[0102] Thus, according to the first operation example of the present embodiment, the UE 100 that has received the scheduling DCI as a switching instruction suspends the start of switching while the retransmission-related timer associated with the HARQ process for the data scheduled by the scheduling DCI is operating. Thereby, even when using the scheduling DCI as a switching instruction, it becomes possible to appropriately perform the HARQ process.

[0103] In addition, in the first operation example, consideration may be given to the CSI report to the base station 200. For example, when the UE 100 that has received the switching instruction DCI is instructed to perform an aperiodic CSI report to the base station 200 by the scheduling DCI, the UE 100 (control unit 120) transmits the CSI report to the base station 200 in the scheduled PUSCH, and may suspend the start of the switching instructed by the switching instruction DCI until this CSI report is performed. Then, the UE 100 (control unit 120) may start the switching instructed by the switching instruction DCI in response to transmitting the CSI report in the scheduled PUSCH. Details of the CSI report will be described in the second operation example described later.

[0104] (Second operation example) Next, with reference to FIG. 12, the second operation example according to the present embodiment will be described.

[0105] As described above, since the period during which the UE 100 is in the power saving state is considered to be a period during which data transmission and reception are not temporarily performed, it is desirable to also reduce the power consumption required for SRS transmission, CSI measurement, and CSI report.

[0106] Here, SRS transmission refers to the operation of transmitting SRS, which is an uplink physical signal for channel estimation used by base station 200 for estimating the uplink channel state, to base station 200. UE100 performs SRS transmission according to the settings from base station 200. SRS reporting is an operation for uplink link adaptation. Link adaptation is to adapt the modulation and coding scheme (MCS) applied to data transmission to the channel state. During the period when UE100 is in the power saving state, since there is little need to perform uplink link adaptation, SRS transmission is suppressed.

[0107] CSI measurement refers to the operation of measuring reference signals used for estimating the downlink channel state. UE100 performs CSI measurement according to the settings from base station 200. For example, UE100 performs CSI measurement based on at least one of the channel state information reference signal (CSI-RS) transmitted by base station 200 and the synchronization signal / physical broadcast channel (SS / PBCH) block. CSI reporting refers to the operation of transmitting a CSI report indicating the channel state estimated according to the result of CSI measurement to base station 200. UE100 performs CSI reporting according to the settings from base station 200. For example, the channel state includes one or more of the channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), SS / PBCH block resource indicator (SSBRI), CSI-RS resource indicator (CRI), layer indicator (LI), and Layer 1 reference signal received power (L1-RSRP). The CSI report may be performed on the PUCCH or PUSCH. CSI measurement and CSI reporting are operations for downlink link adaptation. During the period when UE100 is in the power saving state, since there is little need to perform downlink link adaptation, CSI measurement and CSI reporting are suppressed.

[0108] As shown in FIG. 12, in step S301, the UE 100 (control unit 120) performs predetermined control to control at least one of SRS transmission to the base station 200, CSI measurement, and CSI reporting to the base station 200 in the first state where it monitors the PDCCH in the search space. In the first state, the UE 100 (control unit 120) may perform at least one of SRS transmission, CSI measurement, and CSI reporting periodically. For example, in the first state, the UE 100 (control unit 120) performs at least one of periodic SRS transmission and periodic CSI reporting. The periodic SRS transmission may include semi-persistent SRS transmission. The periodic CSI reporting may include semi-persistent CSI reporting performed on the PUCCH or PUSCH.

[0109] In step S301, the UE 100 (communication unit 110) receives, on the PDCCH, a switching instruction DCI that instructs a switch to a second state (for example, a power saving state) in which the setting related to the search space is different from the first state. In the second operation example, the switching instruction DCI is not limited to the scheduling DCI as described above and may be non-scheduling DCI. The switching instruction DCI may include an information field indicating the target SSSG.

[0110] In step S303, the UE 100 (control unit 120) performs control different from the predetermined control for at least one of SRS transmission, CSI measurement, and CSI reporting in response to the reception of the switching instruction DCI.

