WO2023112961A1 - Communication device, base station, and communication method - Google Patents

Abstract

A communication device (100) that performs wireless communication with a base station (200) comprises: a transmission unit (111) that performs CG transmission which is uplink transmission based on a configuration grant (CG) from the base station (200); and a control unit (120) which, in accordance with the CG transmission, performs a CG-caused switching process for switching a physical downlink control channel (PDCCH) monitoring state concerning the monitoring of a PDCCH. The control unit (120) performs the CG-caused switching process in accordance with expiration of a hybrid automatic repeat request (HARQ)-roundtrip time (RTT) timer, which is used for a HARQ process for uplink data transmitted by the CG transmission. The HARQ-RTT timer is a timer that defines a minimum period before the communication device (100) receives delivery confirmation information corresponding to the uplink data from the base station (200).

Description

Communication device, base station, and communication method Cross-references to related applications

This application is based on and claims the benefit of priority from patent application number 2021-205581, filed December 17, 2021, the entire contents of which are incorporated by reference. incorporated herein by.

The present disclosure relates to communication devices, base stations, and communication methods used in mobile communication systems.

In recent years, in the 3GPP (registered trademark; hereinafter the same) (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, power saving technology that reduces the power consumption of communication devices in the radio resource control (RRC) connected state has been introduced as the first technology. It is being considered for introduction into fifth generation (5G) systems.

For example, as one of the power saving techniques, in order to reduce the power consumption required for monitoring the physical downlink control channel (PDCCH) in the communication device, the physical downlink control channel (PDCCH) monitoring A process of switching the monitoring state of PDCCH (hereinafter referred to as switching process) is under consideration. For example, the communication device switches the PDCCH monitoring state to a state in which the PDCCH monitoring cycle is lengthened or the PDCCH monitoring is skipped through the switching process. In particular, in a communication device, by dynamically switching the PDCCH monitoring state during the active time in discontinuous reception (DRX) in the RRC connected state, a greater power consumption reduction effect than the power consumption reduction by DRX can be achieved. Obtainable. Such an operation of skipping PDCCH monitoring and an operation of switching PDCCH monitoring states may be referred to as PDCCH monitoring adaptation.

A method has been proposed in which a communication device performs switching processing in response to the occurrence of an opportunity to perform wireless communication with a base station. For example, the communication device switches the PDCCH monitoring state from a state of skipping PDCCH monitoring to a state of monitoring PDCCH, triggered by CG transmission, which is uplink transmission based on configured grants (CG) from the base station. (Non-Patent Document 1).

A communication device according to the first aspect is a communication device that performs wireless communication with a base station. The communication device includes a transmitting unit that performs CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station, and a PDCCH monitoring related to monitoring of a physical downlink control channel (PDCCH) according to the CG transmission a control unit that performs CG-induced switching processing for switching states. The control unit performs the CG-induced switching process in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by the CG transmission. The HARQ-RTT timer is a timer that defines the minimum period until the communication device receives acknowledgment information corresponding to the uplink data from the base station.

A base station according to the second aspect is a base station that performs wireless communication with a communication device. The base station includes a receiving unit that receives uplink data by CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station, from the communication device, and the uplink data transmitted by the CG transmission. Switching the PDCCH monitoring state for monitoring the physical downlink control channel (PDCCH) upon expiration of the HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing Switching for controlling CG-induced switching processing and a transmitting unit configured to transmit control information to the communication device. The HARQ-RTT timer is a timer that defines the minimum period until the communication device receives acknowledgment information corresponding to the uplink data from the base station.

A communication method according to the third aspect is a communication method executed by a communication device that performs wireless communication with a base station. The communication method includes a step of performing CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station; and a step of performing CG-induced switching processing for switching between. In the step of performing CG-induced switching processing, the CG-induced switching processing is performed in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted in the CG transmission. conduct. The HARQ-RTT timer is a timer that defines the minimum period until the communication device receives acknowledgment information corresponding to the uplink data from the base station.

Objects, features, advantages, etc. of the present disclosure will become clearer from the following detailed description with reference to the accompanying drawings.
FIG. 1 is a diagram showing the configuration of a mobile communication system according to an embodiment. FIG. 2 is a diagram illustrating a configuration example of a protocol stack according to the embodiment; FIG. 3 is a diagram showing an overview of radio communication operations in the mobile communication system according to the embodiment. FIG. 4 is a diagram showing an overview of PDCCH skipping according to the embodiment. FIG. 5 is a diagram showing an overview of search space set (SSSG) switching according to the embodiment. FIG. 6 is a diagram illustrating DRX and power saving states according to an embodiment. FIG. 7 is a diagram illustrating an example of SSSG switching according to the embodiment. FIG. 8 is a diagram illustrating an example of timer-based SSSG switching according to an embodiment. FIG. 9 is a diagram showing an overview of CG transmission according to the embodiment. FIG. 10 is a diagram showing the configuration of a UE according to the embodiment. FIG. 11 is a diagram showing the configuration of a base station according to the embodiment. FIG. 12 is a diagram illustrating an example of an operation sequence regarding CG-induced switching processing according to the embodiment. FIG. 13 is a diagram (Part 1) illustrating an operation example related to CG-induced switching processing according to the embodiment; FIG. 14 is a diagram (part 2) illustrating an operation example related to CG-induced switching processing according to the embodiment; FIG. 15 is a diagram illustrating a specific example 1 of CG-induced switching processing according to the embodiment. FIG. 16 is a diagram illustrating specific example 2 of the CG-induced switching process according to the embodiment.

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.

In the method in which the communication device switches the PDCCH monitoring state according to CG transmission, when the communication device autonomously switches the PDCCH monitoring state, the actual PDCCH monitoring state in the communication device and the PDCCH monitoring state recognized by the base station are changed. can be inconsistent. Therefore, after the communication device switches the PDCCH monitoring state in response to CG transmission, there is a concern that the base station cannot properly perform radio communication with the communication device.

Therefore, one object of the present disclosure is to provide a communication device, a base station, and a communication method that enable appropriate wireless communication even when the PDCCH monitoring state is switched according to CG transmission. do.

(1) Mobile communication system A mobile communication system according to this embodiment will be described.

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

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

The UE 100 is an example of a communication device. The UE 100 may be a mobile wireless communication device. UE 100 may be a device used by a user. The UE 100 may be a user equipment defined by 3GPP technical specifications. The UE 100 is, for example, a portable device such as a mobile phone terminal such as a smart phone, a tablet terminal, a notebook PC, a communication module, or a communication card. The UE 100 may be a vehicle (eg, car, train, etc.) or a device provided therein (eg, Vehicle UE). The UE 100 may be a transport body other than a vehicle (eg, a ship, an airplane, etc.) or a device provided thereon (eg, an Aerial UE). The UE 100 may be a sensor or a device attached thereto. Note that the UE 100 includes 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, and a remote terminal. , remote device, or remote unit.

NG-RAN 20 includes multiple 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 and may also represent a communication target of UE 100 . Each base station 200 can perform radio communication with the UE 100 residing in its own cell. The base station 200 communicates with the UE 100 using the RAN protocol stack. Base station 200 provides NR user plane and control plane protocol termination towards UE 100 and is connected to 5GC 30 via NG interface. Such an NR base station 200 is sometimes referred to as a gNodeB (gNB).

The 5GC 30 includes a core network device 300. The core network device 300 includes, for example, AMF (Access and Mobility Management Function) and/or UPF (User Plane Function). AMF performs mobility management of UE100. UPF provides functions specialized for user plane processing. The AMF and UPF are connected with the base station 200 via the NG interface.

Next, a configuration example of a protocol stack according to this embodiment will be described with reference to FIG.

The protocol of the wireless section between the UE 100 and the base station 200 includes a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, RRC layer.

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

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (Hybrid Automatic Repeat Request: HARQ), random access procedures, and the like. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the base station 200 via transport channels. The MAC layer of base station 200 includes a scheduler. The scheduler determines uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and allocation resources to UE 100 .

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

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

An SDAP (Service Data Adaptation Protocol) layer may be provided as an upper layer of the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer performs mapping between IP flows, which are the units in which the core network performs QoS control, and radio bearers, which are the units in which the AS (Access Stratum) performs QoS (Quality of Service) control.

The RRC layer controls logical channels, transport channels and physical channels according to radio bearer establishment, re-establishment and release. RRC signaling for various settings is transmitted between the RRC layer of UE 100 and the RRC layer of base station 200 . When there is an RRC connection between the RRC of UE 100 and the RRC of base station 200, UE 100 is in the RRC connected state. If there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in RRC idle state. When the RRC connection between the RRC of UE 100 and the RRC of base station 200 is suspended, UE 100 is in RRC inactive state.

The NAS layer located above the RRC layer performs session management and mobility management for UE100. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the core network device 300 (AMF). Note that the UE 100 has an application layer and the like in addition to the radio interface protocol.

Next, with reference to FIG. 3, an overview of wireless communication operations in the mobile communication system 1 according to this embodiment will be described.

The base station 200 configures the UE 100 with a search space corresponding to the candidate timing at which the PDCCH is provided. UE 100 in the RRC connected state monitors PDCCH in the set search space, receives downlink control information (Downlink Control Information: DCI) carried by PDCCH, and assigns resources (scheduling) indicated by DCI. According to the physical downlink shared channel (PDSCH) reception and / or physical uplink shared channel (PUSCH) is transmitted. For example, the UE 100 may monitor a set of PDCCH candidates according to the corresponding search space. That is, according to the corresponding search space, the UE 100 is a control resource set (CORESET) in the downlink bandwidth part (DL BWP) in the serving cell in which PDCCH monitoring is set, and is a PDCCH candidate. set may be monitored. Here, monitoring may refer to decoding each of the PDCCH candidates according to the monitored DCI format.

As shown in FIG. 3, in step S1, the base station 200 transmits an RRC message including PDCCH settings (PDCCH settings) to the UE 100, and performs various PDCCH settings for the UE 100. This RRC message is a UE-specific RRC message, and may be, for example, an RRC Reconfiguration message. Here, among the settings related to PDCCH, the search space settings include 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 (for example, the number of consecutive slots), and PDCCH monitoring. symbols for, aggregation level, search space type, DCI format, etc. Here, each search space (each set of search spaces) may be associated with one CORESET. Also, the search space setting may be set for each of one or more DL BWPs. Here, the search space type may include a UE-specific search space (USS) and/or a UE common search space (CSS).

DCI formats include scheduling DCI formats used for PDSCH or PUSCH scheduling and non-scheduling DCI formats not used for such scheduling. DCI transmitted in a scheduling DCI format is called scheduling DCI, and DCI transmitted in a non-scheduling DCI format is called non-scheduling DCI.

Scheduling DCI formats include a downlink DCI format used for PDSCH scheduling (eg, DCI format 1_0, DCI format 1_1, DCI format 1_2) and an uplink DCI format used for PUSCH scheduling (eg, DCI format 0_0, DCI format 0_1 and DCI format 0_2). The scheduling DCI may be UE-specific DCI that is sent for each UE. For example, the scheduling DCI may be transmitted by applying an RNTI (Radio Network Temporary Identifier) assigned to each UE.

