JP7785749B2 - Terminal device, base station device, and communication method - Google Patents

Description

The present invention relates to a terminal device, a base station device, and a communication method.
This application claims priority to Japanese Patent Application No. 2021-42015, filed on March 16, 2021, the contents of which are incorporated herein by reference.

A radio access method and radio network for cellular mobile communications (hereinafter referred to as "Long Term Evolution (LTE)" or "EUTRA: Evolved Universal Terrestrial Radio Access") is being studied by the 3rd Generation Partnership Project (3GPP). In LTE, base station devices are also called eNodeBs (evolved NodeBs), and terminal devices are also called UEs (User Equipment). LTE is a cellular communication system in which multiple areas covered by base station devices are arranged in the form of cells. A single base station device may manage multiple serving cells.

3GPP is currently studying and standardizing the next-generation standard (NR: New Radio) as a 5G communications method. NR is required to meet the requirements of three scenarios: eMBB (enhanced Mobile Broadband), mMTC (massive Machine Type Communication), and URLLC (Ultra Reliable and Low Latency Communication) within a single technology framework.

Support for NR in the frequency band from 52.6 GHz to 71 GHz is also being considered (Non-Patent Document 1). In addition to the 120 kHz subcarrier spacing, the introduction of subcarrier spacings of 480 kHz and 960 kHz is being considered.

"Revised WID: Extending current NR operation to 71GHz", RP-202925, CMCC 3GPP TSG RAN Meeting #90-e, Electronic Meeting, 7-11 December, 2020.

As the subcarrier spacing increases, the length of each slot decreases, increasing the processing load within each slot. Therefore, improvements to PDCCH (Physical Downlink Control Channel) monitoring are needed. While applying multi-slot scheduling, which allocates PDSCH and PUSCH resources for multiple slots in a single PDCCH, monitoring such PDCCHs for multiple slots rather than for each slot is being considered. Meanwhile, from the perspective of backward compatibility, it is desirable to apply single-slot scheduling, which allocates PDSCH and PUSCH resources for a single PDCCH, for the transmission and reception of system information, random access responses, etc. In situations where multi-slot scheduling and single-slot scheduling are used together, efficient processing for PDCCH monitoring is desired. One aspect of the present invention provides a terminal device, base station device, communication method, and communication method that perform efficient communications.

(1) In order to achieve the above object, one aspect of the present invention employs the following means. That is, a first aspect of the present invention is a terminal device comprising a processor and a memory for storing computer program code, the terminal device receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level, configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search area, and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot, and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates monitored in that slot. adjusting the number of PDCCH candidates monitored in the plurality of slots using a second upper limit value, wherein if a total number of PDCCH candidates adjusted based on the first upper limit value for the plurality of slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates adjusted for at least one slot to set the number of PDCCH candidates monitored in the plurality of slots; and if a total number of PDCCH candidates set based on the first upper limit value for the plurality of slots does not exceed the second upper limit value, not dropping the PDCCH candidates adjusted based on the first upper limit value and setting the number of PDCCH candidates adjusted based on the first upper limit value for the plurality of slots.

(2) Furthermore, the PDCCH candidates whose number is adjusted based on the first upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used, and the PDCCH candidates whose number is adjusted based on the second upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used and PDCCH candidates whose DCI format for multi-slot scheduling is used.

(3) A second aspect of the present invention is a base station device comprising a processor and a memory for storing computer program code, the base station device transmitting RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level, the base station device configuring PDCCH candidates for each slot to a terminal device based on the RRC signaling indicating the configuration of the search areas, and determining the number of PDCCH candidates monitored in each slot using a first upper limit value in the terminal device, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to determine the number of PDCCH candidates monitored in that slot, and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, the terminal device performs operations including: determining the number of PDCCH candidates monitored in the slot without dropping the PDCCH candidates configured for that slot; determining the number of PDCCH candidates monitored in multiple slots using a second upper limit value in the terminal device, wherein if the total number of PDCCH candidates determined based on the first upper limit value for multiple slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates determined for at least one slot to determine the number of PDCCH candidates monitored in the multiple slots; and if the total number of PDCCH candidates configured based on the first upper limit value for multiple slots does not exceed the second upper limit value, not dropping the PDCCH candidates determined based on the first upper limit value and determining the number of PDCCH candidates determined based on the first upper limit value for multiple slots.

(4) Furthermore, the number of PDCCH candidates determined based on the first upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling, and the number of PDCCH candidates determined based on the second upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling and PDCCH candidates that use a DCI format for multi-slot scheduling.

(5) A third aspect of the present invention is a communication method used in a terminal device, comprising the steps of: receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level; configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search area; and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot; and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates configured for that slot. and adjusting the number of PDCCH candidates monitored in multiple slots using a second upper limit value, wherein, if a total number of PDCCH candidates adjusted based on the first upper limit value for multiple slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates adjusted for at least one slot to set the number of PDCCH candidates monitored in the multiple slots, and if a total number of PDCCH candidates set based on the first upper limit value for multiple slots does not exceed the second upper limit value, not dropping the PDCCH candidates adjusted based on the first upper limit value and setting the number of PDCCH candidates adjusted based on the first upper limit value for multiple slots.

(6) Furthermore, the PDCCH candidates whose number is adjusted based on the first upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used, and the PDCCH candidates whose number is adjusted based on the second upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used and PDCCH candidates whose DCI format for multi-slot scheduling is used.

(7) A fourth aspect of the present invention is a communication method used in a base station device, comprising the steps of: transmitting RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level; configuring PDCCH candidates for each slot to a terminal device based on the RRC signaling indicating the configuration of the search areas; and determining the number of PDCCH candidates to be monitored in each slot using a first upper limit value in the terminal device, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to determine the number of PDCCH candidates to be monitored in that slot; and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, dropping at least some of the PDCCH candidates configured for that slot to determine the number of PDCCH candidates to be monitored in that slot. and determining the number of PDCCH candidates monitored in a slot by using a second upper limit value in the terminal device, wherein, when a total number of PDCCH candidates determined based on the first upper limit value for a plurality of slots exceeds the second upper limit value, at least a portion of the PDCCH candidates determined for at least one slot is dropped to determine the number of PDCCH candidates monitored in the plurality of slots, and when a total number of PDCCH candidates determined based on the first upper limit value for a plurality of slots does not exceed the second upper limit value, not dropping the PDCCH candidates determined based on the first upper limit value, and determining the number of PDCCH candidates determined based on the first upper limit value for a plurality of slots.

(8) Furthermore, the number of PDCCH candidates determined based on the first upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling, and the number of PDCCH candidates determined based on the second upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling and PDCCH candidates that use a DCI format for multi-slot scheduling.

According to one aspect of the present invention, efficient communication can be achieved between a terminal device and a base station device while reducing the processing load on the terminal device.

1 is a conceptual diagram of a wireless communication system according to an aspect of the present embodiment. 10 is an example showing the relationship between N ^slot _symb , subcarrier spacing setting μ, slot setting, and CP setting according to one aspect of the present embodiment. 1 is a diagram illustrating an example of a configuration of a radio frame, a subframe, and a slot according to an aspect of the present embodiment. FIG. 2 is a schematic diagram illustrating an example of a resource grid in a subframe according to an aspect of the present embodiment. 1 is a schematic block diagram showing the configuration of a terminal device 1 according to one aspect of the present embodiment. FIG. 2 is a schematic block diagram showing the configuration of a base station device 3 according to one aspect of the present embodiment. FIG. 10 is a diagram illustrating an example of the number of PDCCH candidates configured for each slot according to one aspect of this embodiment.

The following describes an embodiment of the present invention.

"A and/or B" may be a term including "A", "B", or "A and B".

A parameter or information indicating one or more values may mean that the parameter or information includes at least a parameter or information indicating the one or more values. The upper layer parameter may be a single upper layer parameter. The upper layer parameter may be an information element (IE) including multiple parameters.

Figure 1 is a conceptual diagram of a wireless communication system according to one aspect of this embodiment. In Figure 1, the wireless communication system includes terminal devices 1A to 1C and base station devices 3A to 3B. Hereinafter, terminal devices 1A to 1C will also be referred to as terminal devices 1 (UE). Hereinafter, base station devices 3A to 3B will also be referred to as base station devices 3 (gNB or eNB).

The base station device 3 may be configured to include one or both of an MCG (Master Cell Group) and an SCG (Secondary Cell Group). The MCG is a group of serving cells including at least a PCell (Primary Cell). The SCG is a group of serving cells including at least a PSCell (Primary Secondary Cell). The PCell may be a serving cell assigned based on initial connection. The MCG may be configured to include one or more SCells (Secondary Cells). The SCG may be configured to include one or more SCells. The serving cell identity is a short identifier for identifying the serving cell. The serving cell identity may be provided by higher layer parameters.

For example, base station device 3A and base station device 3B communicate with terminal device 1 using the same frequency (carrier). For example, base station device 3A and base station device 3B communicate with terminal device 1 using different frequencies (carriers). For example, base station device 3A communicates with terminal device 1 using the same frequency (carrier) as base station device 3B and a different frequency (carrier). For example, a frequency in a frequency band that requires a license is used. For example, a frequency in a frequency band that does not require a license is used.

The frame structure is explained below.

In a wireless communication system according to one aspect of this embodiment, at least Orthogonal Frequency Division Multiplex (OFDM) is used. An OFDM symbol is a time domain unit of OFDM. An OFDM symbol includes at least one or more subcarriers. The OFDM symbol may be converted into a time-continuous signal during baseband signal generation.

The subcarrier spacing (SCS) may be given by a subcarrier spacing Δf = 2 ^μ ·15 kHz. For example, the subcarrier spacing configuration μ may be set to any of 0, 1, 2, 3, 4, 5, and 6. For example, the subcarrier spacing may be any of 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, 480 kHz, and 960 kHz. For a certain BWP (BandWidth Part), the subcarrier spacing configuration μ may be given by a higher layer parameter.

In a wireless communication system according to an aspect of this embodiment, a time unit _Tc is used to express a length in the time domain. The time unit _Tc may be given by _Tc = 1/(Δf _max · N _f ). Δf _max may be the maximum subcarrier spacing supported in the wireless communication system according to an aspect of this embodiment. Δf _max may be Δf _max = 480 kHz. N _f may be N _f = 4096. The constant κ is κ = Δf _max · N _f / (Δf _ref N _f,ref ) = 64. Δf _ref may be 15 kHz. N _f,ref may be 2048.

The constant κ may be a value indicating the relationship between the reference subcarrier spacing and _Tc . The constant κ may be used for the length of the subframe. The number of slots included in the subframe may be determined based at least on the constant κ. _{Δf ref} is the reference subcarrier spacing, and N _f,ref is a value corresponding to the reference subcarrier spacing.