[0111] For example, within the switching delay time from the first state to the second state, the UE 100 (control unit 120) stops at least one of SRS transmission, CSI measurement, and CSI reporting. The UE 100 (control unit 120) may stop periodic SRS transmission and periodic CSI reporting within the switching delay time. Such control is that "within the switching delay time composed of Pswitch symbols, the UE · Periodic SRS transmission and semi-persistent SRS transmission · Semi-persistent CSI configured for PUSCH · Periodic CSI reporting on PUCCH that is L1-RSRP when ps-TransmitPeriodicL1-RSRP is not configured with the value true · It may be expressed as "it is not expected to perform periodic CSI reporting that is not L1-RSRP on PUCCH when ps-TransmitOtherPeriodicCSI is not configured with the value true".

[0112] In the second operation example, the first state is a state of monitoring a PDCCH provided at a predetermined period in a search space, and the second state may be a state of skipping the monitoring of the PDCCH (PDCCH skipping state) (see FIG. 4). UE100 (control unit 120) may not perform at least one of SRS transmission, CSI measurement, and CSI reporting in the second state.

[0113] In the second operation example, the first state is a state of monitoring a PDCCH provided at a predetermined period in a search space, and the second state may be a state of monitoring the PDCCH in a search space provided at a period longer than the predetermined period (see FIG. 5). The switching from the first state to the second state may be realized by SSSG switching. UE100 (control unit 120) may perform at least one of SRS transmission, CSI measurement, and CSI reporting only in the time interval of the search space in the second state.

[0114] For example, UE100 (control unit 120) may perform non-periodic SRS transmission only in the monitoring slot which is the time interval of the search space in the second state. Such control may be expressed as "UEs in which SSSG switching is set by upper layer signaling do not expect SRS resources to be available outside the corresponding monitoring slot in order to trigger non-periodic SRS transmission when the period of the search space is longer than a predetermined value (for example, 80 milliseconds).".

[0115] Also, in the second state, the UE 100 (control unit 120) may perform CSI measurement only in a monitoring slot which is a time interval of the search space. Such control may be expressed as "for a UE in which SSSG switching is set by upper layer signaling, the most recent CSI measurement opportunity for CSI reporting excludes slots other than the monitoring slot corresponding to the search space", or may be expressed as "for a UE in which SSSG switching is set by upper layer signaling, when the period of the search space is longer than a predetermined value (e.g., 80 milliseconds), it is not expected that CSI-RS resources are available outside the corresponding monitoring slot".

[0116] Thus, according to the second operation example of the present embodiment, the UE 100 that has received the switching instruction DCI performs control different from the control before receiving the switching instruction DCI for at least one of SRS transmission, CSI measurement, and CSI reporting in response to the reception of the switching instruction DCI. Thereby, in SRS transmission, CSI measurement, and CSI reporting, control optimized for the power saving state, for example, control optimized for an extended search space period, can be applied, so that while reducing the power consumption required for monitoring the PDCCH, further power saving can be realized.

[0117] (Third operation example) Next, with reference to FIG. 13, a third operation example according to the present embodiment will be described.

[0118] In the third operation example, an operation of performing power saving by SSSG switching is assumed. Specifically, one or more SSSGs can be set for the UE 100 from various SSSGs including a plurality of SSSGs having different search space periods and an SSSG having no search space, and flexible power saving is realized by instructing the SSSG switching by DCI.

[0119] As shown in FIG. 13, in step S401, the base station 200 (communication unit 210) transmits one or more RRC messages to the UE 100. The one or more RRC messages may include dedicated RRC messages (e.g., RRCReconfiguration messages) transmitted individually to the UE. The UE 100 (communication unit 110) receives the RRC messages.

[0120] The RRC message includes correspondence information indicating the correspondence between each index of one or more SSSGs to be set for the UE 100 and the value set in an information field (hereinafter referred to as the “SSSG information field”) in the switching instruction DCI instructing the switching of the SSSG to be applied by the UE 100. The one or more SSSGs include at least one of an SSSG that periodically monitors the PDCCH and an SSSG that skips the monitoring of the PDCCH.

[0121] For example, when setting four SSSGs for the UE 100, the correspondence information includes information such as “SSSG index #0: value “00””, “SSSG index #1: value “01””, “SSSG index #2: value “10””, and “SSSG index #3: value “11””. The base station 200 is not limited to setting these four SSSGs for the UE 100 all at once. For example, the four SSSGs may be set for the UE 100 in two separate times, with two SSSGs each time. Note that the value set in the SSSG information field may be configured in a bitmap format. For example, as in “SSSG index #0: value “1000””, “SSSG index #1: value “0100””, “SSSG index #2: value “0010””, and “SSSG index #3: value “0001””, the position (code point) of the bit that is “1” may be associated with the SSSG index.