On the other hand, non-scheduling DCI formats include, for example, DCI format 2_0 and DCI format 2_6. The non-scheduling DCI may be a DCI that can be transmitted to multiple UEs 100 at once. For example, non-scheduling DCI may be transmitted by applying a common RNTI to multiple UEs 100 .

In step S2, the UE 100 starts monitoring PDCCH in the search space set by the base station 200. For example, 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 are configured in the UE 100, and the 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, base station 200 may configure UE 100 to monitor PDCCH candidates for DCI format 1_0 and DCI format 0_0 when CSS is configured for a certain search space. Also, base station 200 may configure UE 100 to monitor PDCCH candidates for DCI format 2_0 when CSS is configured for a certain search space. In addition, base station 200 instructs UE 100 to monitor PDCCH candidates for DCI format 1_0 and DCI format 0_0 or DCI format 1_1 and DCI format 0_1 when USS is configured for a certain search space. can be set to Also, base station 200 instructs UE 100 to monitor PDCCH candidates for DCI format 1_0 and DCI format 0_0 or DCI format 1_2 and DCI format 0_2 when USS is configured for a certain search space. can be set to

In step S3, the UE 100 receives and detects DCI or PDCCH addressed to itself from the base station 200. For example, the UE 100 uses the C-RNTI (Cell-Radio Network Temporary Identifier (RNTI)) and MCS-C-RNTI (Modulation and Coding Scheme-C-RNTI) assigned to the UE 100 from the base station 200, or the CS-RNTI ( Blind decoding of PDCCH is performed using Configured Scheduling-RNTI), and successfully decoded DCI is acquired as DCI addressed to its own UE. Here, the DCI transmitted from the base station 200 is added with CRC (Cyclic Redundancy Check) parity bits scrambled by C-RNTI and MCS-C-RNTI or CS-RNTI.

When the DCI indicates PDSCH scheduling, in step S4, the UE 100 receives downlink data from the base station 200 on the scheduled PDSCH. If the DCI indicates PUSCH scheduling, the UE 100 transmits uplink data to the base station 200 on the scheduled PUSCH in step S5. Here, downlink data is also referred to as downlink shared channel (DL-SCH) data. Uplink data is also referred to as uplink-shared channel (UL-SCH) data. Here, the downlink shared channel and the uplink shared channel are transport channels, and PDSCH and PUSCH are physical channels. For example, downlink data (DL-SCH data) is mapped to PDSCH, and uplink data (UL-SCH data) is mapped to PUSCH.

(2) Overview of Power Saving Technology An overview of the power saving technology according to this embodiment will be described.

First, an overview of PDCCH skipping according to this embodiment will be described with reference to FIG. It is assumed below that the UE 100 is in the RRC connected state.

First, the UE 100 monitors the PDCCH provided at predetermined intervals in the search space based on the search space setting set by the base station 200 . In the present embodiment, such a PDCCH monitoring state regarding PDCCH monitoring in UE 100 may be referred to as a PDCCH monitoring execution state for monitoring PDCCH.

Second, the base station 200 transmits to the UE 100 a skip instruction DCI that instructs PDCCH skipping. Skip instruction DCI is an example of switching instruction DCI. A skip indication DCI may be a scheduling DCI or a non-scheduling DCI.

Third, the UE 100 skips PDCCH monitoring for a predetermined period in response to receiving the skip instruction DCI from the base station 200 . The predetermined period for skipping PDCCH monitoring may be set by higher layer signaling (RRC message). The predetermined period may be determined by a timer value (that is, a setting value of a switching timer), or may be determined by the number of consecutive slots or the number of consecutive search spaces. The predetermined period may be referred to as a skip period. Such PDCCH skipping reduces the power consumption required for the UE 100 to monitor the PDCCH, and can achieve dynamic power saving. Note that PDCCH skipping may mean skipping PDCCH monitoring, and PDCCH skipping may be referred to as PDCCH monitoring skipping. In this embodiment, such a PDCCH monitoring state in the UE 100 may be referred to as a PDCCH skipping state.

Next, an overview of search space set group switching (SSSG switching) according to this embodiment will be described with reference to FIG.

First, the base station 200 configures multiple search space sets, which are sets of settings related to search spaces, in the UE 100 through higher layer signaling (RRC messages). A set of settings related to such a search space is called a Search Space Set (SSS) or a Search Space Set Group (SSSG), but in the following it will be mainly called SSSG. . One SSSG includes one or more search space settings and is identified by an SSSG index. In the example of FIG. 5, base station 200 has SSSG#0 (first search space set) in which search spaces are provided at a predetermined cycle, and SSSG#1 (second search space set) in which search spaces are provided at a cycle longer than the predetermined cycle. space set) shall be set in the UE 100. Here, an example is shown in which the base station 200 sets two SSSGs, SSSG#0 and SSSG#1, to the UE 100. Three or more SSSGs are set for each of one or more BWPs (for example, DL BWP). You may set to UE100. Note that setting a plurality of SSSGs (or three or more SSSGs) in the UE 100 may mean setting a plurality of SSSGs (or three or more SSSGs) for one BWP, or a plurality of may mean setting multiple SSSGs (or three or more SSSGs) for each BWP. Also, considering that search spaces include UE-specific search spaces and/or UE-common search spaces as described above, a set of settings related to UE-specific search spaces may be referred to as a UE-specific search space set. , the set of configurations for UE-common search spaces may be referred to as a UE-common search space set.

Second, the UE 100 monitors the PDCCH provided at predetermined intervals in the search space based on SSSG#0.

Third, the base station 200 transmits to the UE 100 a switching instruction DCI that instructs SSSG switching. The switching instruction DCI may be a scheduling DCI or a non-scheduling DCI. That is, the base station 200 uses DCI to instruct the UE 100 to switch from SSSG#0 to SSSG#1.

Fourth, the UE 100 starts switching to SSSG#1 in response to receiving the switching instruction DCI. UE 100 performs switching to SSSG#1 in a symbol after a switching delay time (Switch delay) from the last symbol of PDCCH in SSSG#0. Such a switching delay time may be set from the base station 200 to the UE 100 by higher layer signaling (RRC message).

Fifth, based on SSSG#1, UE 100 monitors PDCCHs provided in a cycle longer than a predetermined cycle in search spaces. Such search space set switching reduces the power consumption required for UE 100 to monitor the PDCCH, and can achieve dynamic power saving.

Note that switching from SSSG#1 to SSSG#0 may be instructed by the base station 200 using DCI in the same manner as switching from SSSG#0 to SSSG#1, or the UE 100 may switch from SSSG#1 using a timer. You may switch to SSSG#0. The timer value of such a switching timer (Switching timer) is set from the base station 200 to the UE 100 by higher layer signaling (RRC message). The UE 100 starts monitoring the PDCCH in SSSG#1 in response to detection of the switching instruction DCI to SSSG#1, sets the value of the switching timer to the value set by the upper layer, and activates the switching timer. UE 100 decrements the value of the switching timer, stops monitoring PDCCH in SSSG#1 when the switching timer expires, and starts monitoring PDCCH in SSSG#0 after a switch delay time.

"#0" in SSSG#0 and "#1" in SSSG#1 indicate indexes (also called search space group IDs) for sets (groups) of search spaces. That is, one or more search space sets may be associated with a set (group) of search spaces identified by an index. For example, base station 200 may configure a set (group) of search spaces for UE 100 by configuring an index associated with the one or more search space sets. 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 to which one or more search space sets are associated.

In search space set switching, one SSSG set in the UE 100 is set to have no search space, and switching to the one SSSG is indicated by DCI, thereby realizing the same operation as the PDCCH skipping described above. Also, a search space is set in one SSSG set in the UE 100, and no monitoring opportunity for the search space is set (or a parameter related to the monitoring opportunity is set to a predetermined value (e.g., "0" or "Null"). ), an operation similar to the PDCCH skipping described above may be realized. Hereinafter, in order to facilitate the explanation, as a setting for realizing the same operation as the PDCCH skipping described above, it will be described that there is no search space in one SSSG, but no monitoring opportunity is set (or monitoring setting a parameter related to the opportunity to a predetermined value). Also, in other SSSGs set in the UE 100, it is possible to set them to have a long search space cycle, and to instruct switching to the one SSSG by DCI. In order to realize such an operation, UE 100 is configured with a total of three SSSGs: an SSSG with a normal search space period, an SSSG with no search space period, and an SSSG with a long search space period. Flexible power saving can be realized by setting such various SSSGs in the UE 100 and instructing switching of SSSGs by DCI.

Next, regarding this embodiment, discontinuous reception (DRX) will be described, and the power saving state will be described with reference to FIG.

When DRX is configured in the UE 100, the UE 100 discontinuously monitors the PDCCH using the DRX operation. Specifically, the DRX operation is controlled by the following DRX parameters.
- DRX cycle: Defines the cycle in which the UE 100 wakes up.
On duration (on-duration): This is the period during which the UE 100 waits to receive the PDCCH after waking up. If the UE 100 successfully decodes the PDCCH, the UE 100 remains awake and starts an inactivity-timer.
Inactivity timer: Defines the time period during which the UE 100 waits after the last successful PDCCH decoding and sleeps again when the PDCCH decoding fails. In addition to this, after the inactivity timer expires and a predetermined set value DRX-SlotOffset elapses, the ON duration may be started. FIG. 6 corresponds to the operation with the set value of DRX-SlotOffset set to zero.
• Retransmission timer: defines the time interval during which retransmissions are expected.

In this way, the UE 100 configured with DRX does not need to monitor the PDCCH in the sleep state (that is, the reception off period), so the power consumption of the UE 100 can be reduced. On the other hand, the UE 100 waits to receive the PDCCH and monitors the PDCCH in the search space during the active time. The active time is any of the on duration timer (drx-onDurationTimer), the inactivity timer (drx-InactivityTimer), the downlink retransmission timer (drx-RetransmissionTimerDL), and the uplink retransmission timer (drx-RetransmissionTimerUL) is in operation. It's time.

By performing the above-described PDCCH skipping or search space set switching within the active time of DRX, it is possible to dynamically switch to the power saving state during the active time, and the power consumption is greater than the low power consumption achieved by DRX. A reduction effect can be obtained.

Next, an example of PDCCH monitoring adaptation according to this embodiment will be described with reference to FIG. PDCCH supervisory adaptation is a generic term for PDCCH skipping and SSSG switching. That is, in this embodiment, PDCCH monitoring adaptation may be replaced by PDCCH skipping and/or SSSG switching. In PDCCH monitoring adaptation, a process of switching the PDCCH monitoring state for PDCCH monitoring may be performed.

Here, a plurality of SSSGs having different search space cycles (different PDCCH cycles) and various SSSGs including SSSGs having no search space, one or more SSSGs can be set in the UE 100, and the SSSG's It is assumed that flexible power saving is realized by indicating switching (that is, switching of PDCCH monitoring state) with DCI. Here, in this embodiment, a plurality of SSSGs having different search space cycles (different PDCCH cycles) will be described, but it is possible to set the same search space cycle (different PDCCH cycles) for a plurality of SSSGs. is of course.