Downlink transmission and/or uplink transmission are composed of 10 ms frames. A frame is composed of 10 subframes. The length of a subframe is 1 ms. The frame length may be given regardless of the subcarrier spacing Δf. That is, the frame setting may be given regardless of μ. The subframe length may be given regardless of the subcarrier spacing Δf. That is, the subframe setting may be given regardless of μ.

For a certain subcarrier spacing setting μ, the number and index of slots included in a subframe may be given. For example, the first slot number n ^μ _s may be given in ascending order within the subframe in a range from 0 to N ^subframe,μ _slot −1. For a certain subcarrier spacing setting μ, the number and index of slots included in a frame may be given. For example, the second slot number n ^μ _s,f may be given in ascending order within the frame in a range from 0 to N ^frame,μ _slot −1. N ^slot _symb consecutive OFDM symbols may be included in one slot. N ^slot _symb may be given based at least on a slot configuration and/or a cyclic prefix (CP) configuration. The slot configuration may be provided by at least a higher layer parameter tdd-UL-DL-ConfigurationCommon. The CP configuration may be provided based at least on the higher layer parameter. The CP configuration may be provided based at least on dedicated RRC signaling. The first slot number and the second slot number are also referred to as slot numbers (slot indexes).

2A shows an example of the relationship between N ^slot _symb , subcarrier spacing setting μ, slot setting, and CP setting according to one aspect of the present embodiment. In FIG. 2A, when the slot setting is 0, the subcarrier spacing setting μ is 2, and the CP setting is normal CP (normal cyclic prefix), N ^slot _symb =14, N ^frame,μ _slot =40, and N ^subframe,μ _slot =4. 2B , when the slot setting is 0, the subcarrier spacing setting μ is 2, and the CP setting is extended cyclic prefix (CP), N ^slot _symb = 12, N ^frame,μ _slot = 40, and N ^subframe,μ _slot = 4. N ^slot _symb in slot setting 0 may correspond to twice the N ^slot _symb in slot setting 1.

In terminal device 1, common subcarrier spacing, slot settings, and CP settings may be performed for each cell, or different subcarrier spacing, slot settings, and CP settings may be performed for each cell. In base station device 3A and base station device 3B, common subcarrier spacing, slot settings, and CP settings may be performed, or different subcarrier spacing, slot settings, and CP settings may be performed.

Figure 3 shows an example of the configuration of a radio frame, subframe, and slot according to one aspect of this embodiment. In the example shown in Figure 3, the length of a slot is 0.5 ms, the length of a subframe is 1 ms, and the length of a radio frame is 10 ms. A slot may be a unit of resource allocation in the time domain. For example, a slot may be a unit to which one transport block is mapped. For example, a transport block may be mapped to one slot. Here, a transport block may be a unit of data transmitted within a predetermined interval (e.g., a transmission time interval (TTI)) specified by a higher layer (e.g., MAC: Medium Access Control, RRC: Radio Resource Control).

For example, the length of a slot may be determined by the number of OFDM symbols. For example, the number of OFDM symbols may be 7 or 14. The length of a slot may be determined based at least on the length of an OFDM symbol. The length of an OFDM symbol may vary based at least on the subcarrier spacing. The length of an OFDM symbol may also be determined based at least on the number of points in a Fast Fourier Transform (FFT) used to generate the OFDM symbol. The length of an OFDM symbol may also include the length of a cyclic prefix (CP) added to the OFDM symbol. Here, an OFDM symbol may also be referred to as a symbol. Furthermore, when a communication method other than OFDM is used in communication between the terminal device 1 and the base station device 3 (for example, when SC-FDMA or DFT-s-OFDM is used), the generated SC-FDMA symbols and/or DFT-s-OFDM symbols are also referred to as OFDM symbols. Furthermore, unless otherwise specified, OFDM includes SC-FDMA or DFT-s-OFDM.

For example, the slot length may be 0.0078125 ms, 0.03125 ms, 0.125 ms, 0.25 ms, 0.5 ms, or 1 ms. For example, if the subcarrier spacing is 15 kHz, the slot length may be 1 ms. For example, if the subcarrier spacing is 30 kHz, the slot length may be 0.5 ms. For example, if the subcarrier spacing is 120 kHz, the slot length may be 0.125 ms. For example, if the subcarrier spacing is 480 kHz, the slot length may be 0.03125 ms. For example, if the subcarrier spacing is 960 kHz, the slot length may be 0.0078125 ms. For example, if the slot length is 0.0078125 ms, one subframe may consist of 128 slots. For example, if the slot length is 0.03125 ms, one subframe may consist of 32 slots. For example, if the slot length is 0.125 ms, one subframe may consist of eight slots. For example, if the slot length is 0.25 ms, one subframe may consist of four slots. For example, if the slot length is 0.5 ms, one subframe may consist of two slots. For example, if the slot length is 1 ms, one subframe may consist of one slot.

Here, OFDM includes a multi-carrier communication method to which pulse shaping, PAPR reduction, out-of-band emission reduction, filtering, and/or phase processing (e.g., phase rotation) are applied. A multi-carrier communication method may also be a communication method in which a signal in which multiple subcarriers are multiplexed is generated/transmitted.

A radio frame may be given by the number of subframes. The number of subframes for a radio frame may be, for example, 10. A radio frame may be given by the number of slots.

In terminal device 1, a common radio frame configuration, subframe configuration, and slot configuration may be set for each cell, or a different radio frame configuration, subframe configuration, and slot configuration may be set for each cell. In base station device 3A and base station device 3B, a common radio frame configuration, subframe configuration, and slot configuration may be set, or different radio frame configurations, subframe configurations, and slot configurations may be set.

The following explains physical resources.

An antenna port is defined by the fact that the channel through which symbols are transmitted at one antenna port can be estimated from the channel through which other symbols are transmitted at the same antenna port. If the large-scale properties of the channel through which symbols are transmitted at one antenna port can be estimated from the channel through which symbols are transmitted at another antenna port, the two antenna ports are said to be Quasi Co-Location (QCL). The large-scale properties may include at least the long-range properties of the channel. The large-scale characteristics may include at least some or all of delay spread, Doppler spread, Doppler shift, average gain, average delay, and beam parameters (spatial Rx parameters). The first antenna port and the second antenna port being QCL with respect to the beam parameters may be a case where a receive beam assumed by the receiver for the first antenna port is the same as a receive beam assumed by the receiver for the second antenna port. The first antenna port and the second antenna port being QCL with respect to the beam parameters may be a case where a transmit beam assumed by the receiver for the first antenna port is the same as a transmit beam assumed by the receiver for the second antenna port. The terminal device 1 may assume that two antenna ports are QCL if the large-scale characteristics of the channel through which symbols are transmitted at one antenna port can be estimated from the channel through which symbols are transmitted at another antenna port. The fact that two antenna ports are QCL may mean that the two antenna ports are assumed to be QCL.

For each subcarrier spacing configuration and set of carriers, a resource grid of N ^μ _RB,x N ^RB _sc subcarriers and N ^(μ) _symb N ^subframe,μ _symb OFDM symbols is provided. ^{N μ} _RB,x may refer to the number of resource blocks provided for the subcarrier spacing configuration μ for carrier x. N ^μ _RB,x may also refer to the maximum number of resource blocks provided for the subcarrier spacing configuration μ for carrier x. Carrier x may refer to either a downlink carrier or an uplink carrier. That is, x may be "DL" or "UL." N ^μ _RB is a term that includes N ^μ _RB,DL and/or N ^μ _RB,UL . N ^RB _sc may refer to the number of subcarriers included in one resource block. At least one resource grid may be provided for each antenna port p, and/or for each subcarrier spacing setting μ, and/or for each transmission direction setting. The transmission directions include at least a downlink (DL) and an uplink (UL). Hereinafter, a parameter set including at least the antenna port p, the subcarrier spacing setting μ, and some or all of the transmission direction settings is also referred to as a first radio parameter set. That is, one resource grid may be provided for each first radio parameter set.

In the downlink, a carrier included in a serving cell is called a downlink carrier (or downlink component carrier). In the uplink, a carrier included in a serving cell is called an uplink carrier (uplink component carrier). Downlink component carriers and uplink component carriers are collectively referred to as component carriers (or carriers).

Each element in the resource grid assigned for each first radio parameter set is referred to as a resource element. A resource element is identified by a frequency domain index k _sc and a time domain index l _sym . For a given first radio parameter set, a resource element is identified by a frequency domain index k _sc and a time domain index l _sym . A resource element identified by the frequency domain index k _sc and the time domain index l _sym is also referred to as a resource element (k _sc , l _sym ). The frequency domain index k _sc indicates any value from 0 to N ^μ _RB N ^RB _sc −1. ^{N μ} _RB may be the number of resource blocks assigned for the subcarrier spacing setting μ. N ^RB _sc is the number of subcarriers included in a resource block, and N ^RB _sc =12. The frequency domain index k _sc may correspond to the subcarrier index k _sc . The time domain index l _sym may correspond to the OFDM symbol index l _sym .

FIG. 4 is a schematic diagram illustrating an example of a resource grid in a subframe according to one aspect of this embodiment. In the resource grid of FIG. 4, the horizontal axis represents a time domain index l _sym and the vertical axis represents a frequency domain index k _sc . In one subframe, the frequency domain of the resource grid includes N ^μ _RB N ^RB _sc subcarriers. In one subframe, the time domain of the resource grid may include 14·2 ^μ OFDM symbols. One resource block includes N ^RB _sc subcarriers. The time domain of the resource block may correspond to one OFDM symbol. The time domain of the resource block may correspond to 14 OFDM symbols. The time domain of the resource block may correspond to one or more slots. The time domain of the resource block may correspond to one subframe.

Figure 4 shows an example of a resource grid in one cell.

The terminal device 1 may be instructed to transmit and receive using only a subset of the resource grid. The subset of the resource grid is also referred to as a BWP, and the BWP may be given based at least on upper layer parameters and/or part or all of the DCI. The BWP is also referred to as a band part (BP: Bandwidth Part). In other words, the terminal device 1 may not be instructed to transmit and receive using the entire set of the resource grid. In other words, the terminal device 1 may be instructed to transmit and receive using some of the frequency resources within the resource grid. One BWP may be composed of multiple resource blocks in the frequency domain. One BWP may be composed of multiple contiguous resource blocks in the frequency domain. A BWP set for a downlink carrier is also referred to as a downlink BWP. A BWP set for an uplink carrier is also referred to as an uplink BWP.

One or more downlink BWPs may be configured for the terminal device 1. The terminal device 1 may attempt to receive a physical channel (e.g., PDCCH, PDSCH, SS/PBCH, etc.) in one of the one or more downlink BWPs. The one downlink BWP is also referred to as an activated downlink BWP.

One or more uplink BWPs may be configured for the terminal device 1. The terminal device 1 may attempt to transmit a physical channel (e.g., PUCCH, PUSCH, PRACH, etc.) in one of the one or more uplink BWPs. The one uplink BWP is also referred to as an activated uplink BWP.