[0122] The RRC message further includes search space configuration information associated with each of the SSSG indices. The search space configuration information includes one or more search space configurations. Each search space configuration includes a search space period, a search space offset, a search space duration (e.g., the number of consecutive slots), symbols for PDCCH monitoring, an aggregation level, a type of search space, and a DCI format, etc.

[0123] For example, the search space configuration information associated with SSSG index #0 is information for setting a first search space period as the search space period. The search space configuration information associated with SSSG index #1 is information for setting a second search space period as the search space period. The search space configuration information associated with SSSG index #2 is information for setting a third search space period as the search space period. The search space configuration information associated with SSSG index #3 is information indicating that no search space is set. That is, SSSG index #3 is associated with search space configuration information indicating PDCCH skipping.

[0124] The RRC message may include field configuration information indicating the presence or absence of an SSSG information field for each one or more DCI formats. The switching indication DCI is a DCI having a DCI format in which the SSSG information field is indicated to be present by the field configuration information. For non-scheduling DCI and / or scheduling DCI, the presence or absence of the SSSG information field may be set either commonly or independently. The presence or absence of the SSSG information field may be set commonly for DCI format 1_1 and DCI format 0_1, and may be set commonly for DCI format 1_2 and DCI format 0_2.

[0125] The RRC message may include bit number setting information indicating the number of bits of the SSSG information field for one or more DCI formats. For non-scheduling DCI and / or scheduling DCI, the number of bits of the SSSG information field may be directly set either commonly or independently. The number of bits of the SSSG information field may be set commonly for DCI format 1_1 and DCI format 0_1, and / or commonly for DCI format 1_2 and DCI format 0_2. For example, an SSSG information field of up to 2 bits may be set for DCI format 1_1 and / or DCI format 0_1, and / or an SSSG information field of 1 bit may be set for DCI format 1_2 and DCI format 0_2.

[0126] The RRC message may include a timer setting value of a switching timer for one or more SSSGs. Details of such a switching timer will be described in the fourth operation example below.

[0127] In step S402, the UE 100 (control unit 120) stores the information set by the base station 200.

[0128] In step S403, the base station 200 (communication unit 210) may transmit to the UE 100 a MAC CE (hereinafter referred to as the "SSSG state selection MAC CE") that specifies activation or deactivation of the SSSG for each SSSG index. The UE 100 (communication unit 110) receives the SSSG state selection MAC CE. The SSSG state selection MAC CE indicates activation / deactivation for each SSSG index. The activated SSSG becomes valid as the target SSSG for switching, and the deactivated SSSG becomes invalid as the target SSSG for switching. However, deactivation of the default SSSG may be prohibited. The default SSSG will be described in the fourth operation example below.

[0129] For example, the SSSG state selection MAC CE is identified by a MAC sub-header having an LCID defined for the SSSG state selection MAC CE. The SSSG state selection MAC CE may include a "cell ID field" indicating the serving cell to which the SSSG state selection MAC CE is applied. The SSSG state selection MAC CE may include a "Ti field" indicating activation / deactivation for each entry "i" of the SSSG index list consisting of the SSSG index. The "Ti field" includes the "T0 field" to the "T(n-1) field", and the value "1" is set for the SSSG to be activated. Here, "n" indicates the maximum number of activatable SSSGs, for example, "4". Assuming that the SSSG index #0 is activated, the SSSG index #1 is deactivated, the SSSG index #2 is activated, and the SSSG index #3 is deactivated, the "T0 field" is set to "1", the "T1 field" is set to "0", the "T2 field" is set to "1", and the "T3 field" is set to "1", respectively.

[0130] The SSSG information field may be configured in a bitmap format targeting only the activated SSSGs. For example, the first activated SSSG is mapped to code point 1 of the SSSG information field, and the second activated SSSG is mapped to code point 2 of the SSSG information field. Assuming that the SSSG index #0 is activated, the SSSG index #1 is deactivated, the SSSG index #2 is activated, and the SSSG index #3 is deactivated, the number of bits of the SSSG information field is "2", "10" indicates the SSSG index #0, and "01" indicates the SSSG index #2.

[0131] In step S404, the base station 200 (communication unit 210) transmits a handover instruction DCI having an SSSG information field to the UE 100 on the PDCCH. The UE 100 (communication unit 110) receives the handover instruction DCI on the PDCCH. The UE 100 (control unit 120) may determine whether the detected DCI format of the DCI corresponds to the handover instruction DCI based on the field setting information set by the base station 200.