As shown in FIG. 7, in step S11, the base station 200 transmits one or more RRC messages to the UE100. The one or more RRC messages may include a dedicated RRC message (eg, RRCReconfiguration message) sent for each UE. UE 100 receives the RRC message.

The RRC message includes PDCCH monitoring adaptation settings (hereinafter referred to as PMA settings). The PMA settings may be settings for performing PDCCH monitoring adaptation. PMA setting includes information for setting SSSG, information for setting a switching timer for switching SSSG, information for setting a duration related to PDCCH monitoring, and setting cases related to PDCCH monitoring state switching. may include at least one of information for

Note that the information for setting the case may be information for setting the case (also referred to as operation) of PDCCH monitoring adaptation. As described below, it may be specified to perform PDCCH skipping (ie PDCCH skipping only), for example for the case of PDCCH monitoring adaptation. It may also be specified to perform SSSG switching (ie SSSG switching only) as a case of PDCCH monitoring adaptation. It may also be specified to perform PDCCH skipping and SSSG switching as a case of PDCCH monitoring adaptation. That is, cases may be defined corresponding to operations performed as PDCCH monitoring adaptation.

Information for setting SSSG (hereinafter referred to as SSSG setting information as appropriate) includes, for example, information for setting SSSG to which PDCCH skipping is applied, and information for setting SSSG to which SSSG switching is applied. At least one may be included. The SSSG setting information may also include information for setting at least one of a default SSSG (eg, SSSG#0) and a non-default SSSG that is not the default SSSG. That is, SSSG configuration information may be configured for default SSSG and/or non-default SSSG. The SSSG configuration information may include SSSG information configured for each downlink BWP, and may include SSSG information configured for each downlink serving cell. That is, the SSSG configuration information may be configured for the downlink BWP and/or the downlink serving cell.

The SSSG configuration information may further include a search space configuration associated with each SSSG index (which may be referred to as a group index) corresponding to each SSSG. A search space setting includes one or more search space settings. Each search space configuration includes at least one of search space period, search space offset, search space duration (e.g., number of consecutive slots), symbols for PDCCH monitoring, aggregation level, search space type, and DCI format. OK.

Information for setting a switching timer for switching between SSSGs (hereinafter referred to as switching timer information as appropriate) may include information on switching timers set for each SSSG. The switch timer information may include switch timer information for the default SSSG and may include switch timer information for the non-default SSSG. That is, switching timer information may be configured for default SSSG and/or non-default SSSG. Note that the switching timer may not be set for the default SSSG. Also, the switching timer information may include switching timer information configured for each downlink BWP, and may include switching timer information configured for each downlink serving cell. That is, the switching timer information may be configured for the downlink BWP and/or the downlink serving cell. The switching timer information may include a timer set value of the switching timer.

Information for setting a period related to PDCCH monitoring (hereinafter referred to as monitoring period information as appropriate) may include information on a period set for each SSSG. The monitoring period information may include period information for the default SSSG and may include period information for the non-default SSSG. That is, monitoring period information may be set for default SSSGs and/or non-default SSSGs. The monitoring period information may include information on a period set for each downlink BWP, or may include information on a period set for each downlink serving cell. That is, the monitoring period information may be configured for the downlink BWP and/or the downlink serving cell. The set period may be a skip period for skipping PDCCH monitoring.

A case related to PDCCH monitoring state switching, specifically, information for setting a case of PDCCH monitoring adaptation (hereinafter referred to as case setting information as appropriate) includes case information set for each downlink BWP. Alternatively, it may include case information configured for each downlink serving cell. That is, the case configuration information may be configured for the downlink BWP and/or the downlink serving cell. An example of the correspondence between cases and PDCCH monitoring adaptation (ie, PDCCH monitoring state) behavior is shown in Table 1. Table 1 shows an example of DCI notification contents in each case.

By setting case #1, PDCCH skipping (that is, execution of PDCCH skipping only) is set as PDCCH monitoring adaptation. The configuration for case #2 configures two different durations of SSSG switching (ie performing SSSG switching only) as PDCCH monitoring adaptation. The configuration for case #3 configures SSSG switching for three different durations (ie performing SSSG switching only) as a PDCCH monitoring adaptation. With the configuration of case #4, two different periods of SSSG switching and PDCCH skipping (ie performing PDCCH skipping and SSSG switching) are configured as PDCCH monitoring adaptations. In case #4, M (set to 1 or 2) indicates the number of periods set based on the monitoring period information. That is, M corresponds to period X. Period X may be referred to as a skip period.

In each case, the PDCCH monitoring adaptation applied by UE 100 (that is, SSSG switching and/or PDCCH skipping) information field in the switching instruction DCI (hereinafter, PDCCH monitoring adaptation notification field:) is set to It is associated with the operation (behavior) of the UE 100 shown. Operations of the UE 100 may be defined as follows.
• PDCCH skipping is not activated in Beh1.
• For Beh1A, PDCCH skipping means stopping PDCCH monitoring for period X.
• Beh2 stops monitoring the search space sets associated with SSSG#1 and SSSG#2 (if configured) and monitors the search space set associated with SSSG#0.
• Beh2A stops monitoring the search space sets associated with SSSG#0 and SSSG#2 (if configured) and monitors the search space set associated with SSSG#1.
• In Beh2B, stop monitoring the search space set associated with SSSG#0 and SSSG#1 (if configured) and monitor the search space set associated with SSSG#2.

The information indicating the correspondence relationship in Table 1 may be stored in advance in each of the UE 100 and the base station 200, or may be notified from the base station 200 to the UE 100 by an RRC message.

When case #1 is configured in the UE 100, the UE 100 has one for PDCCH monitoring for each of one or more downlink BWPs (or each of one or more SSSGs) in a serving cell. Alternatively, multiple periods (including skip periods) may be set.

When case #2 or case #3 is configured in the UE 100, the UE 100 has one serving cell for each of one or more downlink BWPs (or each of one or more SSSGs). One or more group indices (SSSG indices) may be configured.

When case #4 is configured in the UE 100, the UE 100 has PDCCH for each of one or more downlink BWPs (or each of one or more SSSGs) in a certain serving cell, in a certain serving cell. One or more periods (including skip periods) for monitoring may be set. Also, in the UE 100, one or more group indexes (SSSG indexes) are set for each of one or more downlink BWPs (or each of one or more SSSGs) in a serving cell. you can Note that the PDCCH monitoring adaptation notification field in DCI for PDCCH monitoring is defined as 2 bits.

The RRC message may include field settings indicating the presence or absence of the PDCCH monitoring adaptation notification field for each of one or more DCI formats. The switching indication DCI is a DCI having a DCI format indicating that there is a PDCCH monitoring adaptation notification field by field setting. The presence/absence of the PDCCH monitoring adaptation notification field may be configured commonly or independently for non-scheduling DCI and/or scheduling DCI. The presence/absence of the PDCCH monitoring adaptation notification field (presence/absence) may be set commonly for DCI format 1_1 and DCI format 0_1, and commonly for DCI format 1_2 and DCI format 0_2. The presence or absence (presence/absence) of the PDCCH monitoring adaptation notification field may be set commonly for DCI format 1_1 and DCI format 1_2, and commonly for DCI format 0_1 and DCI format 0_2. Here, the field setting indicating presence/absence of the PDCCH monitoring adaptation notification field may be replaced with the PMA setting. That is, the presence of the PDCCH monitoring adaptation notification field in one or more DCI formats may be indicated by configuring the PMA settings for the UE 100 . For example, UE 100 may identify that one or more DCI formats have a PDCCH monitoring adaptation notification field based on the PMA configuration being configured.

The RRC message may include a bit number setting that indicates the number of bits in the PDCCH supervisory adaptation notification field for each of one or more DCI formats. For non-scheduling DCI and/or scheduling DCI, the number of bits of the PDCCH monitoring adaptation notification field may be directly configured commonly or independently. The number of bits of the PDCCH monitoring adaptation notification field may be configured 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, a PDCCH supervisory adaptation notification field of up to 2 bits is configured for DCI format 1_1 and/or DCI format 0_1, and/or a PDCCH supervisory adaptation notification field of 1 bit is configured for DCI format 1_2 and DCI format 0_2. may be set. The number of bits of the PDCCH monitoring adaptation notification field may be configured commonly for DCI format 1_1 and DCI format 1_2, and commonly for DCI format 0_1 and DCI format 0_2. Here, the number of bits setting indicating the number of bits of the PDCCH supervisory adaptation notification field may be replaced with the PMA setting. That is, the number of bits of the PDCCH monitoring adaptation notification field included in one or more DCI formats may be determined by configuring the PMA settings for the UE 100 . For example, UE 100 may determine the number of bits of the PDCCH monitoring adaptation notification field included in one or more DCI formats according to the number of SSSGs configured based on information for configuring SSSGs. Also, UE 100 may determine the number of bits of the PDCCH monitoring adaptation notification field included in one or more DCI formats according to the number of periods set based on the monitoring period information. Also, UE 100 may determine the number of bits of the PDCCH monitoring adaptation notification field included in one or more DCI formats, depending on the case set based on the case setting information (for example, shown in Table 1. may determine the number of bits to be stored).

In step S12, the UE 100 stores the information set by the base station 200.

In step S13, the base station 200 transmits a switching instruction DCI having a PDCCH monitoring adaptation notification field to the UE 100 on the PDCCH. UE 100 receives the switching instruction DCI on the PDCCH. The UE 100 may determine whether or not the DCI format of the detected DCI corresponds to the switching instruction DCI, based on field settings set by the base station 200 .

In step S14, the UE 100 acquires the value set in the PDCCH monitoring adaptation notification field of the switching instruction DCI received in step S13. UE 100 may specify the number of bits in the PDCCH monitoring adaptation notification field based on the bit number setting set by base station 200 and then acquire the value set in the PDCCH monitoring adaptation notification field. Here, as described above, for example, the UE 100 is based on the number of SSSG indexes set in the UE 100 (i.e., the number of entries in the set SSSG index (list)), and the number of bits of the PDCCH monitoring adaptation notification field is specified. Additionally, the value set in the PDCCH supervisory adaptation notification field may be obtained. For example, when the number of SSSG indexes set in UE 100 is set to "I", UE 100 calculates and identifies the number of bits of the PDCCH monitoring adaptation notification field by an integer value rounded up after the decimal point of log2 (I). good too.

In step S15, the UE 100 changes the PDCCH monitoring state to the state corresponding to the value set in the PDCCH monitoring adaptation notification field (hereinafter referred to as the PDCCH monitoring adaptation notification field value) in the received switching instruction DCI based on the set case. switch. An operation example of the UE 100 according to the number of bits of the PDCCH monitoring adaptation notification field in each case is shown below.