A set of downlink BWPs may be configured for each serving cell. The set of downlink BWPs may include one or more downlink BWPs. A set of uplink BWPs may be configured for each serving cell. The set of uplink BWPs may include one or more uplink BWPs.

Higher layer parameters are parameters included in higher layer signals. The higher layer signals may be RRC (Radio Resource Control) signaling or MAC CE (Medium Access Control Control Element). Here, the higher layer signals may be RRC layer signals or MAC layer signals.

The higher layer signal may be common RRC signaling. The common RRC signaling may include at least some or all of the following features C1 to C3:
Feature C1) Mapped to the BCCH logical channel or the CCCH logical channel. Feature C2) Includes at least the radioResourceConfigCommon information element. Feature C3) Mapped to the PBCH.

The radioResourceConfigCommon information element may include information indicating a configuration commonly used in the serving cell. The configuration commonly used in the serving cell may include at least a PRACH configuration. The PRACH configuration may at least indicate one or more random access preamble indices. The PRACH configuration may at least indicate time/frequency resources for the PRACH.

The higher layer signaling may be dedicated RRC signaling, which may comprise at least some or all of the following features D1 to D2:
Feature D1) Mapped to DCCH logical channel Feature D2) Includes at least radioResourceConfigDedicated information element

The radioResourceConfigDedicated information element may include at least information indicating settings specific to the terminal device 1. The radioResourceConfigDedicated information element may include at least information indicating the settings of the BWP. The settings of the BWP may indicate at least the frequency resources of the BWP.

For example, the MIB, the first system information, and the second system information may be included in common RRC signaling. Furthermore, an upper layer message that is mapped to a DCCH logical channel and that includes at least the radioResourceConfigCommon information element may be included in common RRC signaling. Furthermore, an upper layer message that is mapped to a DCCH logical channel and that does not include the radioResourceConfigCommon information element may be included in dedicated RRC signaling. Furthermore, an upper layer message that is mapped to a DCCH logical channel and that includes at least the radioResourceConfigDedicated information element may be included in dedicated RRC signaling.

The first system information may at least indicate a time index of an SS (Synchronization Signal) block. The SS block is also referred to as an SS/PBCH block. The SS/PBCH block is also referred to as an SS/PBCH. The first system information may include at least information related to PRACH resources. The first system information may include at least information related to setting up an initial connection. The second system information may be system information other than the first system information.

The radioResourceConfigDedicated information element may include at least information related to PRACH resources. The radioResourceConfigDedicated information element may include at least information related to setting up an initial connection.

The following describes physical channels and physical signals related to various aspects of this embodiment.

An uplink physical channel may correspond to a set of resource elements carrying information generated in a higher layer. An uplink physical channel is a physical channel used in an uplink carrier. In a wireless communication system according to one aspect of the present embodiment, at least some or all of the following uplink physical channels are used:
・PUCCH (Physical Uplink Control Channel)
・PUSCH (Physical Uplink Shared Channel)
・PRACH (Physical Random Access CHannel)

PUCCH may be used to transmit uplink control information (UCI). The uplink control information includes part or all of a Hybrid Automatic Repeat request ACKnowledgement (HARQ-ACK) corresponding to a channel state information (CSI), a scheduling request (SR), a transport block (TB, MAC PDU: Medium Access Control Protocol Data Unit, DL-SCH: Downlink-Shared Channel, PDSCH: Physical Downlink Shared Channel). The uplink control information may include information not described above.

The HARQ-ACK may include at least a HARQ-ACK bit (HARQ-ACK information) corresponding to at least one transport block. The HARQ-ACK bit may indicate an ACK (acknowledgement) or a NACK (negative-acknowledgement) corresponding to one or more transport blocks. The HARQ-ACK may include at least a HARQ-ACK codebook including one or more HARQ-ACK bits. The HARQ-ACK bit corresponding to one or more transport blocks may correspond to a PDSCH including the one or more transport blocks. The HARQ-ACK bit may indicate an ACK or NACK corresponding to one Code Block Group (CBG) included in the transport block.

The scheduling request (SR) may be used at least to request PUSCH resources for the initial transmission. The scheduling request bit may be used to indicate either a positive SR or a negative SR. When the scheduling request bit indicates a positive SR, this is also referred to as "a positive SR being transmitted." A positive SR may indicate that PUSCH resources for the initial transmission are requested by the terminal device 1. A positive SR may indicate that a scheduling request is triggered by a higher layer. A positive SR may be transmitted when a scheduling request is instructed to be transmitted by a higher layer. When the scheduling request bit indicates a negative SR, this is also referred to as "a negative SR being transmitted." A negative SR may indicate that PUSCH resources for the initial transmission are not requested by the terminal device 1. A negative SR may indicate that no scheduling request is triggered by higher layers. A negative SR may be sent when no scheduling request is instructed to be sent by higher layers.

The channel state information may include at least some or all of a channel quality indicator (CQI), a precoder matrix indicator (PMI), and a rank indicator (RI). The CQI is an indicator related to the channel quality (e.g., propagation strength), the PMI is an indicator indicating the precoder, and the RI is an indicator indicating the transmission rank (or the number of transmission layers).

One or more PUCCH formats (e.g., PUCCH format 0 to PUCCH format 4) may be supported for the PUCCH. The PUCCH format may be mapped to the PUCCH and transmitted. The PUCCH format may be transmitted on the PUCCH. Transmission of a PUCCH format may also mean transmission of the PUCCH.

PUSCH is used at least to transmit transport blocks (TB, MAC PDU, UL-SCH, PUSCH). PUSCH may be used at least to transmit some or all of the transport blocks, HARQ-ACK, channel state information, and scheduling requests. PUSCH is used at least to transmit random access message 3. PUSCH may also be used to transmit information not listed above.

The PRACH is used at least to transmit a random access preamble (random access message 1). The PRACH may be used at least to indicate some or all of the following: an initial connection establishment procedure, a handover procedure, a connection re-establishment procedure, synchronization (timing adjustment) for PUSCH transmission, and a request for resources for PUSCH. The random access preamble may be used to notify the base station device 3 of an index (random access preamble index) provided by a higher layer of the terminal device 1.

In Fig. 1, the following uplink physical signals are used in uplink wireless communication: The uplink physical signals may not be used to transmit information output from higher layers, but are used by the physical layer.
・UL DMRS (UpLink Demodulation Reference Signal)
・SRS (Sounding Reference Signal)
・UL PTRS (UpLink Phase Tracking Reference Signal)

UL DMRS is related to the transmission of PUSCH and/or PUCCH. UL DMRS is multiplexed with PUSCH or PUCCH. Base station device 3 may use UL DMRS to perform propagation path correction for PUSCH or PUCCH. Hereinafter, transmitting both PUSCH and UL DMRS related to the PUSCH will be simply referred to as transmitting PUSCH. Hereinafter, transmitting both PUCCH and UL DMRS related to the PUCCH will be simply referred to as transmitting PUCCH. UL DMRS related to PUSCH is also referred to as UL DMRS for PUSCH. UL DMRS related to PUCCH is also referred to as UL DMRS for PUCCH.

The SRS may not be related to the transmission of the PUSCH or PUCCH. The base station device 3 may use the SRS to measure the channel condition. The SRS may be transmitted at the end of a subframe in an uplink slot or a predetermined number of OFDM symbols from the end.

The UL PTRS may be a reference signal used at least for phase tracking. The UL PTRS may be associated with a UL DMRS group including at least antenna ports used for one or more UL DMRSs. The association of the UL PTRS with the UL DMRS group may be such that the antenna port of the UL PTRS and some or all of the antenna ports included in the UL DMRS group are at least QCL. The UL DMRS group may be identified based at least on the antenna port with the smallest index in the UL DMRS included in the UL DMRS group. The UL PTRS may be mapped to the antenna port with the smallest index among one or more antenna ports to which a codeword is mapped. When a codeword is mapped to at least the first layer and the second layer, the UL PTRS may be mapped to the first layer. The UL PTRS may not be mapped to the second layer. The index of the antenna port to which the UL PTRS is mapped may be given based at least on the downlink control information.

In addition, uplink physical signals not described above may also be used.

1, the following downlink physical channels are used in downlink wireless communication from the base station device 3 to the terminal device 1. The downlink physical channels are used by the physical layer to transmit information output from higher layers.
・PBCH (Physical Broadcast Channel)
・PDCCH (Physical Downlink Control Channel)
・PDSCH (Physical Downlink Shared Channel)

The PBCH is used at least to transmit the Master Information Block (MIB, BCH, Broadcast Channel). The PBCH may be transmitted based on a predetermined transmission interval. The PBCH may be transmitted at intervals of 80 ms. The PBCH may be transmitted at intervals of 160 ms. The content of the information contained in the PBCH may be updated every 80 ms. Some or all of the information contained in the PBCH may be updated every 160 ms. The PBCH may be composed of 288 subcarriers. The PBCH may be composed of 2, 3, or 4 OFDM symbols. The MIB may include information related to an identifier (index) of the synchronization signal. The MIB may include information indicating at least a portion of the slot number, subframe number, and/or radio frame number in which the PBCH is transmitted.

The PDCCH is used at least for transmitting downlink control information (DCI). The PDCCH may be transmitted including at least the downlink control information. The PDCCH may include the downlink control information. The downlink control information is also referred to as a DCI format. The downlink control information may include at least either a downlink grant (DL grant) or an uplink grant (UL grant). The DCI format used for scheduling the PDSCH is also referred to as a downlink DCI format. The DCI format used for scheduling the PUSCH is also referred to as an uplink DCI format. The downlink grant is also referred to as a downlink assignment (DL assignment) or a downlink allocation (DL allocation). The uplink DCI format includes at least one or both of DCI format 0_0 and DCI format 0_1.

DCI format 0_0 is configured to include at least some or all of 1A to 1F.
1A) DCI Format Identifier Field
1B) Frequency Domain Resource Assignment Field
1C) Time Domain Resource Allocation Field
1D) Frequency Hopping Flag Field
1E) MCS field (Modulation and Coding Scheme field)
1F) CSI request field

The DCI format specification field may be used at least to indicate to which of one or more DCI formats the DCI format containing the DCI format specification field corresponds. The one or more DCI formats may be based at least on some or all of DCI format 1_0, DCI format 1_1, DCI format 0_0, and/or DCI format 0_1.

The frequency domain resource allocation field may be used at least to indicate the allocation of frequency resources for a PUSCH scheduled by a DCI format including the frequency domain resource allocation field. The frequency domain resource allocation field is also referred to as an FDRA (Frequency Domain Resource Allocation) field.

The time domain resource allocation field may be used at least to indicate the allocation of time resources for a PUSH scheduled by a DCI format that includes the time domain resource allocation field.

The frequency hopping flag field may be used at least to indicate whether frequency hopping is applied to a PUSH scheduled by a DCI format that includes the frequency hopping flag field.