[0132] In step S405, the UE 100 (control unit 120) obtains the value set in the SSSG information field of the handover instruction DCI received in step S404. The UE 100 (control unit 120) may identify the number of bits of the SSSG information field based on the bit number setting information set by the base station 200 and then obtain the value set in the SSSG information field. Alternatively, the UE 100 (control unit 120) may identify the number of bits of the SSSG information field based on the number of SSSG indexes set in the UE 100 (that is, the number of entries in the set SSSG index list) and then obtain the value set in the SSSG information field. For example, when the number of SSSG indexes set in the UE 100 is "I", the UE 100 (control unit 120) may calculate and identify the number of bits of the SSSG information field as an integer value obtained by rounding up the decimal part of log2(I).

[0133] In step S406, the UE 100 (control unit 120) performs a handover to the SSSG having the SSSG index corresponding to the value set in the SSSG information field in the received handover instruction DCI based on the correspondence information set by the base station 200, and monitors the PDCCH according to the target SSSG. For example, in the example of FIG. 13, when the value set in the SSSG information field is "11", the UE 100 (control unit 120) determines that it has been instructed to perform a handover to the SSSG of SSSG index #3 and performs a handover to the SSSG of SSSG index #3.

[0134] Next, with reference to FIGS. 14 and 15, a first configuration example of information elements included in the RRC message in the third operation example will be described.

[0135] As shown in FIG. 14, the RRC message includes a PDCCH configuration (PDCCH-Config) information element. This information element is an information element used to set UE-specific PDCCH parameters such as a control resource set (CORESET), a search space, and additional parameters for acquiring the PDCCH.

[0136] The PDCCH configuration (PDCCH-Config) information element may include a search space set to add / modify list (searchSpaceSetToAddModList) and / or a search space set to release list (searchSpaceSetToReleaseList). The search space set to add / modify list is a list of search space sets (SEQUENCE (SIZE (1..maxNrofSearchSpaceSets-r17)) OF SearchSpaceSet-r17) to be set for the UE100. The search space set to release list is a list of search space sets (SEQUENCE (SIZE (1..maxNrofSearchSpaceSets-r17)) OF SearchSpaceSet-r17) to be released from the settings in the UE100. Here, "maxNrofSearchSpaceSets-r17" indicates the maximum number of search space sets that can be set.

[0137] As shown in Fig. 15, the "SearchSpaceSet-r17" that constitutes each entry of the SSSG addition / change list and the SSSG release list includes the "SearchSpaceSetId-r17" which is the index of the SSSG and the "searcSpaces-r17" which is each search space configuration included in this SSSG. "searcSpaces-r17" is composed of a list of search space IDs (SEQUENCE (SIZE (0..maxNrofSearchSpaces-r17)) OF SearchSpaceId) of each search space configuration included in this SSSG. The "SearchSpaceSetId-r17" which is the index of the SSSG has the number of bits of "0..maxNrofSearchSpaceSets-1-r17".

[0138] Next, with reference to Figs. 16 and 17, a second configuration example of the information element included in the RRC message in the third operation example will be described. The second configuration example indicates the SSSG to which the search space configuration belongs in each search space configuration.

[0139] As shown in Fig. 16, the PDCCH configuration (PDCCH-Config) information element can include a search space addition / change list (searchSpacesToAddModListExt2-r17). The search space addition / change list is a list consisting of 1 to 10 "SearchSpaceExt2-r17".

[0140] As shown in Fig. 17, the search space configuration (SearchSpace) information element includes a "searchSpaceSetIdList-r17" which is a list of indexes of the SSSGs associated with this search space configuration. One search space configuration can be associated with multiple SSSGs. For an SSSG that is not associated with any of the search space configurations set in the UE100, the UE100 does not monitor the PDCCH while using the SSSG.

[0141] As described above, according to the third operation example, the base station 200 receives correspondence information indicating the correspondence relationship between each SSSG index of one or more SSSGs set in the UE 100 and the value set in the SSSG information field in the switching instruction DCI that instructs the switching of the SSSG applied by the UE 100. The one or more SSSGs include at least one of the SSSG that periodically monitors the PDCCH and the SSSG that skips the monitoring of the PDCCH. Thereby, flexible power saving can be realized using various SSSGs. Also, since one SSSG information field provided in the switching instruction DCI can specify any one of a plurality of SSSGs having different search space periods or an SSSG that does not monitor the PDCCH, an increase in the size of the DCI can be suppressed even when various SSSGs are used.