Case #1: PDCCH Supervisory Adaptation Notification field in DCI for PDCCH Monitoring is 1 bit If the PDCCH Supervisory Adaptation Notification field value is '0', no PDCCH skipping is performed.
If the PDCCH monitoring adaptation notification field value is '1', PDCCH skipping is performed during the configured period (the period of the first value).

Case #1: PDCCH supervisory adaptation notification field in DCI for PDCCH supervision is 2 bits If the PDCCH supervisory adaptation notification field value is '00', no PDCCH skipping is performed.
If the PDCCH monitoring adaptation notification field value is '01', PDCCH skipping is performed during the configured period (the period of the first value).
If the PDCCH monitoring adaptation notification field value is '10', PDCCH skipping is performed during the configured period (second value period).
If the PDCCH monitoring adaptation notification field value is '11', PDCCH skipping is performed during the configured period (the period of the third value).

Case #2: If the PDCCH supervisory adaptation notification field in the DCI for PDCCH supervision is 1 bit If the PDCCH supervisory adaptation notification field value is '0', the PDCCH according to the search space set corresponding to group index #0 Start monitoring and stop monitoring the PDCCH according to the search space set corresponding to the other group index value.
If the PDCCH monitoring adaptation notification field value is '1', start monitoring PDCCH according to the search space set corresponding to group index #1, and start monitoring PDCCH according to the search space set corresponding to other group index values. Stop monitoring.

Case #3: If the PDCCH supervisory adaptation notification field in the DCI for PDCCH supervision is 2 bits If the PDCCH supervisory adaptation notification field value is '00', the PDCCH according to the search space set corresponding to group index #0 Start monitoring and stop monitoring the PDCCH according to the search space set corresponding to the other group index value.
If the PDCCH monitoring adaptation notification field value is '01', start monitoring PDCCH according to the search space set corresponding to group index #1, and start monitoring PDCCH according to the search space set corresponding to other group index values. Stop monitoring.
If the PDCCH monitoring adaptation notification field value is '10', start monitoring the PDCCH according to the search space set corresponding to group index #2, and start monitoring the PDCCH according to the search space set corresponding to the other group index value. Stop monitoring.
The definition of when the PDCCH Supervisory Adaptation Notification field value is '11' is reserved.

Case #4: If the number of periods for PDCCH monitoring is set to '1' If the PDCCH Monitoring Adaptation Notification field value is '00', PDCCH monitoring according to the search space set corresponding to group index #0. and stop monitoring the PDCCH according to the search space set corresponding to the other group index value.
If the PDCCH monitoring adaptation notification field value is '01', start monitoring PDCCH according to the search space set corresponding to group index #1, and start monitoring PDCCH according to the search space set corresponding to other group index values. Stop monitoring.
If the PDCCH monitoring adaptation notification field value is '10', PDCCH skipping is performed during the configured period (the period of the first value).
The definition of when the PDCCH Supervisory Adaptation Notification field value is '11' is reserved.

Case #4: If the number of periods for PDCCH monitoring is set to '2' If the PDCCH Monitoring Adaptation Notification field value is '00', PDCCH monitoring according to the search space set corresponding to group index #0. and stop monitoring the PDCCH according to the search space set corresponding to the other group index value.
If the PDCCH monitoring adaptation notification field value is '01', start monitoring PDCCH according to the search space set corresponding to group index #1, and start monitoring PDCCH according to the search space set corresponding to other group index values. Stop monitoring.
If the PDCCH monitoring adaptation notification field value is '10', PDCCH skipping is performed during the configured period (the period of the first value).
If the PDCCH monitoring adaptation notification field value is '11', PDCCH skipping is performed during the configured period (second value period).

Next, an example of timer-based SSSG switching according to this embodiment will be described with reference to FIG. Here, it is assumed that the UE 100 switches between SSSGs on a timer basis and three or more SSSGs can be configured in the UE 100 .

The base station 200 may set one of the SSSGs set in the UE 100 as a default SSSG in the UE 100. For example, the base station 200 may specify one of the SSSG indices set in the UE 100 as "defaultSSSG-Id". For example, the base station 200 may set the 'defaultSSSG-Id' using an RRC message. That is, the base station 200 may configure the default SSSG for the UE 100 using information included in the RRC message. The default SSSG may be an SSSG determined according to a predetermined rule shared in advance by the base station 200 and the UE 100 among SSSGs set in the UE 100 . The default SSSG may be the SSSG set in the UE 100 by the base station 200 as the default SSSG.

As shown in FIG. 8, in step S21, the UE 100 for which multiple SSSGs have been set by the base station 200 monitors the PDCCH using one of the multiple SSSGs.

In step S22, the UE 100 receives a switching instruction DCI that instructs switching to another SSSG from the base station 200 on the PDCCH.

In step S23, the UE 100 switches to the SSSG specified by the switching instruction DCI and activates the timer (switching timer) associated with the SSSG.

In step S24, the UE 100 determines whether the switching timer has expired.

When the switching timer expires (step S24: YES), in step S25, the UE 100 switches to the default SSSG among the multiple set SSSGs. Here, by switching to the SSSG specified by the base station 200 as “defaultSSSG-Id”, the base station 200 can grasp the SSSG to which the UE 100 is switched. Since the switching timer is a value set by the base station 200, the base station 200 manages the switching timer in the same manner as the UE 100, and can recognize that the switching timer has expired in the UE 100.

If the default SSSG is not set by the base station 200, specifically, if the default SSSG is not explicitly specified by the base station 200 as "defaultSSSG-Id", the UE 100 determines the default SSSG according to a predetermined rule. do. For example, if the RRC message does not contain information for setting the default SSSG, the UE 100 may determine the default SSSG according to a predetermined rule. The predetermined rule is, for example, a rule defined by 3GPP technical specifications, and a rule shared in advance by the base station 200 and the UE 100 .

Here, the predetermined rule is the SSSG corresponding to the SSSG index with the smallest value among the SSSG indexes set in the UE 100, or the SSSG corresponding to the SSSG index with the largest value. good. For example, if the rule is to set the SSSG corresponding to the SSSG index with the smallest value as the default SSSG, the UE 100 determines the SSSG with SSSG index #0 as the default SSSG. If the rule is to set the SSSG corresponding to the SSSG index with the largest value as the default SSSG, the UE 100 determines the SSSG of SSSG index #4 as the default SSSG.

As described above, the UE 100 may receive from the base station 200 correspondence information indicating the correspondence between the SSSG index set in the UE 100 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 (eg, "0") set in the SSSG information field in the switching instruction DCI. For example, the UE 100 determines, as the default SSSG, an SSSG having an SSSG index in which the value set in the SSSG information field in the switching instruction DCI is "0".

The predetermined rule may be a rule that determines the SSSG corresponding to the SSSG index (for example, index #0) having a predetermined value among the SSSG indices set in the UE 100 as the default SSSG.

The predetermined rule may be a rule for determining, among the SSSGs set in the UE 100, SSSGs other than SSSGs skipping PDCCH monitoring as default SSSGs. That is, UE 100 may assume that the SSSG index corresponding to PDCCH skipping is not set as the default SSSG.

When DRX is configured in the UE 100, the UE 100 may apply a specific SSSG when switching from a DRX reception off period to a reception on period (active time). The predetermined rule may be a rule that determines that particular SSSG as the default SSSG. That is, the UE 100 may determine the first SSSG to monitor the PDCCH after the DRX reception off period has elapsed as the default SSSG. For example, the base station 200 may transmit an RRC message including information for setting the specific SSSG, and the UE 100 may determine the specific SSSG as the default SSSG. In addition, the base station 200 transmits an RRC message including information for setting the default SSSG, and the UE 100 uses the default SSSG as the first SSSG to monitor the PDCCH after the DRX reception off period has passed. good too.

The UE 100 may receive a scheduling DCI indicating radio resources allocated to the UE 100 as a switching instruction DCI. After receiving the scheduling DCI as the switching instruction DCI, the UE 100 may start the switching timer at the timing of switching to one SSSG (specifically, the slot for performing SSSG switching).

The UE 100 may use a common value as the switching timer value applied to two or more of the three or more SSSGs set in the UE 100 . The base station 200 may set a common value as the switching timer value applied to two or more SSSGs among the three or more SSSGs set in the UE 100 .

The UE 100 may use an individual value for each SSSG as the switching timer value applied to each SSSG set in the UE 100 . The base station 200 may set an individual switching timer setting value in the UE 100 for each SSSG.

When the switching destination SSSG is an SSSG that supports PDCCH skipping, the UE 100 may activate the switching timer associated with the SSSG at the timing (slot) at which switching to the SSSG is started. When in the PDCCH skipping state, that is, during a predetermined period during which PDCCH monitoring is skipped, resources used for PDCCH monitoring are not dedicated, and switching to the relevant SSSG can be started at any timing. Taking advantage of this advantage, it is possible to minimize the effect of the switching delay time without disturbing the PDCCH monitoring operation. Note that the UE 100 may monitor the PDDCH assuming the default SSSG after the switching timer expires.

(3) Outline of CG Transmission An outline of CG transmission according to the present embodiment will be described.

An overview of CG transmission according to the present embodiment will be described with reference to FIG. In order to achieve low-delay communication, the UE 100 performs uplink data transmission directly by PDCCH in addition to uplink transmission based on dynamic uplink grant (grant), without dynamic uplink grant Uplink transmission (that is, CG transmission) is performed. CG transmission is uplink transmission based on configured grants (CG) from the base station 200 . A CG transmission may be referred to as a CG-PUSCH transmission. CG transmission may include transmission of MAC PDU (MAC Protocol Data Unit) on PUSCH.

CG transmission includes type 1 CG transmission and type 2 CG transmission. In type 1 CG transmission, uplink transmission is permitted by RRC signaling (RRC message). For Type 1 CG transmission, the actual uplink grant may be set via RRC. When the type 1 CG transmission is set by the RRC message, the UE 100 performs CG transmission using the set radio resource (hereinafter referred to as CG resource).

On the other hand, in type 2 CG transmission, uplink transmission is permitted by RRC signaling (RRC message) and DCI. For Type 2 CG transmissions, the actual uplink grants may be provided via PDCCH (destined for CS-RNTI). UE 100 performs CG transmission using the set CG resource when CG transmission is activated (effective) by DCI after type 1 CG transmission is set by the RRC message. The UE 100 does not perform CG transmission when CG transmission is deactivated (disabled). Note that CG transmission can be deactivated by DCI.

In step S31, the base station 200 transmits to the UE 100 an RRC message including CG settings for setting parameters used for CG transmission. UE 100 receives an RRC message including CG settings from base station 200 . UE 100 stores the information set by the RRC message.

CG configuration may be an information element used to configure uplink transmission without dynamic grant. A CG configuration may include, for example, information identifying a CG resource.

In step S32, when the base station 200 sets type 2 CG transmission to the UE 100 as CG transmission, it may transmit DCI for activating CG transmission. UE 100 may receive DCI from base station 200 . When type 2 CG transmission is set as CG transmission, UE 100 activates type 2 CG transmission in response to reception of DCI for activating CG transmission.