The MCS field may be used to indicate at least a modulation scheme and/or a target coding rate for a PUSCH scheduled by a DCI format including the MCS field. The target coding rate may be a target coding rate for a transport block of the PUSCH. The size of the transport block (TBS: Transport Block Size) may be determined based at least on the target coding rate.

The CSI request field is used at least to indicate the reporting of CSI. The size of the CSI request field may be a predetermined value. The size of the CSI request field may be 0, 1, 2, or 3.

DCI format 0_1 is configured to include at least some or all of 2A to 2H.
2A) DCI format specific field 2B) Frequency domain resource allocation field 2C) Time domain resource allocation field 2D) Frequency hopping flag field 2E) MCS field 2F) CSI request field
2G) BWP field
2H) UL DAI field (Downlink Assignment Index)

The UL DAI field is used at least to indicate the transmission status of the PDSCH. If a dynamic HARQ-ACK codebook is used, the size of the UL DAI field may be 2 bits. The UL DAI field indicates the size of the HARQ-ACK codebook transmitted on the PUSCH. The UL DAI field indicates the number of HARQ-ACKs included in the HARQ-ACK codebook transmitted on the PUSCH. The UL DAI field indicates the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted on the PUSCH. The UL DAI field indicates the number of PDSCHs and SPS releases in which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted on the PUSCH.

The UL DAI field may indicate a value to which modulo arithmetic has been applied. An example in which the UL DAI field is 2 bits will be described. If the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted on the PUSCH is 0, the UL DAI field indicates "00". If the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted on the PUSCH is 1, the UL DAI field indicates "01". If the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted on the PUSCH is 2, the UL DAI field indicates "10". When the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted by the PUSCH is three, the UL DAI field indicates "11". When the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted by the PUSCH is four, the UL DAI field indicates "00". When the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted by the PUSCH is five, the UL DAI field indicates "01". When the number of PDSCHs for which the corresponding HARQ-ACK is included in the HARQ-ACK codebook transmitted by the PUSCH is six, the UL DAI field indicates "10". When the number of PDSCHs for which the corresponding HARQ-ACKs are included in the HARQ-ACK codebook transmitted on the PUSCH is 7, the UL DAI field indicates "11." In this example, a modulo operation using the value "4" is performed on the number of PDSCHs for which the corresponding HARQ-ACKs are included in the HARQ-ACK codebook transmitted on the PUSCH.

The terminal device 1 interprets the UL DAI field taking into account the total number of received PDSCHs. For example, the terminal device 1 receives four PDSCHs and receives a UL DAI field indicating "00". In this case, the terminal device 1 interprets the number of PDSCHs whose corresponding HARQ-ACKs are included in the HARQ-ACK codebook transmitted on the PUSCH indicated by the UL DAI field as four. For example, the terminal device 1 receives three PDSCHs and receives a UL DAI field indicating "00". In this case, the terminal device 1 interprets the number of PDSCHs whose corresponding HARQ-ACKs are included in the HARQ-ACK codebook transmitted on the PUSCH indicated by the UL DAI field as four, and determines that reception of one PDSCH has been missed.

The BWP field may be used to indicate the uplink BWP to which the PUSH scheduled by DCI format 0_1 is mapped.

The CSI request field is used at least to indicate the reporting of CSI. The size of the CSI request field may be based at least on the higher layer parameter ReportTriggerSize.

The downlink DCI format includes at least one or both of DCI format 1_0 and DCI format 1_1.

DCI format 1_0 is configured to include at least some or all of 3A to 3H.
3A) DCI Format Identifier Field
3B) Frequency Domain Resource Assignment Field
3C) Time Domain Resource Allocation Field
3D) Frequency hopping flag field
3E) MCS field (Modulation and Coding Scheme field)
3F) First CSI Request Field
3G) PDSCH-to-HARQ feedback timing indicator field
3H) PUCCH Resource Indicator Field

The timing indication field from the PDSCH to the HARQ feedback may be a field indicating timing K1. If the index of the slot containing the last OFDM symbol of the PDSCH is slot n, the index of the slot containing a PUCCH or PUSCH containing at least a HARQ-ACK corresponding to the transport block included in the PDSCH may be n+K1. If the index of the slot containing the last OFDM symbol of the PDSCH is slot n, the index of the slot containing the first OFDM symbol of the PUCCH or the first OFDM symbol of the PUSCH containing at least a HARQ-ACK corresponding to the transport block included in the PDSCH may be n+K1.

Hereinafter, the PDSCH-to-HARQ feedback timing indicator field (PDSCH-to-HARQ_feedback timing indicator field) may be referred to as the HARQ indication field.

The PUCCH resource indication field may be a field indicating the index of one or more PUCCH resources included in the PUCCH resource set.

DCI format 1_1 is configured to include at least some or all of 4A to 4J.
4A) DCI Format Identifier Field
4B) Frequency Domain Resource Assignment Field
4C) Time Domain Resource Allocation Field
4D) Frequency Hopping Flag Field
4E) MCS field (Modulation and Coding Scheme field)
4F) First CSI Request Field
4G) PDSCH-to-HARQ feedback timing indicator field
4H) PUCCH Resource Indicator Field
4J) BWP field

The BWP field may be used to indicate the downlink BWP to which the PDSCH scheduled by DCI format 1_1 is mapped.

DCI format 2_0 may be configured to include at least one or more slot format indicators (SFIs).

The downlink control information may include a slot format indicator (SFI). A pattern indicating whether each subframe (slot) among multiple subframes (slots) is an uplink subframe (slot), a downlink subframe (slot), or a flexible subframe (slot) may be transmitted and received using the downlink control information. The terminal device 1 may determine that a subframe (slot) not indicated by the received SFI is a flexible subframe (slot). If PUSCH transmission is scheduled for a flexible subframe (slot) by an UL grant, the terminal device 1 processes the flexible subframe (slot) as an uplink subframe (slot). If PUSCH transmission is not scheduled for a flexible subframe (slot) by an UL grant, the terminal device 1 monitors PDCCH candidates in the flexible subframe (slot) and performs processing to detect a DL assignment. When reception of the PDSCH is scheduled by a DL assignment in a flexible subframe (slot), the terminal device 1 processes the flexible subframe (slot) as a downlink subframe (slot).

For example, downlink control information including a downlink grant or an uplink grant is transmitted and received on the PDCCH, including a C-RNTI (Cell-Radio Network Temporary Identifier).

In the downlink DCI format, DCI format 1_0 may use a first format (first type downlink DCI format) that includes scheduling information for one PDSCH, or a second format (second type downlink DCI format) that includes scheduling information for multiple (e.g., two) PDSCHs. In the downlink DCI format, DCI format 1_1 may use a first format that includes scheduling information for one PDSCH, or a second format that includes scheduling information for multiple (e.g., two) PDSCHs. For example, the first format includes one frequency domain resource allocation field, one time domain resource allocation field, and one MCS field. For example, the second format includes multiple (e.g., two) frequency domain resource allocation fields, multiple (e.g., two) time domain resource allocation fields, and multiple (e.g., two) MCS fields.

In various aspects of this embodiment, unless otherwise specified, the number of resource blocks refers to the number of resource blocks in the frequency domain.

A downlink grant may be used at least for scheduling one PDSCH in one serving cell. A downlink grant may be used at least for scheduling multiple PDSCHs in one serving cell. A downlink grant may be used at least for scheduling multiple PDSCHs in multiple serving cells. A downlink grant may be used at least for scheduling a PDSCH in the same slot as the slot in which the downlink grant is transmitted. A downlink grant may be used for scheduling a PDSCH in a slot different from the slot in which the downlink grant is transmitted. An uplink grant may be used at least for scheduling one PUSCH in one serving cell. An uplink grant may be used at least for scheduling multiple PUSCHs in one serving cell. An uplink grant may be used at least for scheduling multiple PUSCHs in multiple serving cells.

Note that various DCI formats may further include fields other than those described above. They may include a field indicating the cumulative number of transmitted PDCCHs (C-DAI: Counter Downlink Assignment Index field). They may also include a field indicating the total number of transmitted PDCCHs (T-DAI: Total Downlink Assignment Index field).

The value of K1 (information or parameter indicated by the timing indication field from PDSCH to HARQ feedback) indicated by the DCI format included in the PDCCH may be, for example, a value among {0, 1, 2,..., 15}. For example, the PDSCH scheduled by this DCI format is transmitted by the base station device 3 in slot n and received by the terminal device 1. The terminal device 1 may transmit (report) HARQ-ACK information corresponding to the PDSCH via the PUCCH or PUSCH in slot n+K1.

The HARQ-ACK bits (HARQ-ACK information) corresponding to the transport blocks transmitted and received in the downlink frequency band (frequency spectrum, carrier, component carrier) of base station device 3 are transmitted and received in the uplink frequency band (frequency spectrum, carrier, component carrier) of base station device 3 in the manner described above based on at least one of the various fields described above (PDSCH-to-HARQ feedback timing indicator field, HARQ indication field, PUCCH resource indication field, C-DAI field, T-DAI field, UL DAI field) contained in the DCI format.

One physical channel may be mapped to one serving cell. One physical channel may be mapped to one BWP configured on one carrier included in one serving cell.

The terminal device 1 may be configured with one or more control resource sets (CORESET: CONTrolREsourceSET). The terminal device 1 monitors the PDCCH in one or more control resource sets. Here, monitoring the PDCCH in one or more control resource sets may include monitoring one or more PDCCHs corresponding to each of the one or more control resource sets. Note that the PDCCH may include one or more PDCCH candidates and/or sets of PDCCH candidates. Furthermore, monitoring the PDCCH may include monitoring and detecting the PDCCH and/or the DCI format transmitted via the PDCCH.

The control resource set may be a time-frequency region to which one or more PDCCHs may be mapped. The control resource set may also be a region in which the terminal device 1 monitors the PDCCHs. The control resource set may be composed of contiguous resources (localized resources). The control resource set may also be composed of discontinuous resources (distributed resources).

In the frequency domain, the unit of mapping of the control resource set may be a resource block. For example, in the frequency domain, the unit of mapping of the control resource set may be six resource blocks. In the time domain, the unit of mapping of the control resource set may be an OFDM symbol. For example, in the time domain, the unit of mapping of the control resource set may be one OFDM symbol.

The mapping of the control resource set to resource blocks may be based at least on higher layer parameters, which may include a bitmap for a group of resource blocks (RBG), which may be given by six consecutive resource blocks.

The number of OFDM symbols constituting the control resource set may be determined based at least on higher layer parameters. For example, the starting positions of the OFDM symbols constituting the control resource set are notified from the base station device 3 to the terminal device 1 using higher layer signaling. For example, the ending positions of the OFDM symbols constituting the control resource set are notified from the base station device 3 to the terminal device 1 using higher layer signaling.

A certain control resource set may be a common control resource set. The common control resource set may be a control resource set configured in common for multiple terminal devices 1. The common control resource set may be assigned based on at least some or all of the MIB, the first system information, the second system information, the common RRC signaling, and the cell ID. For example, the time resources and/or frequency resources of the control resource set configured to monitor the PDCCH used for scheduling the first system information may be assigned based at least on the MIB.