[0142] (Fourth operation example) Next, with reference to FIG. 18, a fourth operation example according to the present embodiment will be described. In the fourth operation example, it is assumed that the UE 100 switches the SSSG based on a timer and three or more SSSGs can be set in the UE 100.

[0143] In the fourth operation example, the base station 200 (control unit 230) may set one of the SSSGs set in the UE 100 as the default SSSG in the UE 100. For example, the base station 200 (control unit 230) may specify one of the SSSG indexes set in the UE 100 as "defaultSSSG-Id". The default SSSG may be an SSSG determined by a predetermined rule that is shared in advance by the base station 200 and the UE 100 among the SSSGs set in the UE 100. The default SSSG may be an SSSG set in the UE 100 as the default SSSG by the base station 200.

[0144] As shown in FIG. 18, in step S501, the UE 100 (control unit 120) in which a plurality of SSSGs are set by the base station 200 monitors the PDCCH using one of the plurality of SSSGs.

[0145] In step S502, the UE 100 (communication unit 110) receives, from the base station 200 on the PDCCH, a handover instruction DCI that instructs a handover to another SSSG.

[0146] In step S503, the UE 100 (control unit 120) performs a handover to the SSSG specified by the handover instruction DCI and starts a timer (handover timer) associated with the SSSG.

[0147] In step S504, the UE 100 (control unit 120) determines whether the handover timer has expired.

[0148] When the handover timer has expired (step S504: YES), in step S505, the UE 100 (control unit 120) switches to the default SSSG among the plurality of configured SSSGs. Here, by switching to the SSSG specified as the "defaultSSSG-Id" from the base station 200, the base station 200 can grasp the SSSG to which the UE 100 has been handed over. Note that since the handover timer is a value set by the base station 200, the base station 200 manages the handover timer in the same way as the UE 100 and can grasp that the handover timer has expired in the UE 100.

[0149] If the default SSSG is not set by the base station 200 in the UE 100 (control unit 120), specifically, if the default SSSG is not explicitly specified from the base station 200 as the "defaultSSSG-Id", the default SSSG is determined according to a predetermined rule. The predetermined rule is, for example, a rule defined in the technical specifications of 3GPP and is a rule shared in advance by the base station 200 and the UE 100.

[0150] Here, the predetermined rule may be a rule for determining, as the default SSSG, the SSSG corresponding to the SSSG index with the smallest value or the SSSG corresponding to the SSSG index with the largest value among the SSSG indexes set in the UE100. For example, in the example of FIG. 13, when the rule is to use the SSSG corresponding to the SSSG index with the smallest value as the default SSSG, the UE100 (control unit 120) determines the SSSG of SSSG index #0 as the default SSSG. When the rule is to use the SSSG corresponding to the SSSG index with the largest value as the default SSSG, the UE100 (control unit 120) determines the SSSG of SSSG index #3 as the default SSSG.

[0151] As described above, the UE100 (communication unit 110) may receive, from the base station 200, correspondence relationship information indicating the correspondence relationship between the SSSG index set in the UE100 and the value set in the SSSG information field in the switching instruction DCI. The predetermined rule may be a rule for determining, as the default SSSG, the SSSG corresponding to the SSSG index indicated by a specific value (for example, "0") as the value set in the SSSG information field in the switching instruction DCI. For example, the UE100 (control unit 120) determines, as the default SSSG, the SSSG having the SSSG index indicated by the value "0" set in the SSSG information field in the switching instruction DCI.

[0152] The predetermined rule may be a rule for determining, as the default SSSG, the SSSG corresponding to the SSSG index having a predetermined value (for example, index #0) among the SSSG indexes set in the UE100.

[0153] The predetermined rule may be a rule for determining, as the default SSSG, the SSSG other than the SSSG for which monitoring of the PDCCH is skipped among the SSSGs set in the UE100. That is, the UE100 (control unit 120) may assume that the SSSG index corresponding to PDCCH skipping is not set as the default SSSG.

[0154] When DRX is set in UE100, UE100 (control unit 120) may apply a specific SSSG when switching from the reception off period to the reception on period (active time) of DRX. The predetermined rule may be a rule for determining the specific SSSG as the default SSSG. That is, UE100 (control unit 120) may determine the first SSSG for monitoring the PDCCH after the elapse of the reception off period of DRX as the default SSSG.