In step S33, the UE 100 detects a CG transmission trigger. A CG transmission trigger may be the occurrence of a transmission opportunity due to CG resources. In addition, the CG transmission trigger is generated when uplink data and/or a buffer status report (BSR) to be transmitted to the base station 200 is generated, and when the uplink data to be transmitted to the base station 200 is MAC of the UE 100 It may be either having arrived at the layer or instructing CG transmission from the MAC layer to the physical (PHY) layer in the UE 100 .

Note that even if CG transmission is configured, if there is no uplink data in the transmission buffer, the UE 100 determines that the CG transmission trigger is not detected even if there is a transmission opportunity using the CG resource. good too. As described above, in this embodiment, CG transmission may be MAC PDU transmission. That is, for example, when there is no uplink data in the transmission buffer and CG transmission (transmission of MAC PDUs to the base station 200) is not executed (triggered), the PDCCH monitoring state need not be switched. That is, in this embodiment, uplink data may correspond to MAC PDUs. Uplink data (that is, MAC PDU) may correspond to user data.

In step S34, the UE 100 performs CG transmission to the base station 200 on PUSCH in response to the CG transmission trigger, based on the CG settings set in step S31.

In step S35, the base station 200 may transmit acknowledgment information (ACK or NACK) to the UE 100 according to the reception status of uplink data by CG transmission. Also, the base station 200 may instruct retransmission of CG transmission. For example, base station 200 may indicate retransmission of CG transmission using a DCI format (eg, DCI format 0_1 or 0_2) with CRC parity bits scrambled by CS-RNTI. For example, retransmission of CG transmission is indicated using a New Data Indicator (NDI) included in the DCI format (for example, by setting the value of the New Data Indicator (NDI) to 1). good too. That is, base station 200 may instruct retransmission of CG transmission using PDCCH to which CRC parity bits scrambled by CS-RNTI are added. In this embodiment, the acknowledgment information may include a DCI format (which may be PDCCH). That is, the acknowledgment information may include the DCI format (PDCCH) used to indicate retransmission. Here, the DCI format (PDCCH) used to instruct retransmission is a retransmission grant (uplink Also called link HARQ retransmission grant). Also, the acknowledgment information may be ACK or NACK.

　UE 100 receives the acknowledgment information. Based on the acknowledgment information, the UE 100 performs CG transmission retransmission processing (eg, hybrid automatic repeat request (HARQ) processing for uplink data (or simply uplink)). For example, the UE 100 may perform retransmission of CG transmission based on reception of the DCI format used to instruct retransmission of CG transmission (that is, based on detection of the PDCCH in which the DCI format is transmitted). . That is, after executing CG transmission, UE 100 may attempt to receive a DCI format used to instruct retransmission of CG transmission. That is, UE 100 may monitor the PDCCH used to instruct retransmission of CG transmission after executing CG transmission.

As described above, the UE 100 performs CG transmission, which is uplink transmission to the base station 200, in response to a predetermined transmission trigger. Such CG transmission may occur in a power saving state (ie, a state of lengthening the PDCCH monitoring period or skipping PDCCH monitoring) by performing PDCCH monitoring adaptation. After the CG transmission, wireless communication is performed between the UE 100 and the base station 200. Therefore, it is preferable to switch the PDCCH monitoring state from the power saving state with the transmission trigger of the CG transmission as an opportunity to exit the power saving state. .

Here, when the UE 100 switches the PDCCH monitoring state according to CG transmission, when the UE 100 autonomously switches the PDCCH monitoring state, the actual PDCCH monitoring state in the UE 100 and the PDCCH monitoring state recognized by the base station 200 are changed. can be inconsistent. Therefore, there is a concern that the base station 200 cannot properly perform radio communication with the UE 100 after the UE 100 switches the PDCCH monitoring state. Therefore, in this embodiment, it is possible to switch the PDCCH monitoring state based on CG transmission under the control of the base station 200 .

Also, when the UE 100 switches the PDCCH monitoring state according to CG transmission, the behavior of the MAC layer (in particular, DRX operation related to PDCCH monitoring adaptation) is not defined in the 3GPP technical specifications. Therefore, a discrepancy may occur between the actual PDCCH monitoring state in UE 100 and the PDCCH monitoring state recognized by base station 200 . Therefore, there is a concern that the base station 200 cannot properly perform radio communication with the UE 100 after the UE 100 switches the PDCCH monitoring state.

Here, the "PDCCH monitoring state" in this embodiment may include skipping PDCCH monitoring and/or performing PDCCH monitoring in the configured SSSG. For example, switching the PDCCH monitoring state may include switching the operation from skipping PDCCH monitoring to monitoring PDCCH with the configured SSSG. Also, switching the PDCCH monitoring state may include switching the operation from the operation of monitoring the PDCCH in the configured SSSG to the operation of skipping the monitoring of the PDCCH. In addition, switching the PDCCH monitoring state includes switching the operation from the operation of monitoring the PDCCH in the set first SSSG to the operation of monitoring the PDCCH in the set second SSSG. good too.

Also, switching the PDCCH monitoring state may include switching the SSSG used for PDCCH monitoring. For example, switching the PDCCH monitoring state may include switching the SSSG from the SSSG configured for PDCCH skipping to the SSSG configured for PDCCH monitoring. Also, switching the PDCCH monitoring state may include switching the SSSG from the SSSG configured for PDCCH monitoring to the SSSG configured for PDCCH skipping. Also, switching the PDCCH monitoring state may include switching the SSSG from the first SSSG set for PDCCH monitoring to the second SSSG set for PDCCH monitoring.

That is, in the present embodiment, switching the PDCCH monitoring state may correspond to execution of PDCCH monitoring adaptation. Here, in the present embodiment, the SSSG used for PDCCH monitoring is also referred to as a PDCCH monitoring state for ease of explanation. Also, as described above, the set SSSG includes a default SSSG.

(4) Configuration of User Equipment A configuration of the UE 100 according to the present embodiment will be described with reference to FIG. UE 100 includes communication unit 110 and control unit 120 .

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 transmitter 111 and at least one receiver 112 . The transmitting section 111 and the receiving section 112 may be configured including an antenna and an RF circuit. The antenna converts a signal into radio waves and radiates the radio waves into space. Also, the antenna receives radio waves in space and converts the radio waves into signals. The RF circuitry performs analog processing of signals transmitted and received through the antenna. The RF circuitry may include high frequency filters, amplifiers, modulators, low pass filters, and the like.

The control unit 120 performs various controls in the UE 100. Control unit 120 controls communication with base station 200 via 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 that stores the program. The processor may execute a program to operate the control unit 120 . The control unit 120 may include a digital signal processor that performs digital processing of signals transmitted and received through the antenna and RF circuitry. The digital processing includes processing of the protocol stack of the RAN. Note that the memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. The memory is ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access Mem ory) and flash memory. All or part of the memory may be included within the processor.

The UE 100 according to this embodiment performs wireless communication with the base station 200. The transmitting unit 111 performs CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station. The control unit 120 performs CG-induced switching processing for switching the PDCCH monitoring state regarding monitoring of the physical downlink control channel (PDCCH) according to CG transmission or a CG transmission trigger. The control unit 120 performs CG-induced switching processing in response to expiration of the HARQ-RTT timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by CG transmission. The HARQ-RTT timer is a timer that defines the minimum period until the UE 100 receives acknowledgment information corresponding to uplink data from the base station. For example, the HARQ-RTT timer may be defined as the minimum period before a DCI format (PDCCH) used to indicate retransmissions is expected. That is, the HARQ-RTT timer may be defined by the MAC entity as the minimum duration before an uplink HARQ retransmission grant is expected. Here, the HARQ-RTT timer may be defined (set) for each uplink HARQ process. As a result, the base station 200 recognizes that the UE 100 performs CG-induced switching processing in response to the expiration of the HARQ-RTT timer, thereby switching the PDCCH monitoring state based on CG transmission under the control of the base station 200. Therefore, even when the PDCCH monitoring state is switched, radio communication can be appropriately performed. Further, since the acknowledgment information from the base station 200 does not arrive until the HARQ-RTT timer expires, the UE 100 can maintain the power saving state while the acknowledgment information does not arrive.

Further, when the PDCCH monitoring state is a PDCCH skipping state in which PDCCH is not monitored, the control unit 120 may switch to the state of monitoring PDCCH by CG-based switching processing based on the expiration of the HARQ-RTT timer. . As a result, UE 100 no longer skips PDCCH monitoring, and can receive PDCCH generated after CG transmission.

In addition, control section 120 has a skip period timer associated with the period of the PDCCH skipping state (that is, the period for skipping PDCCH monitoring), and when the skip period timer is in operation, the PDCCH skipping state is set. may be maintained. Here, the control unit 120 may stop the skip period timer based on the expiration of the HARQ-RTT timer. That is, the control unit 120 may stop the skip period timer and switch to the state of monitoring the PDCCH based on the expiration of the HARQ-RTT timer. As a result, UE 100 no longer skips PDCCH monitoring, and can monitor PDCCH generated after CG transmission.

Also, when the current search space set group (SSSG) is in the PDCCH skipping state, the control unit 120 may switch to the state of monitoring the PDCCH by CG-based switching processing upon expiration of the HARQ-RTT timer. As a result, UE 100 no longer skips PDCCH monitoring, and can monitor PDCCH generated after CG transmission.

Also, the control unit 120 may switch to a predetermined SSSG as the SSSG for monitoring the PDCCH in response to the expiration of the HARQ-RTT timer. This enables monitoring of PDCCHs occurring after CG transmission in a given SSSG.

For example, if a default SSSG is set, the control unit 120 may switch to the default SSSG as the predetermined SSSG upon expiration of the HARQ-RTT timer. The base station 200 can understand that PDCCH monitoring is performed in the configured default SSSG.

In addition, the control unit 120 may switch to the SSSG set by the base station 200 using the RRC message (for example, the PMA setting included in the RRC message) as the predetermined SSSG in response to the expiration of the HARQ-RTT timer. . For example, if the default SSSG is not set, the control unit 120 may switch to a predetermined SSSG set by the base station 200 upon expiration of the HARQ-RTT timer. The base station 200 can understand that PDCCH monitoring will be performed in a predetermined SSSG set by the base station 200 when the default SSSG is not set.

Also, the receiving unit 112 may receive switching control information for controlling CG-induced switching processing. The control unit 120 controls the CG-induced switching process based on the switching control information. As a result, switching of the PDCCH monitoring state based on CG transmission can be performed under the control of the base station 200, and even when the PDCCH monitoring state is switched, radio communication can be appropriately performed.

Also, the switching control information may be information regarding whether to enable CG-based switching processing. The control unit 120 may perform the CG-induced switching process based on the switching control information indicating that the CG-induced switching process is enabled. As a result, the base station 200 explicitly indicates whether the CG-induced switching process is valid or invalid, and furthermore, a discrepancy occurs between the actual PDCCH monitoring state in the UE 100 and the PDCCH monitoring state recognized by the base station 200. can be reduced.

(5) Configuration of Base Station The configuration of the base station 200 according to this embodiment will be described with reference to FIG. Base station 200 has communication unit 210 , network interface 220 , and control unit 230 .