The control resource set configured in the MIB is also referred to as CORESET #0. CORESET #0 may be the control resource set with index #0.

A control resource set may be a dedicated control resource set. The dedicated control resource set may be a control resource set configured to be used exclusively for the terminal device 1. The dedicated control resource set may be assigned based on at least some or all of the dedicated RRC signaling and the value of the C-RNTI. Multiple control resource sets may be configured in the terminal device 1, and an index (control resource set index) may be assigned to each control resource set. One or more control channel elements (CCEs) may be configured within the control resource set, and an index (CCE index) may be assigned to each CCE.

A CCE may be configured to include one or more groups of REGs (Resource Element Groups). A group of REGs is also called a REG bundle. The number of REGs constituting one REG group is called the bundle size. For example, the REG bundle size may be 1, 2, 3, or 6. In interleaved mapping, an interleaver may be applied on a REG bundle basis. The terminal device 1 may assume that the precoders applied to REs within a REG group are the same. The terminal device 1 can perform channel estimation by assuming that the precoders applied to REs within a REG group are the same. On the other hand, the terminal device 1 may assume that the precoders applied to REs between REG groups are not the same. In other words, the terminal device 1 does not need to assume that the precoders applied to the REs between the groups of REGs are the same. "Between the groups of REGs" may be rephrased as "between two different groups of REGs." The terminal device 1 can perform channel estimation assuming that the precoders applied to the REs between the groups of REGs are not the same.

An REG may be composed of one OFDM symbol of one PRB. In other words, an REG may be composed of 12 consecutive REs in the frequency domain. Some of the REs constituting an REG may be REs to which downlink control information is not mapped. An REG may be composed of REs to which downlink control information is not mapped, or may be composed of REs to which downlink control information is not mapped. REs to which downlink control information is not mapped may be REs to which a reference signal is mapped, REs to which a channel other than a control channel is mapped, or REs to which a control channel is not assumed to be mapped by the terminal device 1.

A CCE may be composed of six REGs. A CCE may be composed of REGs that are contiguously mapped (such mapping may be referred to as localized mapping) (such mapping may be referred to as non-interleaved CCE-to-REG mapping) (such mapping may be referred to as non-interleaved mapping). Note that all REGs that constitute a CCE do not necessarily have to be contiguous in the frequency domain. For example, if all of the multiple resource blocks that constitute a control resource set are not contiguous in the frequency domain, even if the numbers assigned to the REGs are contiguous, the resource blocks that constitute each REG with consecutive numbers are not contiguous in the frequency domain. If a control resource set is composed of multiple OFDM symbols and multiple REGs that constitute one CCE are arranged across multiple time intervals (OFDM symbols), a CCE may be composed of a group of REGs that are contiguous.

A CCE may be composed of REGs that are mapped discontinuously (such mapping may be referred to as distributed mapping) (such mapping may be referred to as interleaved CCE-to-REG mapping) (such mapping may be referred to as interleaved mapping). REGs that constitute a CCE may be mapped discontinuously to time-frequency domain resources using an interleaver. When a control resource set is composed of multiple OFDM symbols and multiple REGs that constitute one CCE are arranged across multiple time intervals (OFDM symbols), a CCE may be composed of REGs that are mixed and mapped discontinuously. A CCE may be composed of REGs that are mapped in a distributed manner in units of multiple groups of REGs. A CCE may be composed of REGs that are mapped in a distributed manner in units of multiple groups of REGs.

The set of PDCCH candidates monitored by the terminal device 1 is defined in terms of a search space. In other words, the set of PDCCH candidates monitored by the terminal device 1 is given by the search space.

The search space may be configured to include one or more PDCCH candidates of one or more aggregation levels. The aggregation level of a PDCCH candidate may indicate the number of CCEs that make up the PDCCH. A PDCCH candidate may be mapped to one or more CCEs.

The number of CCEs constituting a PDCCH candidate is also referred to as the aggregation level (AL). When one PDCCH candidate is composed of an aggregation of multiple CCEs, one PDCCH candidate is composed of multiple CCEs with consecutive CCE numbers. A set of PDCCH candidates with aggregation level AL _X is also referred to as the search space for aggregation level AL _X. That is, the search space for aggregation level AL _X may be composed of one or more PDCCH candidates with aggregation level AL _X. Furthermore, a search space may include PDCCH candidates of multiple aggregation levels. For example, a CSS may include PDCCH candidates of multiple aggregation levels. For example, a USS may include PDCCH candidates of multiple aggregation levels. The set of aggregation levels of PDCCH candidates included in a CSS and the set of aggregation levels of PDCCH candidates included in a USS may be specified/configured, respectively.

The terminal device 1 may monitor at least one or more search spaces in slots where DRX (Discontinuous Reception) is not set. DRX may be provided based at least on higher layer parameters. The terminal device 1 may monitor at least one or more search space sets in slots where DRX is not set. Multiple search space sets may be configured in the terminal device 1. An index (search space set index) may be assigned to each search space set.

A search area set may be configured to include at least one or more search areas. Each search area may be assigned an index (search area index). A search area set may be configured with one or more search areas corresponding to one or more aggregation levels.

Each search area set may be associated with at least one control resource set. Each search area set may be included in one control resource set. Each search area set may be given an index of the control resource set associated with that search area set.

Search spaces may be of two types: CSS (Common Search Space) and USS (UE-specific Search Space). CSS may be a search space set in common for multiple terminal devices 1. USS may be a search space including settings used exclusively for individual terminal devices 1. CSS may be determined based at least on a synchronization signal, MIB, first system information, second system information, common RRC signaling, dedicated RRC signaling, cell ID, etc. USS may be determined at least on the value of dedicated RRC signaling and/or C-RNTI. CSS may be a search space set in resources (control resource elements) common to multiple terminal devices 1. USS may be a search space set in resources (control resource elements) for each individual terminal device 1.

The CSS may use a Type 0 PDCCH CSS for a DCI format scrambled by the SI-RNTI used to transmit system information in the primary cell, and a Type 1 PDCCH CSS for a DCI format scrambled by the RA-RNTI and TC-RNTI used for initial access. The CSS may use a Type 1 PDCCH CSS for a DCI format scrambled by the CC-RNTI used for unlicensed access. The terminal device 1 can monitor PDCCH candidates in these search areas. The DCI format scrambled by a specified RNTI may be a DCI format to which a CRC (Cyclic Redundancy Check) scrambled by a specified RNTI is added.

The information related to the reception of the PDCCH may include information related to an ID indicating the destination of the PDCCH. The ID indicating the destination of the PDCCH may be an ID used for scrambling the CRC bits added to the PDCCH. The ID indicating the destination of the PDCCH is also referred to as an RNTI (Radio Network Temporary Identifier). The information related to the reception of the PDCCH may include information related to an ID used for scrambling the CRC bits added to the PDCCH. The terminal device 1 can attempt to receive the PDCCH based at least on the information related to the ID included in the PBCH.

RNTI may include SI-RNTI (System Information - RNTI), P-RNTI (Paging - RNTI), C-RNTI (Common - RNTI), Temporary C-RNTI (TC-RNTI), RA-RNTI (Random Access - RNTI), CC-RNTI (Common Control - RNTI), and INT-RNTI (Interruption - RNTI). SI-RNTI is used at least for scheduling PDSCHs transmitted containing system information. P-RNTI is used at least for scheduling PDSCHs transmitted containing information such as paging information and/or system information change notifications. The C-RNTI is used at least for scheduling user data for the RRC-connected terminal device 1. The Temporary C-RNTI is used at least for scheduling the random access message 4. The Temporary C-RNTI is used at least for scheduling the PDSCH including data mapped to the CCCH in the logical channel. The RA-RNTI is used at least for scheduling the random access message 2. The CC-RNTI is used at least for transmitting and receiving control information for unlicensed access. The INT-RNTI is used at least for indicating pre-emption in the downlink.

In addition, the PDCCH and/or DCI included in the CSS may not include a CIF (Carrier Indicator Field) indicating which serving cell (or which component carrier) the PDCCH/DCI is scheduling the PDSCH or PUSCH for.

In addition, when carrier aggregation (CA), which aggregates multiple serving cells and/or multiple component carriers to perform communication (transmission and/or reception), is configured for the terminal device 1, the PDCCH and/or DCI included in the USS for a specified serving cell (specified component carrier) may include a CIF indicating which serving cell and/or which component carrier the PDCCH/DCI is scheduling the PDSCH or PUSCH for.

In addition, when communication is performed using one serving cell and/or one component carrier for terminal device 1, the PDCCH and/or DCI included in the USS does not need to include a CIF indicating which serving cell and/or which component carrier the PDCCH/DCI is scheduling the PDSCH or PUSCH for.

A common control resource set may include a CSS. A common control resource set may include both a CSS and a USS. A dedicated control resource set may include a USS. A dedicated control resource set may include a CSS.

The physical resources of the search area are composed of control channel units (CCEs). A CCE is composed of a predetermined number of resource element groups (REGs). For example, a CCE may be composed of six REGs. A REG may be composed of one OFDM symbol of one PRB (Physical Resource Block). In other words, a REG may be composed of 12 resource elements (REs). A PRB is also simply referred to as an RB (Resource Block).

In other words, the terminal device 1 can detect the PDCCH and/or DCI for the terminal device 1 by blindly detecting the PDCCH candidates included in the search space within the control resource set.

The number of blind detections for one control resource set in one serving cell and/or one component carrier may be determined based on the type of search space for the PDCCH included in the control resource set, the type of aggregation level, and the number of PDCCH candidates. The number of PDCCH candidates for each aggregation level may be configured for the terminal device 1 as a search space set. Here, the type of search space may include at least one of CSS and/or USS and/or UGSS (UE Group SS) and/or GCSS (Group CSS). The type of aggregation level indicates the maximum aggregation level supported for the CCEs that make up the search space, and may be specified/set from at least one of {1, 2, 4, 8, ..., X} (X is a predetermined value). The number of PDCCH candidates may indicate the number of PDCCH candidates for a certain aggregation level. In other words, the number of PDCCH candidates may be specified/set for each of multiple aggregation levels. The UGSS may be a search space commonly assigned to one or more terminal devices 1. The GCSS may be a search space to which DCI including parameters related to the CSS is mapped for one or more terminal devices 1. The aggregation level indicates an aggregation level for a predetermined number of CCEs, and is related to the total number of CCEs that constitute one PDCCH and/or search space.

The size of the aggregation level may be associated with the coverage corresponding to the PDCCH and/or search area or the size of the DCI included in the PDCCH and/or search area (DCI format size, payload size). The type of DCI format to be monitored may be configured for each search area.