[0155] In the fourth operation example, UE100 (communication unit 110) may receive a scheduling DCI indicating the radio resources allocated to UE100 as a switching instruction DCI. After receiving the scheduling DCI as the switching instruction DCI, UE100 (control unit 120) may start a switching timer at the timing of switching to one SSSG (specifically, the slot for executing the SSSG switching). As described in the first operation example, UE100 (control unit 120) may hold the SSSG switching while the retransmission-related timer regarding the HARQ process is operating. For this reason, when receiving the scheduling DCI as the switching instruction DCI, the switching timer is started at the timing of executing the SSSG switching instead of the timing of receiving the switching instruction DCI.

[0156] UE100 (control unit 120) may use a common value as the value of the switching timer applied to two or more of the three or more SSSGs set in UE100. The base station 200 (control unit 230) may set a common value as the value of the switching timer applied to two or more of the three or more SSSGs set in UE100.

[0157] UE100 (control unit 120) may use individual values for each SSSG as the value of the switching timer applied to each of the SSSGs set in UE100. The base station 200 (control unit 230) may set individual switching timer setting values for each SSSG in UE100.

[0158] When the target SSSG to be switched to is an SSSG that supports PDCCH skipping, the UE 100 (control unit 120) may start a switching timer associated with the SSSG at the timing (slot) of starting the switch to the SSSG. When in the PDCCH skipping state, that is, during a predetermined period in which monitoring of the PDCCH is skipped, the resources used for PDCCH monitoring are not dedicated, and the switch to the SSSG can be started at any timing. By taking advantage of this advantage, it is possible to minimize the influence of the switching delay time without inhibiting the operation of PDCCH monitoring. Note that after the expiration of the switching timer, the UE 100 (control unit 120) may monitor assuming the default SSSG PDCCH instead.

[0159] Next, with reference to FIG. 19, a specific example 1 of the operation using the switching timer according to the fourth operation example will be described.

[0160] As shown in FIG. 19, a total of three SSSGs, namely, a default SSSG, SSSG #x, and SSSG #y, are set in the UE 100. Here, it is assumed that the base station 200 (control unit 230) sets one common switching timer value for the UE 100 for SSSG #x and SSSG #y that are not the default SSSG.

[0161] During period T11, the UE 100 (control unit 120) monitors the PDCCH using the default SSSG. The UE 100 (communication unit 110) receives non-scheduling DCI (Non-scheduling DCI) instructing a switch to SSSG #x in the last search space of period T11. Since no HARQ process occurs in the case of non-scheduling DCI, the UE 100 (control unit 120) starts a switching timer at the reception of the non-scheduling DCI.

[0162] During period T12, UE100 (control unit 120) monitors the PDCCH using SSSG#x while the switching timer is operating. SSSG#x is an SSSG with a longer search space period compared to the default SSSG. When the switching timer expires, UE100 (control unit 120) switches to the default SSSG after the elapse of the switching delay time.

[0163] During period T13, UE100 (control unit 120) monitors the PDCCH using the default SSSG. UE100 (communication unit 110) receives a scheduling DCI that instructs a switch to SSSG#y in the last search space of period T13. Since HARQ processing occurs in the case of scheduling DCI, UE100 (control unit 120) starts the switching timer at the timing (slot) when the switch to SSSG#y is executed without starting the switching timer upon receiving the scheduling DCI.

[0164] During period T14, UE100 (control unit 120) monitors the PDCCH using SSSG#y while the switching timer is operating. SSSG#y is an SSSG with a shorter search space period compared to the default SSSG. When the switching timer expires, UE100 (control unit 120) switches to the default SSSG after the elapse of the switching delay time. Then, during period T15, UE100 (control unit 120) monitors the PDCCH using the default SSSG.

[0165] Next, with reference to FIG. 20, a specific example 2 of the operation using the switching timer according to the fourth operation example will be described.

[0166] As shown in FIG. 20, a total of three SSSGs, namely, a Default SSSG, SSSG #x for PDCCH skipping, and SSSG #y for PDCCH skipping, are set in the UE 100. Here, it is assumed that the base station 200 (control unit 230) sets individual switching timer values for SSSG #x and SSSG #y, which are not the default SSSG, in the UE 100.