For example, the communication unit 210 receives radio signals from the UE 100 and transmits radio signals to the UE 100. The communication unit 210 has at least one transmitter 211 and at least one receiver 212 . The transmitting section 211 and the receiving section 212 may be configured including an antenna and an RF circuit. The antenna converts a signal into radio waves and radiates the radio waves into space. Also, the antenna receives radio waves in space and converts the radio waves into signals. The RF circuitry performs analog processing of signals transmitted and received through the antenna. The RF circuitry may include high frequency filters, amplifiers, modulators, low pass filters, and the like.

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

The control unit 230 performs various controls in the base station 200. The control unit 230 controls communication with the UE 100 via the communication unit 210, for example. Also, the control unit 230 controls communication with nodes (for example, adjacent base stations, core network device 300) via the network interface 220, for example. 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 programs and a memory storing the programs. The processor may execute a program to operate the controller 230 . Control unit 230 may include a digital signal processor that performs digital processing of signals transmitted and received through the antenna and RF circuitry. The digital processing includes processing of the protocol stack of the RAN. Note that the memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. All or part of the memory may be included within the processor.

The base station 200 according to this embodiment performs wireless communication with the UE 100. In the base station 200 , the receiving unit 212 receives from the UE 100 uplink data by CG transmission, which is uplink transmission based on the configuration grant (CG) from the base station 200 . The transmission unit 211 transmits PDCCH related to monitoring of a physical downlink control channel (PDCCH) in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by CG transmission. Switching control information for controlling CG-induced switching processing for switching the monitoring state is transmitted to the UE 100 . The HARQ-RTT timer is a timer that defines the minimum period until the UE 100 receives acknowledgment information corresponding to uplink data from the base station. As a result, the base station 200 recognizes that the UE 100 performs CG-induced switching processing in response to the expiration of the HARQ-RTT timer, thereby switching the PDCCH monitoring state based on CG transmission under the control of the base station 200. Therefore, even when the PDCCH monitoring state is switched, radio communication can be appropriately performed. Further, since the acknowledgment information from the base station 200 does not arrive until the HARQ-RTT timer expires, the UE 100 can maintain the power saving state while the acknowledgment information does not arrive.

(6) CG Caused Switching Processing Assuming the configuration and operation described above, the CG caused switching processing according to the present embodiment will be described. Therefore, the UE 100 performs switching processing for switching the PDCCH monitoring state according to CG transmission among multiple types of uplink transmission.

(6.1) Operation Sequence Example Regarding CG-Induced Switching Processing An operation sequence example concerning the CG-induced switching processing according to the present embodiment will be described with reference to FIG. In this operation sequence example, the UE 100 (control unit 120) switches the PDCCH monitoring state after CG transmission by performing CG-induced switching processing according to CG transmission.

In step S101, the base station 200 (transmitting section 211) transmits an RRC message to the UE100. The RRC message may be a dedicated RRC message (eg, RRCReconfiguration message) sent for each UE. UE 100 (receiving unit 112) receives the RRC message.

The RRC message includes switching control information for controlling switching processing for switching the PDCCH monitoring state according to at least one of the multiple types of uplink transmission. The switching control information is included in an information element commonly applicable to multiple types of uplink transmission. The switching control information may be included as the information element, for example, in PDCCH configuration (PDCCH-Config) for setting UE-specific PDCCH parameters.

The switching control information may include common parameters (for example, common settings) commonly applied to switching processes corresponding to multiple types of uplink transmission. Therefore, the common parameters are, for example, CG-induced switching processing, SR-induced switching processing for switching the PDCCH monitoring state according to a scheduling request (SR), and RACH-induced switching for switching the PDCCH monitoring state according to RACH transmission (or PRACH transmission). It may be commonly applied to control processing. This allows the UE 100 (control unit 120) to execute various switching processes based on the common parameter, triggered by at least one of the multiple types of uplink transmission.

The switching control information may include individual parameters (for example, individual settings) individually applied to each of the switching processes corresponding to multiple types of uplink transmission. Therefore, the individual parameters are, for example, parameters applied only to control the CG-induced switching process, parameters applied only to control the SR-induced switching process, and parameters applied only to control the RACH-induced switching process. may include at least any of the parameters

Individual parameters may indicate settings that are not set by common parameters. Alternatively, individual parameters may indicate settings that are prioritized over common parameters. Also, the individual parameter may indicate whether or not to enable the switching process in at least one of the multiple types of uplink transmission. For example, the individual parameter may include 1-bit flag information indicating whether to enable or disable the CG-based switching process. By this means, the UE 100 (control unit 120) can execute various effective switching processes triggered by at least one of the plurality of types of uplink transmission based on the individual parameter. Note that the common parameter may include 1-bit flag information indicating whether to enable or disable each switching process.

Also, the RRC message may include a CG setting (ConfiguredGrantConfig) for configuring CG transmission. The CG settings may contain individual parameters that apply only to control the CG-triggered switching process.

Therefore, the PDCCH configuration may include common parameters and individual parameters. The CG configuration may contain individual parameters that are not included in the PDCCH configuration. Also, the PDCCH configuration may include only common parameters and the CG configuration may include dedicated parameters.

Upon receiving the switching control information, the UE 100 (control unit 120) may determine that switching processing based on uplink transmission has been enabled. When receiving the switching control information, the UE 100 (control unit 120) may determine that the CG-induced switching process is enabled.

The switching control information may, for example, configure PDCCH monitoring adaptation (or execution of the PDCCH monitoring adaptation) based on uplink transmission. The switching control information may also configure PDCCH supervisory adaptation (or execution of such PDCCH supervisory adaptation) when type 2 CG transmission is enabled (activated).

Also, the switching control information may include PDCCH monitoring adaptation settings (PMA settings). Therefore, the switching control information may include at least one of SSSG configuration information, switching timer information, monitoring period information, and case configuration information. The UE 100 (control unit 120) may determine that the CG-induced switching process has been activated when the RRC message includes the PMA setting.

Also, the switching control information may be included only in the CG configuration without being included in the PDCCH configuration. In this case, the switching control information may be information for controlling the CG-induced switching process. The switching control information included in the CG configuration may not include information for controlling switching processing according to other uplink transmissions.

Also, the switching control information may be information regarding whether to enable CG-based switching processing. The UE 100 (control unit 120) may perform the CG-induced switching process based on the switching control information indicating that the CG-induced switching process is enabled.

Also, the UE 100 (control unit 120) may control not to perform the CG-induced switching process when the RRC message does not include switching control information. For example, the UE 100 (control unit 120) is not set to enable the CG-induced switching process, and/or the PDCCH monitoring state (for example, SSSG) of the switching destination when performing the CG-induced switching process is set. If not, CG-induced switching processing is not performed even if CG transmission is performed. This can prevent the actual PDCCH monitoring state in UE 100 and the PDCCH monitoring state recognized by base station 200 from being inconsistent.

Note that the RRC message may include information indicating the setting for switching the PDCCH monitoring state in step S104 (that is, the setting for switching the PDCCH monitoring state at a trigger different from the uplink transmission (or the trigger for the uplink transmission)).

The RRC message may contain DRX settings for setting up DRX. The DRX settings may be included in a separate RRC message from the RRC message containing the CG settings. DRX is thereby configured in the UE 100 . The UE 100 (control unit 120) performs DRX operation based on the DRX setting.

The DRX setting is the value of the uplink HARQ-Round Trip Time (RTT) timer (drx-HARQ-RTT-TimerUL) used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by CG transmission (that is, timer value).

As described above, the HARQ-RTT timer (drx-HARQ-RTT-TimerUL) is a timer defined as the minimum period until UE 100 receives acknowledgment information corresponding to uplink data from base station 200. good. Also, the HARQ-RTT timer may be specified as the minimum period until a UL HARQ retransmission grant is expected as acknowledgment information for each uplink HARQ process. For example, for the HARQ-RTT timer, the timer value may be indicated by the value of the number of BWP symbols in which the transport block is transmitted from the UE 100.

Note that the switching control information may be information for controlling CG-induced switching processing in response to expiration of the HARQ-RTT timer, that is, information for controlling CG-induced switching processing triggered by expiration of the HARQ-RTT timer. In addition to this information, the switching control information may include, for example, information for controlling CG-induced switching processing in response to a CG transmission trigger. The switching control information may be information common to CG-triggered switching processing caused by CG transmission, that is, according to CG transmission.

In step S102, the base station 200 (transmitting unit 211) may transmit DCI for activating CG transmission when type 2 CG transmission is set to the UE 100 as CG transmission. The UE 100 (receiving unit 112) may receive the DCI. The UE 100 (control unit 230) may enable CG transmission in response to reception of DCI.

After receiving the setting for CG transmission, the UE 100 (receiving unit 112) may receive DCI for activating or deactivating CG transmission. When CG transmission is activated based on DCI, the UE 100 (control unit 120) may perform CG-induced switching processing based on switching control information. Thereby, the UE 100 can maintain the power saving state when CG transmission is not actually performed.

In step S103, the base station 200 (transmitting section 211) transmits a switching instruction DCI that instructs PDCCH skipping or SSSG switching to the UE 100 on the PDCCH. UE 100 (receiving unit 112) receives the switching instruction DCI.

In step S104, the UE 100 (control unit 120) switches the PDCCH monitoring state in response to receiving the switching instruction DCI. When PDCCH skipping is configured, UE 100 (control section 120) may skip monitoring of PDCCH over a predetermined period in response to reception of switching instruction DCI (skip instruction DCI). When SSSG switching is set, the UE 100 (control unit 120) may switch to the SSSG indicated by the switching instruction DCI in response to receiving the switching instruction DCI. As a result, UE 100 enters a power saving state in which power consumption required for PDCCH monitoring is reduced.

At step S105, the UE 100 (control unit 120) detects a CG transmission trigger.

In step S106, the UE 100 (transmitting unit 111) transmits uplink data to the base station 200 on the PUCCH in response to the CG transmission trigger based on the CG settings set in step S101. The base station 200 (receiving unit 212) receives uplink data by CG transmission.

In step S107, the UE 100 (control unit 120) starts the HARQ-RTT timer. UE 100 (control unit 120) receives MAC PDU by CG transmission based on uplink configuration grant, and sends LBT (Listen-before-talk) failure indication from low layer (that is, physical layer) to MAC layer HARQ-RTT timer may be started if not received in UE 100 (control unit 120) starts the HARQ-RTT timer for HARQ processing corresponding to the corresponding CG transmission (PUSCH transmission) at the first symbol after the end of the first transmission (within the bundle). good.

At step S108, the HARQ-RTT timer expires.

In step S109, the UE 100 (control unit 120) switches the PDCCH monitoring state according to CG transmission (CG-induced switching processing). Specifically, the UE 100 (control unit 120) performs CG switching processing in response to expiration of the uplink HARQ-RTT timer started in response to CG transmission. The UE 100 (control unit 120) can control CG switching processing based on the switching control information.