Note that if a start position (start symbol) of a PDCCH symbol is configured for one control resource set and if more than one PDCCH in the control resource set can be detected within a specified period, the type of search space for the PDCCH included in the control resource set, the type of aggregation level, and the number of PDCCH candidates may be configured for the time region corresponding to each start symbol. If there are more than one start position (start symbol) of the PDCCH symbol for one control resource set, that is, if there are multiple timings for blind detection (monitoring) of the PDCCH within a specified period, the type of search space for the PDCCH included in the control resource set, the type of aggregation level, and the number of PDCCH candidates may be configured for the time region corresponding to each start symbol. The type of search space, the type of aggregation level, and the number of PDCCH candidates for the PDCCH included in the control resource set may be configured for each control resource set, or may be provided/configured via DCI and/or higher layer signaling (RRC signaling), or may be predefined/configured in advance by a specification. The number of PDCCH candidates may be the number of PDCCH candidates in a predetermined period. The predetermined period may be 1 millisecond. The predetermined period may be 1 microsecond. The predetermined period may be a period of one slot. The predetermined period may be a period of one OFDM symbol.

In addition, as a way of indicating the number of PDCCCH candidates, the number to be reduced from a predetermined number of PDCCCH candidates may be specified/set for each aggregation level.

The terminal device 1 may transmit/notify the base station device 3 of capability information related to blind detection. The terminal device 1 may transmit/notify the base station device 3 of the number of PDCCH candidates that can be processed in one subframe as capability information related to the PDCCH. The terminal device 1 may transmit/notify the base station device 3 of capability information related to blind detection when more than a predetermined number of control resource sets can be configured for one or more serving cells/component carriers. The terminal device 1 may transmit/notify the base station device 3 of the number of PDCCH candidates that can be processed in one slot as capability information related to the PDCCH. The terminal device 1 may transmit/notify the base station device 3 of the number of PDCCH candidates that can be processed in multiple slots (e.g., four slots, eight slots) as capability information related to the PDCCH. The terminal device 1 may transmit/notify the base station device 3 of the number of PDCCH candidates that can be processed in one slot (upper limit value) when multi-slot scheduling and single-slot scheduling are used together as capability information related to the PDCCH. The terminal device 1 may transmit/notify the base station device 3, as capability information related to the PDCCH, of the number (upper limit) of PDCCH candidates that can be processed in one slot when only single-slot scheduling is applied without multi-slot scheduling, and the number (upper limit) of PDCCH candidates that can be processed in one slot when multi-slot scheduling and single-slot scheduling are used in combination, in separate information (information elements). The terminal device 1 may transmit/notify the base station device 3, as capability information related to the PDCCH, of the number (upper limit) of PDCCH candidates that can be processed in one slot with respect to the DCI format for single-slot scheduling (first upper limit). The terminal device 1 may transmit/notify the base station device 3, as capability information related to the PDCCH, of the number (upper limit) of PDCCH candidates that can be processed in one slot with respect to the DCI format for single-slot scheduling when multi-slot scheduling and single-slot scheduling are used in combination (first upper limit). The terminal device 1 may transmit/notify the base station device 3 of the number (upper limit) of PDCCH candidates that can be processed in one slot (first upper limit) for the DCI format for single slot scheduling and the DCI format for multi-slot scheduling when multi-slot scheduling and single slot scheduling are used together, as capability information related to the PDCCH. The terminal device 1 may transmit/notify the base station device 3 of capability information related to blind detection of the PDCCH for each subcarrier interval.

The terminal device 1 may transmit/notify capability information related to blind detection to the base station device 3 if more than a specified number of control resource sets can be configured for a specified period of one or more serving cells/component carriers.

The capability information related to blind detection may include information indicating the maximum number of blind detections in a specified period. The capability information related to blind detection may also include information indicating that PDCCH candidates can be reduced. The capability information related to blind detection may also include information indicating the maximum number of control resource sets for which blind detection is possible in a specified period. The maximum number of control resource sets and the maximum number of serving cells and/or component carriers for which PDCCH monitoring is possible may each be set as individual parameters or as a common parameter. The capability information related to blind detection may also include information indicating the maximum number of control resource sets for which blind detection can be performed simultaneously in a specified period.

If the terminal device 1 does not support the capability to detect (blind detection) more than a predetermined number of control resource sets in a predetermined period, it does not need to transmit/notify capability information related to the blind detection. If the base station device 3 does not receive capability information related to the blind detection, it may configure the control resource sets so as not to exceed the predetermined number for blind detection and transmit a PDCCH.

The settings for the control resource set include a parameter indicating an index (ControlResourceSetId) that identifies the control resource set. The settings for the control resource set may also include a parameter indicating the frequency resource domain of the control resource set (the number of resource blocks that make up the control resource set). The settings for the control resource set may also include a parameter indicating the type of mapping from CCE to REG. The settings for the control resource set may also include the REG bundle size. RRC signaling may be used to send and receive messages indicating the settings for the control resource set. SIB may be used to send and receive messages indicating the settings for the control resource set. MIB may be used to send and receive messages indicating the settings for the control resource set.

The search area configuration includes a parameter indicating an index (search area index) that identifies the search area. The search area configuration includes a parameter indicating the index of the control resource set in which the search area is located. The search area configuration may include parameters indicating the periodicity and offset (relative slot position in which the search area is located) of the slot in which the search area is located. The search area configuration may include a parameter indicating the number of slots in which the search area is consecutively located. The search area configuration may include a parameter indicating the OFDM symbols in the slot in which PDCCH candidates are monitored. The search area configuration may include a parameter indicating the number of PDCCH candidates to be monitored per CCE aggregation level. The search area configuration may include a parameter indicating the DCI format in which monitoring is performed. The search area configuration may include a parameter indicating the type of search area (CSS or USS). RRC signaling may be used to transmit and receive messages indicating the search area configuration. SIB may be used to transmit and receive messages indicating the search area configuration. MIB may be used to transmit and receive messages indicating the search area configuration.

As a parameter indicating the DCI format for monitoring, a downlink grant including scheduling information for multiple PDSCHs may be included in the search area configuration. As a parameter indicating the DCI format for monitoring, a downlink grant including scheduling information for one PDSCH for one slot (DCI format for single-slot scheduling) may be included in the search area configuration. As a parameter indicating the DCI format for monitoring, a downlink grant including scheduling information for multiple PDSCHs for multiple slots (DCI format for multi-slot scheduling) may be included in the search area configuration. As a parameter indicating the DCI format for monitoring, a downlink grant including scheduling information for PDSCHs for multiple cells may be included in the search area configuration. As a parameter indicating the DCI format for monitoring, a downlink grant including scheduling information for multiple PDSCHs for multiple cells may be included in the search area configuration. Here, the multiple cells may be the cell in which the search area is set and the cell to which cross-carrier scheduling is applied from the cell in which the search area is set.

Base station device 3 sets a search area for terminal device 1. Base station device 3 transmits setting information regarding the search area to terminal device 1. Terminal device 1 receives setting information regarding the search area from base station device 3. Terminal device 1 sets a search area based on the information received from base station device 3.

The PDSCH is used at least for transmitting/receiving transport blocks. The PDSCH may also be used at least for transmitting/receiving random access message 2 (random access response). The PDSCH may also be used at least for transmitting/receiving system information including parameters used for initial access.

In Figure 1, the following downlink physical signals are used in downlink wireless communication: The downlink physical signals may not be used to transmit information output from higher layers, but are used by the physical layer.
・Synchronization signal (SS)
・DL DMRS (DownLink DeModulation Reference Signal)
・CSI-RS (Channel State Information-Reference Signal)
・DL PTRS (DownLink Phase Tracking Reference Signal)

The synchronization signal is used by the terminal device 1 to synchronize the frequency domain and/or time domain of the downlink. The synchronization signal includes a PSS (Primary Synchronization Signal) and an SSS (Secondary Synchronization Signal).

An SS block (SS/PBCH block) is composed of at least some or all of the PSS, SSS, and PBCH.

DL DMRS is related to the transmission of PBCH, PDCCH, and/or PDSCH. DL DMRS is multiplexed onto PBCH, PDCCH, and/or PDSCH. The terminal device 1 may use the DL DMRS corresponding to the PBCH, PDCCH, or PDSCH to perform propagation path correction for the PBCH, PDCCH, or PDSCH. The terminal device 1 may determine that the base station device 3 is transmitting a signal based on detection of the DL DMRS.

The CSI-RS may be a signal used at least to calculate channel state information. The CSI-RS pattern assumed by the terminal device 1 may be given at least by higher layer parameters.

The PTRS may be a signal used at least for phase noise compensation. The PTRS pattern assumed by the terminal device 1 may be based at least on higher layer parameters and/or DCI.

A DL PTRS may be associated with a DL DMRS group that includes at least the antenna ports used for one or more DL DMRSs.

In addition, downlink physical signals not described above may also be used.

Downlink physical channels and downlink physical signals are also referred to as downlink signals. Uplink physical channels and uplink physical signals are also referred to as uplink signals. Downlink signals and uplink signals are collectively referred to as physical signals. Downlink signals and uplink signals are collectively referred to as signals. Downlink physical channels and uplink physical channels are collectively referred to as physical channels. Downlink physical signals and uplink physical signals are collectively referred to as physical signals.

BCH (Broadcast Channel), UL-SCH (Uplink-Shared Channel), and DL-SCH (Downlink-Shared Channel) are transport channels. Channels used in the Medium Access Control (MAC) layer are called transport channels. The unit of transport channel used in the MAC layer is also called a transport block (TB) or MAC PDU. In the MAC layer, HARQ (Hybrid Automatic Repeat reQuest) control is performed for each transport block. A transport block is the unit of data that the MAC layer delivers to the physical layer. In the physical layer, transport blocks are mapped to codewords, and modulation processing is performed for each codeword.

The base station device 3 and the terminal device 1 exchange (transmit and receive) higher layer signals at higher layers. For example, the base station device 3 and the terminal device 1 may transmit and receive RRC signaling (RRC message; RRC information) at the Radio Resource Control (RRC) layer. The base station device 3 and the terminal device 1 may also transmit and receive MAC Control Elements (CEs) at the MAC layer. Here, the RRC signaling and/or the MAC CE are also referred to as higher layer signaling.

PUSCH and PDSCH may be used at least to transmit RRC signaling and/or MAC CE. Here, the RRC signaling transmitted by the base station device 3 on the PDSCH may be signaling common to multiple terminal devices 1 in the serving cell. Signaling common to multiple terminal devices 1 in the serving cell is also referred to as common RRC signaling. The RRC signaling transmitted by the base station device 3 on the PDSCH may be signaling dedicated to a certain terminal device 1 (also referred to as dedicated signaling or UE-specific signaling). Signaling dedicated to a terminal device 1 is also referred to as dedicated RRC signaling. Upper layer parameters specific to the serving cell may be transmitted/received using signaling common to multiple terminal devices 1 in the serving cell or signaling dedicated to a certain terminal device 1. UE-specific higher layer parameters may be transmitted/received using signaling dedicated to a certain terminal device 1.