[0167] In period T21, the UE 100 (control unit 120) monitors the PDCCH using the default SSSG. The UE 100 (communication unit 110) receives a non-scheduling DCI that instructs a switch to SSSG #x in the last search space of period T11. Since the target SSSG #x for switching corresponds to the SSSG for PDCCH skipping, the UE 100 (control unit 120) starts a switching timer (Switching timer-1) independently set for SSSG #x at the timing (slot) when the switch to SSSG #x is executed.

[0168] In period T22, the UE 100 (control unit 120) skips the monitoring of the PDCCH while the Switching timer-1 is operating. When the Switching timer-1 expires, the UE 100 (control unit 120) switches to the default SSSG after the elapse of a switching delay.

[0169] During period T23, the UE 100 (control unit 120) monitors the PDCCH using the default SSSG. The UE 100 (communication unit 110) receives a scheduling DCI that instructs a switch to SSSG#y in the last search space of period T23. Since the target SSSG#x for switching is the SSSG corresponding to PDCCH skipping, the UE 100 (control unit 120) starts a switching timer (Switching timer-2) independently set for SSSG#y at the timing (slot) when the switch to SSSG#y is executed. The timer value of Switching timer-2 is larger than the timer value of Switching timer-1.

[0170] During period T24, the UE 100 (control unit 120) skips monitoring the PDCCH while Switching timer-2 is operating. When Switching timer-2 expires, the UE 100 (control unit 120) switches to the default SSSG after the elapse of a switching delay. Then, during period T25, the UE 100 (control unit 120) monitors the PDCCH using the default SSSG.

[0171] Thus, according to the fourth operation example, even when the UE 100 performs switching of the SSSG on a timer basis and three or more SSSGs can be set for the UE 100, by defining the default SSSG, the base station 200 can grasp the target SSSG for switching. Therefore, it becomes possible to perform switching on a timer basis for various SSSGs.

[0172] (Other Embodiments) The above-described first to fourth operation examples may be implemented separately and independently, or may be implemented by combining two or more operation examples. Also, the steps in the first to fourth operation examples do not necessarily have to be executed in chronological order along the order described in the flowchart or sequence diagram. For example, the steps in the operation may be executed in an order different from the order described as the flowchart or sequence diagram, or may be executed in parallel. Also, a part of the steps in the operation may be deleted, and additional steps may be added to the process. Furthermore, each of the above-described operation flows can be implemented by combining two or more operation flows, not limited to the case of implementing them separately and independently. For example, a part of the steps of one operation flow may be added to another operation flow, or a part of the steps of one operation flow may be replaced with a part of the steps of another operation flow.

[0173] In the above-described embodiment, the base station 200 may include a plurality of units. The plurality of units may include a first unit that hosts a higher layer included in the protocol stack and a second unit that hosts a lower layer included in the protocol stack. The higher layer may include the RRC layer, the SDAP layer, and the PDCP layer, and the lower layer may include the RLC layer, the MAC layer, and the PHY layer. The first unit may be a CU (Central Unit), and the second unit may be a DU (Distributed Unit). The plurality of units may include a third unit that performs processing below the PHY layer. The second unit may perform processing above the PHY layer. The third unit may be an RU (Radio Unit). The base station 200 may be one of the plurality of units and may be connected to other units among the plurality of units. Also, the base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

[0174] In the above-described embodiments, the mobile communication system 1 has been described by taking a mobile communication system based on NR as an example. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system compliant with any TS of LTE or other generation systems (e.g., the sixth generation) of the 3GPP standard. The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol terminations to the UE 100 in LTE. The mobile communication system 1 may be a system compliant with a TS of a standard other than the 3GPP standard.

[0175] 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 on a computer-readable medium. By using a computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Further, circuits for executing 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 (chipset, SoC).

[0176] In the above embodiments, "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 by wire. Alternatively, "transmit" may mean a combination of performing the processing of the at least one layer and physically transmitting a signal wirelessly or by wire. 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 by wire. Alternatively, "receive" may mean a combination of performing the processing of the at least one layer and physically receiving a signal wirelessly or by wire. Similarly, "obtain / acquire" may mean obtaining information from stored information, may mean obtaining information from information received from other nodes, or may mean obtaining the information by generating the information. Similarly, "include" and "comprise" do not mean including only the recited items, and may mean including only the recited items or may mean including further items in addition to the recited items. Similarly, in the present disclosure, "or" does not mean exclusive disjunction and means disjunction.