CG-induced switching processing is processing for switching the PDCCH monitoring state from the first monitoring state to the second monitoring state. The first monitoring state corresponds to the power saving state described above. The second monitoring state is a state in which the PDCCH is monitored more frequently than in the first monitoring state. This makes it easier to deal with wireless communication (data communication) that occurs after CG transmission. That is, the UE 100 (control unit 120) may perform the above-described PDCCH skipping and/or SSSG switching based on CG transmission (or CG transmission trigger). Also, the CG-induced switching process may correspond to PDCCH skipping and/or SSSG switching based on CG transmission (or CG transmission triggers).

For example, the first monitoring state may be a state in which PDCCH is monitored in a first period, and the second monitoring state may be a state in which PDCCH is monitored in a second period shorter than the first period. That is, in the second monitoring state, the search space period interval may be shorter than in the first monitoring state. For example, UE 100 (control unit 120), SSSG switching is set, after the DCI instructs switching to SSSG having a long PDCCH monitoring cycle, in response to CG transmission, to SSSG having a short PDCCH monitoring cycle switch.

Also, the first monitoring state may be a PDCCH skipping state in which PDCCH is not monitored (that is, PDCCH skipping), and the second monitoring state may be a state in which PDCCH is periodically monitored. Therefore, the CG switching process may be a process of switching the PDCCH monitoring state from the PDCCH skipping state to the PDCCH monitoring state (that is, the PDCCH monitoring execution state). For example, the UE 100 (control unit 120) is set to PDCCH skipping, and after being instructed by the DCI to perform PDCCH skipping, switches to the state of monitoring the PDCCH according to CG transmission. Note that the UE 100 (control unit 120) may stop or cancel execution of PDCCH skipping as a process of switching to the PDCCH monitoring execution state.

The UE 100 (control unit 120) may perform CG-induced switching processing only when performing CG transmission when the UE 100 itself is in the power saving state. That is, the UE 100 (control unit 120) does not need to perform CG-induced switching processing when performing CG transmission when the UE 100 itself is not in the power saving state. Alternatively, the UE 100 (control unit 120) may perform CG-induced switching processing only when CG transmission is performed in a state in which PDCCH skipping and/or SSSG switching are set. That is, UE 100 (control unit 120) does not need to perform CG-induced switching processing when PDCCH skipping and/or SSSG switching are not set. In this way, when the UE 100 (the control unit 120) performs CG transmission and the PDCCH monitoring state is the PDCCH skipping state, the UE 100 may control the CG-induced switching process based on the switching control information.

When the UE 100 (control unit 120) performs CG transmission, the PDCCH monitoring state applies the SSSG whose search space cycle is equal to or greater than a predetermined value among a plurality of search space set groups (SSSG) having different search space cycles. If it is, the CG-induced switching process may be controlled based on the switching control information. The switching control information may contain information indicating a predetermined value.

The UE 100 (control unit 120) may perform the CG-induced switching process only when the switching control information indicates that the CG-induced switching process should be enabled. When the UE 100 (control unit 120) performs the CG-induced switching process based on the switching control information indicating that the CG-induced switching process is enabled, the UE 100 switches to a predetermined PDCCH monitoring state in the CG-induced switching process. may The predefined PDCCH monitoring state may be the default SSSG described above.

When the PDCCH monitoring state (for example, SSSG) to be switched to by the CG-induced switching process is designated by the switching control information, the UE 100 (control unit 120) may switch to the PDCCH monitoring state designated by the switching control information. For example, when the switching control information includes an index indicating the SSSG after switching by the CG-induced switching process, the UE 100 (control unit 120) switches to the SSSG indicated by the index.

Further, when the PDCCH monitoring state is a PDCCH skipping state in which PDCCH is not monitored, the UE 100 (control unit 120) shifts to a state of monitoring PDCCH by CG-based switching processing based on the expiration of the HARQ-RTT timer. You can switch.

Specifically, the UE 100 (control unit 120) holds a skip period timer (that is, switching timer) associated with the period of the PDCCH skipping state. A skipping duration timer may be referred to as a PDCCH skipping duration timer. UE 100 (control unit 120) maintains the PDCCH skipping state when the skip period timer is in operation. Then, based on the expiration of the HARQ-RTT timer, the skip period timer may be stopped, as shown in FIG. 13 (A1 of FIG. 13). UE 100 (control unit 120) may cancel the skip period timer based on the expiration of the HARQ-RTT timer. That is, the control unit 120 may stop the skip period timer and switch to the state of monitoring the PDCCH based on the expiration of the HARQ-RTT timer. As a result, UE 100 (control section 120) stops maintaining the PDCCH skipping state by stopping the skip period timer, and switches the PDCCH monitoring state from the PDCCH skipping state.

In addition, as shown in FIG. 13 (B1), UE 100 (control unit 120), if the skip period timer is not set by RRC (RRC message or RRC signaling), or if the skip period timer is set by RRC However, if the skip period timer is not running, it may monitor the PDCCH on the serving cell of the DRX group during the active period.

Further, as shown in FIG. 14 (A2), UE 100 (control unit 120) is in the PDCCH skipping state in the current search space set group (SSSG), according to the expiration of the HARQ-RTT timer, CG-induced The switching process may switch to a PDCCH monitoring execution state that monitors the PDCCH. Specifically, UE 100 (control unit 120) switches to a predetermined SSSG that monitors PDCCH upon expiration of the HARQ-RTT timer.

For example, if a default SSSG is set, the UE 100 (control unit 120) may switch to the default SSSG as a predetermined SSSG upon expiration of the HARQ-RTT timer. In addition, UE 100 (control unit 120), in response to the expiration of the HARQ-RTT timer, as a predetermined SSSG, by the base station 200 RRC message (eg, PMA setting included in the RRC message) to the SSSG set using You can switch. For example, UE 100 (control unit 120), if the default SSSG is not set, according to the expiration of the HARQ-RTT timer, predetermined SSSG set by the base station 200 (for example, SSSG # 0 ). Here, the predetermined SSSG set by the base station 200 may be an SSSG other than SSSG#0.

In addition, as shown in FIG. 14 (B2), the UE 100 (control unit 120), if SSSG is not set by RRC (RRC message or RRC signaling), or SSSG is set by RRC, If there is no PDCCH skipping state (ie PDCCH monitoring is not skipped) in the current SSSG, it may monitor the PDCCH on the serving cell of the DRX group during active time.

In step S110, the base station 200 (transmitting unit 211) transmits acknowledgment information to the UE 100 according to the reception status of uplink data by CG transmission. UE 100 (receiving unit 112) can receive acknowledgment information from base station 200 by switching to the PDCCH monitoring execution state by CG-induced switching processing. For example, the UE 100 (receiving section 112) can monitor the PDCCH used to instruct retransmission of CG transmission by switching to the PDCCH monitoring execution state by the CG-induced switching process.

(6.2) Specific Example of CG-Induced Switching Processing A specific example 1 of the CG-induced switching processing according to the present embodiment will be described with reference to FIG. As described above, the CG-induced switching process is a process of switching the PDCCH monitoring state from the first monitoring state to the second monitoring state. The first monitoring state corresponds to the power saving state described above. In this specific example 1, the first monitoring state is a state in which PDCCH is monitored in a first period, and the second monitoring state is a state in which PDCCH is monitored in a second period shorter than the first period. .

At time t11, UE 100 (receiving section 112) receives a switching instruction DCI that instructs SSSG from base station 200 in downlink BWP in a serving cell.

At time t12, the UE 100 (control unit 120) starts applying the instructed SSSG (that is, starts the first monitoring state) in response to receiving the switching instruction DCI. The UE 100 (control unit 120) starts a first timer that determines the duration of the first monitoring state when starting the first monitoring state. A period Z, for example, is set as a timer value in the first timer. The timer value (timer set value) of the first timer may be set from the base station 200 to the UE 100 by an RRC message.

At time t13, the UE 100 (transmitting section 111) transmits uplink data to the base station 200 by CG transmission in the uplink BWP in the serving cell. The UE 100 (control unit 120) performs CG-induced switching processing to switch to a predetermined SSSG in response to CG transmission and/or expiration of the HARQ-RTT timer (that is, starts the second monitoring state). The predetermined SSSG may be an SSSG set by the base station 200 according to switching control information, a default SSSG (defaultSearchSpaceSet), or a first SSSG (firstSearchSpaceSet).

The UE 100 (control unit 120) stops the first timer when performing the CG-induced switching process. Stopping the first timer prevents switching to the default SSSG due to expiration of the first timer.

The UE 100 (control unit 120) starts a second timer that determines the duration of the second monitoring state when performing the CG-induced switching process. A period Y, for example, is set as a timer value in the second timer. The timer value (timer setting value) of the second timer may be set from the base station 200 to the UE 100 by an RRC message. The UE 100 (control unit 120) starts the second timer in which the timer value is set when performing the CG-induced switching process. This allows the base station 200 to control the duration of the second monitoring state.

The UE 100 (control unit 120) may restart the second timer in response to CG transmission or a CG transmission trigger in the second monitoring state. Since data communication occurs due to CG transmission, the duration of the second monitoring state can be extended by restarting the second timer.

The UE 100 (control unit 120) switches to a predetermined PDCCH monitoring state upon expiration of the second timer. That is, the UE 100 (control unit 120) terminates the second monitoring state when the period Y expires. The predetermined PDCCH monitoring state to switch to upon expiration of the second timer may be the default SSSG (defaultSearchSpaceSet) or the first SSSG (firstSearchSpaceSet).

A specific example 2 of the CG-induced switching process according to the present embodiment will be described with reference to FIG. In this specific example 2, the first monitoring state is a state in which PDCCH is not monitored (that is, PDCCH skipping state), and the second monitoring state is a state in which PDCCH is periodically monitored.

At time t21, UE 100 (receiving section 112) receives from base station 200 a switching instruction DCI that instructs PDCCH skipping in downlink BWP in a certain serving cell.

At time t22, the UE 100 (control unit 120) starts PDCCH skipping (that is, starts the first monitoring state) in response to receiving the switching instruction DCI. The UE 100 (control unit 120) starts a first timer that determines the duration of the first monitoring state when starting the first monitoring state. A period X, for example, is set as a timer value in the first timer. The timer value (timer set value) of the first timer may be set from the base station 200 to the UE 100 by an RRC message. Note that the first timer corresponds to the skip period timer.

At time t23, the UE 100 (transmitting section 111) transmits uplink data to the base station 200 by CG transmission in the uplink BWP in the serving cell. The UE 100 (control unit 120) performs CG-induced switching processing to switch to a predetermined SSSG in response to CG transmission and/or expiration of the HARQ-RTT timer (that is, starts the second monitoring state). As a result, PDCCH skipping ends and PDCCH monitoring is started (restarted). The predetermined SSSG may be an SSSG set by the base station 200 according to switching control information, a default SSSG (defaultSearchSpaceSet), or a first SSSG (firstSearchSpaceSet).

The UE 100 (control unit 120) stops the first timer when performing the CG-induced switching process. Stopping the first timer prevents switching to the default SSSG due to expiration of the first timer.