The BCCH (Broadcast Control Channel), CCCH (Common Control Channel), and DCCH (Dedicated Control Channel) are logical channels. For example, the BCCH is an upper layer channel used to transmit/receive MIBs. The CCCH (Common Control Channel) is an upper layer channel used to transmit/receive information common to multiple terminal devices 1. Here, the CCCH may be used, for example, for terminal devices 1 that are not RRC connected. The DCCH (Dedicated Control Channel) is an upper layer channel used at least to transmit/receive control information dedicated to the terminal device 1. Here, the DCCH may be used, for example, for a terminal device 1 that is RRC connected.

The BCCH in the logical channel may be mapped to the BCH, DL-SCH, or UL-SCH in the transport channel. The CCCH in the logical channel may be mapped to the DL-SCH or UL-SCH in the transport channel. The DCCH in the logical channel may be mapped to the DL-SCH or UL-SCH in the transport channel.

The UL-SCH in the transport channel may be mapped to the PUSCH in the physical channel. The DL-SCH in the transport channel may be mapped to the PDSCH in the physical channel. The BCH in the transport channel may be mapped to the PBCH in the physical channel.

Below, an example configuration of a terminal device 1 relating to one aspect of this embodiment is described.

Figure 5 is a schematic block diagram showing the configuration of a terminal device 1 according to one aspect of this embodiment. As shown in the figure, the terminal device 1 includes a radio transceiver unit 10 and an upper layer processing unit 14. The radio transceiver unit 10 includes at least an antenna unit 11, an RF (Radio Frequency) unit 12, and some or all of a baseband unit 13. The upper layer processing unit 14 includes at least a medium access control layer processing unit 15 and some or all of a radio resource control layer processing unit 16. The radio transceiver unit 10 is also referred to as a transmitter, receiver, or physical layer processing unit.

The physical layer processing unit includes a decoding unit. The receiving unit (also referred to as the receiving processing unit) of the terminal device 1 receives the PDCCH. The decoding unit of the terminal device 1 decodes the received PDCCH. More specifically, the decoding unit of the terminal device 1 performs blind decoding processing on the received signal of the resource corresponding to the USS PDCCH candidate. The decoding unit of the terminal device 1 performs blind decoding processing on the received signal of the resource corresponding to the CSS PDCCH candidate. The receiving processing unit of the terminal device 1 monitors the PDCCH candidates within the control resource set. The receiving processing unit of the terminal device 1 monitors the PDCCH candidates within the control resource set. The decoding unit of the terminal device 1 performs different blind decoding processing for each DCI format of a different size.

The transmitter (also referred to as the transmission processing unit) of terminal device 1 transmits a HARQ-ACK. The transmission processing unit of terminal device 1 transmits a HARQ-ACK for the PDSCH. The transmission processing unit of terminal device 1 transmits a HARQ-ACK in an uplink frequency band (cell, component carrier, carrier) managed by base station device 3. The transmission processing unit of terminal device 1 transmits a HARQ-ACK for the PDSCH in a downlink frequency band (cell, component carrier, carrier) managed by base station device 3. The transmission processing unit of terminal device 1 transmits a HARQ-ACK for the PDSCH in a downlink frequency band (cell, component carrier, carrier) managed by base station device 3 in an uplink frequency band (cell, component carrier, carrier) managed by base station device 3.

The upper layer processing unit 14 outputs uplink data (transport blocks) generated by user operations, etc. to the radio transceiver unit 10. The upper layer processing unit 14 processes the MAC layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and RRC layer.

The media access control layer processing unit 15 provided in the upper layer processing unit 14 performs MAC layer processing.

The radio resource control layer processing unit 16 included in the upper layer processing unit 14 performs RRC layer processing. The radio resource control layer processing unit 16 manages various setting information/parameters of its own device. The radio resource control layer processing unit 16 sets various setting information/parameters based on upper layer signals received from the base station device 3. That is, the radio resource control layer processing unit 16 sets various setting information/parameters based on information indicating the various setting information/parameters received from the base station device 3. Note that the setting information may include information related to processing or setting of physical channels and physical signals (i.e., the physical layer), the MAC layer, the PDCP layer, the RLC layer, and the RRC layer. The parameters may be upper layer parameters.

The radio resource control layer processing unit 16 sets a control resource set based on the RRC signaling received from the base station device 3. The radio resource control layer processing unit 16 sets (configures) a search space within the control resource set. The radio resource control layer processing unit 16 sets (configures) PDCCH candidates to be monitored within the control resource set. The radio resource control layer processing unit 16 sets (configures) the number of PDCCH candidates to be monitored within the control resource set. The radio resource control processing unit 16 sets (configures) the aggregation level of the PDCCH candidates to be monitored within the control resource set.

The radio resource control layer processing unit 16 sets the DCI format to be monitored within the control resource set. The radio resource control layer processing unit 16 may also set the DCI format to be monitored within the search space. The radio resource control layer processing unit 16 sets the DCI format to be monitored within the control resource set based on RRC signaling indicated from the base station device 3. The radio resource control layer processing unit 16 may also set the DCI format to be monitored within the search space based on RRC signaling indicated from the base station device 3. The radio resource control layer processing unit 16 sets one or more DCI formats to be monitored in the reception processing unit.

The wireless transceiver unit 10 performs physical layer processing such as modulation, demodulation, encoding, and decoding. The wireless transceiver unit 10 separates, demodulates, and decodes the received physical signals, and outputs the decoded information to the upper layer processing unit 14. The wireless transceiver unit 10 generates physical signals by modulating, encoding, and generating baseband signals (converting to time-continuous signals) from the data, and transmits them to the base station device 3.

The RF unit 12 converts the signal received via the antenna unit 11 into a baseband signal by quadrature demodulation (downconvert) and removes unnecessary frequency components. The RF unit 12 outputs the processed analog signal to the baseband unit.

The baseband unit 13 converts the analog signal input from the RF unit 12 into a digital signal. The baseband unit 13 removes the portion corresponding to the cyclic prefix (CP) from the converted digital signal, and performs a fast Fourier transform (FFT) on the CP-removed signal to extract the frequency domain signal.

The baseband unit 13 performs an inverse fast Fourier transform (IFFT) on the data to generate OFDM symbols, adds a CP to the generated OFDM symbols, generates baseband digital signals, and converts the baseband digital signals to analog signals. The baseband unit 13 outputs the converted analog signals to the RF unit 12.

The RF unit 12 uses a low-pass filter to remove unnecessary frequency components from the analog signal input from the baseband unit 13, up-converts the analog signal to a carrier frequency, and transmits it via the antenna unit 11. The RF unit 12 also amplifies the power. The RF unit 12 may also have a function to control the transmission power. The RF unit 12 is also referred to as a transmission power control unit.

The terminal device 1 receives a PDCCH. The terminal device 1 receives a PDSCH. The radio resource control layer processing unit 16 sets a control resource set. The radio resource control layer processing unit 16 sets a search space. The radio resource control layer processing unit 16 sets a control resource set based on RRC signaling. The radio resource control layer processing unit 16 sets a search space based on RRC signaling. The receiving unit of the terminal device 1 monitors multiple PDCCH candidates within the search space of the set control resource set. The receiving unit of the terminal device 1 monitors multiple PDCCH candidates within the search space of the set control resource set in a certain slot. The receiving unit of the terminal device 1 monitors the PDCCH candidates assuming a DCI format. The decoding unit of the terminal device 1 decodes the monitored PDCCH candidates. The decoding unit of the terminal device 1 decodes the PDCCH candidates to obtain the downlink DCI format and recognizes the scheduling information of the PDSCH. The decoding unit of the terminal device 1 decodes the received PDSCH.

The receiver of the terminal device 1 monitors PDCCH candidates within a search area of a control resource set in a certain slot based on the number set based on RRC signaling. The receiver of the terminal device 1 monitors PDCCH candidates consisting of one or more OFDM symbols set based on RRC signaling within a search area of a control resource set in a certain slot. Note that the receiver of the terminal device 1 may set three or more search areas in a certain slot, each search area being a different OFDM symbol, and monitor PDCCH candidates further distributed within the slot. The receiver of the terminal device 1 monitors PDCCH candidates assuming a DCI format set based on RRC signaling.

Below, an example configuration of a base station device 3 relating to one aspect of this embodiment is described.

Figure 6 is a schematic block diagram showing the configuration of a base station device 3 according to one aspect of this embodiment. As shown in the figure, the base station device 3 includes a radio transceiver unit 30 and an upper layer processing unit 34. The radio transceiver unit 30 includes an antenna unit 31, an RF unit 32, and a baseband unit 33. The upper layer processing unit 34 includes a medium access control layer processing unit 35 and a radio resource control layer processing unit 36. The radio transceiver unit 30 is also referred to as a transmitter, receiver, or physical layer processing unit.

The upper layer processing unit 34 processes the MAC layer, PDCP layer, RLC layer, and RRC layer.

The media access control layer processing unit 35 provided in the upper layer processing unit 34 performs MAC layer processing.

The radio resource control layer processing unit 36 included in the upper layer processing unit 34 performs RRC layer processing. The radio resource control layer processing unit 36 generates downlink data (transport blocks), system information, RRC messages, MAC CEs, etc. to be allocated to the PDSCH, or acquires these from upper nodes, and outputs them to the radio transceiver unit 30. The radio resource control layer processing unit 36 also manages various setting information/parameters for each terminal device 1. The radio resource control layer processing unit 36 may set various setting information/parameters for each terminal device 1 via upper layer signals. In other words, the radio resource control layer processing unit 36 transmits/reports information indicating various setting information/parameters. Note that the setting information may include information related to processing or setting of physical channels and physical signals (i.e., the physical layer), the MAC layer, the PDCP layer, the RLC layer, and the RRC layer. The parameters may be upper layer parameters.

The radio resource control layer processing unit 36 sets a control resource set for the terminal device 1. Multiple PDCCH candidates are configured (set) within the set control resource set. The radio resource control layer processing unit 36 sets a search space for the terminal device 1. The radio resource control layer processing unit 36 sets a DCI format to be monitored in the search space for the terminal device 1. The radio resource control layer processing unit 36 sets resources for transmitting HARQ-ACK for the terminal device 1.

The radio resource control layer processing unit 36 sets the DCI format to be applied to the terminal device 1 within the control resource set. The radio resource control layer processing unit 36 generates RRC signaling indicating the DCI format to be applied to the terminal device 1. The radio resource control layer processing unit 36 sets one or more DCI formats to be applied in the transmission processing unit.