[0177] The present disclosure has been described based on examples, but it is understood that the present disclosure is not limited to such examples and structures. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and forms, and further other combinations and forms including only one element, more than one element, or less than one element thereof, are within the scope and spirit of the present disclosure.

Claims

1. Receiving from a base station (200) a radio resource control (RRC) message including first information for setting a plurality of search space set groups including a first search space set group, a second search space set group, and a third search space set group, and second information for setting one timer value for controlling monitoring of a physical downlink control channel (PDCCH) from the second search space set group to the first search space set group and for controlling monitoring of the PDCCH from the third search space set group to the first search space set group, a receiver (110) for receiving downlink control information (DCI) including an information field related to monitoring of the PDCCH from the base station (200), When monitoring the PDCCH according to the second search space set group is being performed based on a value set in the information field, if a timer set with the timer value set by the second information expires, starting monitoring of the PDCCH according to the first search space set group, a control unit (120) for starting monitoring of the PDCCH according to the first search space set group when a timer set with the timer value set by the second information expires while monitoring the PDCCH according to the third search space set group is being performed based on a value set in the information field, and comprising a communication device (100).

2. The first search space set group is identified by a group index "0", The second search space set group is identified by a group index "1", The third search space set group is identified by a group index "2" The communication device (100) according to Claim 1.

3. The timer value is set for each of one or more downlink bandwidth parts (DL BWP) set in the communication device (100) The communication device (100) according to Claim 1 or Claim 2.

4. The DCI including the information field is used for scheduling of a physical downlink shared channel (PDSCH) or for scheduling of a physical uplink shared channel (PUSCH) The communication device (100) according to claim 1 or 2.

5. Transmit to the communication device (100) a radio resource control (RRC) message including first information for setting a plurality of search space set groups including a first search space set group, a second search space set group, and a third search space set group, and second information for setting one timer value for controlling monitoring of a physical downlink control channel (PDCCH) from the second search space set group to the first search space set group and for controlling monitoring of the PDCCH from the third search space set group to the first search space set group. A transmitting unit configured to transmit to the communication device (100) a downlink control information (DCI) including an information field related to monitoring of the PDCCH. When the communication device (100) is performing monitoring of the PDCCH according to the second search space set group based on a value set in the information field, if a timer set with the timer value set by the second information expires, monitoring of the PDCCH according to the first search space set group is started. When the communication device (100) is performing monitoring of the PDCCH according to the third search space set group based on a value set in the information field, if a timer set with the timer value set by the second information expires, monitoring of the PDCCH according to the first search space set group is started. Base station (200).

6. The first search space set group is identified by a group index "0". The second search space set group is identified by a group index "1". The third search space set group is identified by a group index "2". The base station (200) according to claim 5.

7. The timer value is set for each of one or more downlink bandwidth parts (DL BWP) set in the communication device (100). The base station (200) according to claim 5 or claim 6.

8. The DCI including the information field is used for scheduling of a physical downlink shared channel (PDSCH) or scheduling of a physical uplink shared channel (PUSCH). The base station (200) according to claim 5 or 6.

9. A communication method used in a communication device (100), comprising: receiving, from a base station (200), a radio resource control (RRC) message including first information for setting a plurality of search space set groups including a first search space set group, a second search space set group, and a third search space set group, and second information for setting one timer value for controlling monitoring of a physical downlink control channel (PDCCH) from the second search space set group to the first search space set group and controlling monitoring of the PDCCH from the third search space set group to the first search space set group; when monitoring the PDCCH according to the second search space set group based on a value set in the information field and a timer set with the timer value set by the second information expires, starting to monitor the PDCCH according to the first search space set group; when monitoring the PDCCH according to the third search space set group based on a value set in the information field and a timer set with the timer value set by the second information expires, starting to monitor the PDCCH according to the first search space set group. Communication method.

10. The first search space set group is identified by a group index "0". The second search space set group is identified by a group index "1". The third search space set group is identified by a group index "2". The communication method according to claim 9.

11. The timer value is set for each of one or more downlink bandwidth parts (DL BWP) set in the communication device (100). The communication method according to claim 9 or claim 10.

12. The DCI including the information field is used for scheduling of a physical downlink shared channel (PDSCH) or scheduling of a physical uplink shared channel (PUSCH). The communication method according to claim 9 or 10.

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