The UE 100 (control unit 120) starts a second timer that determines the duration of the second monitoring state when performing the CG-induced switching process. A period Y, for example, is set as a timer value in the second timer. The timer value (timer setting value) of the second timer may be set from the base station 200 to the UE 100 by an RRC message. The UE 100 (control unit 120) starts the second timer in which the timer value is set when performing the CG-induced switching process. This allows the base station 200 to control the duration of the second monitoring state.

The UE 100 (control unit 120) may restart the second timer in response to CG transmission or a CG transmission trigger in the second monitoring state. Since data communication occurs due to CG transmission, the duration of the second monitoring state can be extended by restarting the second timer.

The UE 100 (control unit 120) switches to a predetermined PDCCH monitoring state upon expiration of the second timer. That is, the UE 100 (control unit 120) terminates the second monitoring state when the period Y expires. The predetermined PDCCH monitoring state to switch to upon expiration of the second timer may be the default SSSG (defaultSearchSpaceSet) or the first SSSG (firstSearchSpaceSet).

(7) Other Embodiments In the above embodiments, for example, "uplink transmission" may be replaced with "voluntary uplink transmission."

The operation sequences (and operation flows) in the above-described embodiments do not necessarily have to be executed in chronological order according to the order described in the flow diagrams or sequence diagrams. For example, the steps in the operations may be performed out of order or in parallel with the order illustrated in the flow diagrams or sequence diagrams. Also, some steps in the operation may be omitted and additional steps may be added to the process. Further, the operation sequences (and operation flows) in the above-described embodiments may be implemented independently, or two or more operation sequences (and operation flows) may be combined and implemented. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow.

In the above-described embodiment, the base station 200 may include multiple units. The plurality of units may include a first unit hosting a higher layer included in the protocol stack and a second unit hosting a lower layer included in the protocol stack. The upper layers may include the RRC layer, the SDAP layer and the PDCP layer, and the lower layers 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). Base station 200 may be one of a plurality of units, and may be connected to other units of the plurality of units. Also, the base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

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

A program that causes a computer to execute each process performed by the UE 100 or the base station 200 may be provided. The program may be recorded on a computer readable medium. A computer readable medium allows the installation of the program on the 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, but may be, for example, a recording medium such as CD-ROM (Compact Disk Read Only Memory) or DVD-ROM (Digital Versatile Disc Read Only Memory). good. Also, circuits that execute each process performed by the UE 100 or the base station 200 may be integrated, and at least a part of the UE 100 or the base station 200 may be configured as a semiconductor integrated circuit (chipset, SoC (System On Chip)).

In the above embodiments, "transmit" may mean performing at least one layer of processing in the protocol stack used for transmission, or physically transmitting the signal wirelessly or by wire. may mean sending to Alternatively, "transmitting" may mean a combination of performing the at least one layer of processing and physically transmitting the signal wirelessly or by wire. Similarly, "receive" may mean performing processing of at least one layer in the protocol stack used for reception, or physically receiving a signal wirelessly or by wire. may mean that Alternatively, "receiving" may mean a combination of performing the at least one layer of processing and physically receiving the signal wirelessly or by wire. Similarly, "obtain/acquire" may mean obtaining information among stored information, and may mean obtaining information among information received from other nodes. Alternatively, it may mean obtaining the information by generating the information. Similarly, references to "based on" and "depending on/in response to" are used unless otherwise specified. does not mean The phrase "based on" means both "based only on" and "based at least in part on." Similarly, the phrase "depending on" means both "only depending on" and "at least partially depending on." Similarly, "include" and "comprise" are not meant to include only the recited items, and may include only the recited items or in addition to the recited items. Means that it may contain further items. Similarly, in the present disclosure, "or" does not mean exclusive OR, but means logical OR. Furthermore, any references to elements using the "first," "second," etc. designations used in this disclosure do not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, reference to a first and second element does not imply that only two elements can be employed therein or that the first element must precede the second element in any way. In this disclosure, when articles are added by translation, such as a, an, and the in English, these articles are used in plural unless the context clearly indicates otherwise. shall include things.

Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

(Appendix)
Features related to the above-described embodiments are added.

(Appendix 1)
A communication device (100) that performs wireless communication with a base station (200),
a transmission unit (111) that performs CG transmission, which is uplink transmission based on the configuration grant (CG) from the base station (200);
A control unit (120) that performs CG-induced switching processing to switch the PDCCH monitoring state related to monitoring of the physical downlink control channel (PDCCH) according to the CG transmission,
The control unit (120) performs the CG-induced switching process in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by the CG transmission. ,
The HARQ-RTT timer is a timer that defines a minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200). The communication device (100).

(Appendix 2)
When the PDCCH monitoring state is a PDCCH skipping state in which the PDCCH is not monitored, the control unit (120) monitors the PDCCH by the CG-based switching process based on the expiration of the HARQ-RTT timer. The communication device (100) according to appendix 1, wherein the communication device (100) switches to a state of

(Appendix 3)
The control unit (120)
a skip duration timer associated with the duration of the PDCCH skipping state;
maintaining the PDCCH skipping state when the skip period timer is running;
The communication device (100) according to appendix 2, wherein the control unit (120) stops the skip period timer based on expiration of the HARQ-RTT timer.

(Appendix 4)
When the current search space set group (SSSG) is in the PDCCH skipping state, the control unit (120) shifts to a state of monitoring the PDCCH by the CG-based switching process in response to the expiration of the HARQ-RTT timer. The communication device (100) according to appendix 2.

(Appendix 5)
The communication device (100) according to appendix 4, wherein the control unit (120) switches to a predetermined SSSG as the SSSG for monitoring the PDCCH in response to expiration of the HARQ-RTT timer.

(Appendix 6)
The control unit (120) switches to the default SSSG as the predetermined SSSG in response to expiration of the HARQ-RTT timer when a default SSSG is set. Communication according to appendix 5 A device (100).

(Appendix 7)
The control unit (120) switches to the predetermined SSSG set by the base station (200) upon expiration of the HARQ-RTT timer when the default SSSG is not set. A communication device (100).

(Appendix 8)
further comprising a receiving unit (112) for receiving switching control information for controlling the CG-induced switching process,
8. The communication device (100) according to any one of appendices 1 to 7, wherein the control unit (120) controls the CG-induced switching process based on the switching control information.

(Appendix 9)
The switching control information is information regarding whether to enable the CG-based switching process,
The communication device (100) according to appendix 8, wherein the control unit (120) performs the CG-induced switching process based on the switching control information indicating that the CG-induced switching process is enabled.

(Appendix 10)
A base station (200) that performs wireless communication with a communication device (100),
a receiving unit (212) that receives uplink data by CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station (200), from the communication device (100);
Physical downlink control channel (PDCCH) in response to expiration of the HARQ-round trip time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of the uplink data transmitted in the CG transmission PDCCH monitoring state related to monitoring a transmission unit (211) for transmitting switching control information for controlling switching processing caused by CG switching to the communication device (100);
The HARQ-RTT timer is a timer that defines the minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200).

(Appendix 11)
A communication method executed by a communication device (100) that performs wireless communication with a base station (200),
a step of performing CG transmission, which is an uplink transmission based on a configuration grant (CG) from the base station (200);
According to the CG transmission, performing a CG-induced switching process for switching a PDCCH monitoring state regarding monitoring of a physical downlink control channel (PDCCH);
In the step of performing the CG-induced switching process, in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted in the CG transmission, the CG-induced switching process and
The HARQ-RTT timer is a timer that defines a minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200).

Claims (11)

1. A communication device (100) that performs wireless communication with a base station (200),
   a transmission unit (111) that performs CG transmission, which is uplink transmission based on the configuration grant (CG) from the base station (200);
   A control unit (120) that performs CG-induced switching processing to switch the PDCCH monitoring state related to monitoring of the physical downlink control channel (PDCCH) according to the CG transmission,
   The control unit (120) performs the CG-induced switching process in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted by the CG transmission. ,
   The HARQ-RTT timer is a timer that defines a minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200). The communication device (100).
2. When the PDCCH monitoring state is a PDCCH skipping state in which the PDCCH is not monitored, the control unit (120) monitors the PDCCH by the CG-based switching process based on the expiration of the HARQ-RTT timer. The communication device (100) of claim 1, wherein the communication device (100) switches to a state of
3. The control unit (120)
   a skip duration timer associated with the duration of the PDCCH skipping state;
   maintaining the PDCCH skipping state when the skip period timer is running;
   The communication device (100) according to claim 2, wherein the controller (120) stops the skip duration timer based on expiration of the HARQ-RTT timer.
4. When the current search space set group (SSSG) is in the PDCCH skipping state, the control unit (120) shifts to a state of monitoring the PDCCH by the CG-based switching process in response to the expiration of the HARQ-RTT timer. 3. The communication device (100) of claim 2, wherein the switching.
5. The communication device (100) according to claim 4, wherein the control unit (120) switches the SSSG for monitoring the PDCCH to a predetermined SSSG in response to expiration of the HARQ-RTT timer.
6. 6. The control unit (120) according to claim 5, wherein when a default SSSG set to a default is set, the predetermined SSSG is switched to the default SSSG according to expiration of the HARQ-RTT timer. A communication device (100).
7. 7. The control unit (120) switches to the predetermined SSSG set by the base station (200) upon expiration of the HARQ-RTT timer when the default SSSG is not set. communication device (100).
8. further comprising a receiving unit (112) for receiving switching control information for controlling the CG-induced switching process,
   The communication device (100) according to Claim 1 or 2, wherein the control unit (120) controls the CG-induced switching process based on the switching control information.
9. The switching control information is information regarding whether to enable the CG-based switching process,
   The communication device (100) according to Claim 8, wherein the control unit (120) performs the CG-induced switching process based on the switching control information indicating that the CG-induced switching process is enabled.
10. A base station (200) that performs wireless communication with a communication device (100),
    a receiving unit (212) that receives uplink data by CG transmission, which is uplink transmission based on a configuration grant (CG) from the base station (200), from the communication device (100);
    Physical downlink control channel (PDCCH) in response to expiration of the HARQ-round trip time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of the uplink data transmitted in the CG transmission PDCCH monitoring state related to monitoring a transmission unit (211) for transmitting switching control information for controlling switching processing caused by CG switching to the communication device (100);
    The HARQ-RTT timer is a timer that defines the minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200).
11. A communication method executed by a communication device (100) that performs wireless communication with a base station (200),
    a step of performing CG transmission, which is an uplink transmission based on a configuration grant (CG) from the base station (200);
    According to the CG transmission, performing a CG-induced switching process for switching a PDCCH monitoring state regarding monitoring of a physical downlink control channel (PDCCH);
    In the step of performing the CG-induced switching process, in response to expiration of a HARQ-Round Trip Time (RTT) timer used for hybrid automatic repeat request (HARQ) processing of uplink data transmitted in the CG transmission, the CG-induced switching process and
    The HARQ-RTT timer is a timer that defines a minimum period until the communication device (100) receives acknowledgment information corresponding to the uplink data from the base station (200).
    

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