The functions of the radio transceiver unit 30 are similar to those of the radio transceiver unit 10, and therefore description thereof will be omitted where appropriate. The radio transceiver unit 30 also identifies the SS (search space) configured in the terminal device 1. The radio transceiver unit 30 identifies the search space within the control resource set configured in the terminal device 1. The radio transceiver unit 30 identifies the PDCCH candidates monitored in the terminal device 1 and identifies the search space. The radio transceiver unit 30 identifies which control channel elements each PDCCH candidate monitored in the terminal device 1 is configured from (identifies the numbers of the control channel elements from which the PDCCH candidate is configured). The radio transceiver unit 30 includes an SS identification unit, and the SS identification unit identifies the SS configured in the terminal device 1. The SS identification unit identifies one or more PDCCH candidates within the control resource set configured as the search space of the terminal device. The SS grasping unit grasps the PDCCH candidates (number of PDCCH candidates, PDCCH candidate numbers) configured in the search area of the control resource set of the terminal device 1.

The SS grasping unit grasps the configuration of the search area within the control resource set (number of PDCCH candidates, OFDM symbols of the PDCCH candidates, aggregation level of the PDCCH candidates). The transmitting unit (transmission processing unit) of the radio transceiver unit 30 transmits the PDCCH to the terminal device 1 using the PDCCH candidates within the search area of the control resource set.

The receiving unit (also referred to as the receiving processing unit) of base station device 3 receives the HARQ-ACK. The receiving processing unit of base station device 3 receives the HARQ-ACK for the PDSCH. The receiving processing unit of base station device 3 receives the HARQ-ACK in the uplink frequency band (cell, component carrier, carrier). The receiving processing unit of base station device 3 receives the HARQ-ACK for the PDSCH in the downlink frequency band (cell, component carrier, carrier) in the uplink frequency band (cell, component carrier, carrier).

Each of the units designated by reference numerals 10 to 16 in the terminal device 1 may be configured as a circuit. Each of the units designated by reference numerals 30 to 36 in the base station device 3 may be configured as a circuit.

The terminal device 1 transmits uplink control information (UCI) to the base station device 3. The terminal device 1 may multiplex the UCI onto the PUCCH and transmit it. The terminal device 1 may multiplex the UCI onto the PUSCH and transmit it. The UCI may include at least one of downlink channel state information (CSI), a scheduling request (SR) indicating a request for PUSCH resources, and a Hybrid Automatic Repeat request ACKnowledgement (HARQ-ACK) for downlink data (Transport block, Medium Access Control Protocol Data Unit (MAC PDU), Downlink-Shared Channel (DL-SCH), Physical Downlink Shared Channel (PDSCH)).

HARQ-ACK may also be referred to as ACK/NACK, HARQ feedback, HARQ-ACK feedback, HARQ response, HARQ-ACK response, HARQ information, HARQ-ACK information, HARQ control information, and HARQ-ACK control information.

If downlink data is successfully decoded, an ACK for the downlink data is generated. If downlink data is not successfully decoded, a NACK for the downlink data is generated. The HARQ-ACK may include at least a HARQ-ACK bit corresponding to at least one transport block. The HARQ-ACK bit may indicate an ACK (ACKnowledgement) or a NACK (Negative-ACKnowledgement) corresponding to one or multiple transport blocks. The HARQ-ACK may include at least a HARQ-ACK codebook including one or more HARQ-ACK bits. The HARQ-ACK bit corresponding to one or multiple transport blocks may correspond to a PDSCH including the one or multiple transport blocks.

HARQ control for one transport block may be referred to as an HARQ process. One HARQ process identifier may be given for each HARQ process. The DCI format includes a field indicating the HARQ process identifier.

An NDI (New Data Indicator) is indicated in the DCI format for each HARQ process. For example, the NDI field is included in the DCI format (DL assignment) containing PDSCH scheduling information. The NDI field is 1 bit. The terminal device 1 stores (memorizes) the NDI value for each HARQ process. The base station device 3 stores (memorizes) the NDI value for each HARQ process for each terminal device 1. The terminal device 1 updates the stored NDI value using the NDI field of the detected DCI format. The base station device 3 sets the updated NDI value or the non-updated NDI value in the NDI field of the DCI format and transmits it to the terminal device 1. The terminal device 1 updates the stored NDI value using the NDI field of the detected DCI format for the HARQ process corresponding to the value of the HARQ process identifier field of the detected DCI format.

The terminal device 1 determines whether the received transport block is a new transmission or a retransmission based on the value of the NDI field in the DCI format (DL assignment). The terminal device 1 compares the value of the NDI previously received for the transport block of a certain HARQ process with the value of the detected NDI field in the DCI format, and if the value of the NDI field is toggled, determines that the received transport block is a new transmission. When transmitting a transport block for a new transmission in a certain HARQ process, the base station device 3 toggles the value of the NDI stored for that HARQ process and transmits the toggled NDI to the terminal device 1. When transmitting a transport block for a retransmission in a certain HARQ process, the base station device 3 does not toggle the value of the NDI stored for that HARQ process and transmits an untoggled NDI to the terminal device 1. The terminal device 1 compares the value of the NDI field of the detected DCI format with the value of the NDI previously received for the transport block of a certain HARQ process, and if the value of the NDI field of the detected DCI format has not been toggled (is the same), determines that the received transport block is a retransmission. Note that toggling here means switching to a different value.

The terminal device 1 may report HARQ-ACK information to the base station device 3 using a HARQ-ACK codebook in a slot indicated by the value of the HARQ indication field included in DCI format 1_0 corresponding to PDSCH reception or DCI format 1_1.

For DCI format 1_0, the value of the HARQ indication field may be mapped to a set of slot numbers (1, 2, 3, 4, 5, 6, 7, 8). For DCI format 1_1, the value of the HARQ indication field may be mapped to a set of slot numbers given by the higher layer parameter dl-DataToUL-ACK. The slot number indicated based at least on the value of the HARQ indication field may also be referred to as HARQ-ACK timing or K1. For example, a HARQ-ACK indicating the decoding status of PDSCH (downlink data) transmitted in slot n may be reported (transmitted) in slot n+K1.

dl-DataToUL-ACK indicates a list of HARQ-ACK timings for the PDSCH. The timing is the number of slots between the slot in which the PDSCH is received (or the slot containing the last OFDM symbol to which the PDSCH is mapped) and the slot in which the HARQ-ACK for the received PDSCH is transmitted. For example, dl-DataToUL-ACK is a list of 1, 2, 3, 4, 5, 6, 7, or 8 timings. If dl-DataToUL-ACK is a list of 1 timing, the HARQ indication field is 0 bits. If dl-DataToUL-ACK is a list of 2 timings, the HARQ indication field is 1 bit. If dl-DataToUL-ACK is a list of 3 or 4 timings, the HARQ indication field is 2 bits. When the dl-DataToUL-ACK is a list of 5, 6, 7, or 8 timings, the HARQ indication field is 3 bits. For example, the dl-DataToUL-ACK is configured from a list of timings with any value in the range from 0 to 31. For example, the dl-DataToUL-ACK is configured from a list of timings with any value in the range from 0 to 63.

The size of the dl-DataToUL-ACK is defined as the number of elements it contains. The size of the dl-DataToUL-ACK may be referred to as L _para . The index of the dl-DataToUL-ACK indicates the order (number) of the elements of the dl-DataToUL-ACK. For example, if the size of the dl-DataToUL-ACK is 8 (L _para = 8), the index of the dl-DataToUL-ACK is any of 1, 2, 3, 4, 5, 6, 7, or 8. The index of the dl-DataToUL-ACK may be given, indicated, or indicated by the value indicated by the HARQ indication field.

The terminal device 1 may set the size of the HARQ-ACK codebook according to the size of the dl-DataToUL-ACK. For example, if the dl-DataToUL-ACK consists of eight elements, the size of the HARQ-ACK codebook is 8. For example, if the dl-DataToUL-ACK consists of two elements, the size of the HARQ-ACK codebook is 2. Each HARQ-ACK information that makes up the HARQ-ACK codebook is HARQ-ACK information for PDSCH reception at each slot timing of the dl-DataToUL-ACK. This type of HARQ-ACK codebook is also called a semi-static HARQ-ACK codebook.

An example of the setting of the HARQ indication field is explained below. For example, dl-DataToUL-ACK consists of a list of eight timings: 0, 7, 15, 23, 31, 39, 47, and 55, and the HARQ indication field consists of three bits. A HARQ indication field of "000" corresponds to the first timing, 0, in the dl-DataToUL-ACK list. In other words, a HARQ indication field of "000" corresponds to the value 0 indicated by index 1 in dl-DataToUL-ACK. A HARQ indication field of "001" corresponds to the second timing, 7, in the dl-DataToUL-ACK list. A HARQ indication field of "010" corresponds to the third timing, 15, in the dl-DataToUL-ACK list. The HARQ indication field of "011" corresponds to the fourth 23 in the list of dl-DataToUL-ACK as the corresponding timing. The HARQ indication field of "100" corresponds to the fifth 31 in the list of dl-DataToUL-ACK as the corresponding timing. The HARQ indication field of "101" corresponds to the sixth 39 in the list of dl-DataToUL-ACK as the corresponding timing. The HARQ indication field of "110" corresponds to the seventh 47 in the list of dl-DataToUL-ACK as the corresponding timing. The HARQ indication field of "111" corresponds to the eighth 55 in the list of dl-DataToUL-ACK as the corresponding timing. When the received HARQ indication field indicates "000", the terminal device 1 transmits the corresponding HARQ-ACK in the 0th slot from the slots of the received PDSCH. If the received HARQ indication field indicates "001", the terminal device 1 transmits the corresponding HARQ-ACK in the 7th slot from the slots of the received PDSCH. If the received HARQ indication field indicates "010", the terminal device 1 transmits the corresponding HARQ-ACK in the 15th slot from the slots of the received PDSCH. If the received HARQ indication field indicates "011", the terminal device 1 transmits the corresponding HARQ-ACK in the 23rd slot from the slots of the received PDSCH. If the received HARQ indication field indicates "100", the terminal device 1 transmits the corresponding HARQ-ACK in the 31st slot from the slots of the received PDSCH. If the received HARQ indication field indicates "101", the terminal device 1 transmits the corresponding HARQ-ACK in the 39th slot from the slots of the received PDSCH. If the received HARQ indication field indicates "110", the terminal device 1 transmits the corresponding HARQ-ACK in the 47th slot from the slots of the received PDSCH. If the received HARQ indication field indicates "111", the terminal device 1 transmits the corresponding HARQ-ACK in the 55th slot from the slots of the received PDSCH.

If the higher layer parameter pdsch-AggregationFactor is provided to the terminal device 1, N _PDSCH ^repeat may be the value of pdsch-AggregationFactor. If the higher layer parameter pdsch-AggregationFactor is not provided to the terminal device 1, N _PDSCH ^repeat may be 1. The terminal device 1 may report HARQ-ACK information for PDSCH reception from slot n-N _PDSCH ^repeat +1 to slot n using PUCCH transmission and/or PUSCH transmission in slot n+k. Here, k may be the number of slots indicated by the HARQ indication field included in the DCI format corresponding to the PDSCH reception. Also, if the HARQ indication field is not included in the DCI format, k may be provided by the higher layer parameter dl-DataToUL-ACK.

When the terminal device 1 is configured to monitor a PDCCH including DCI format 1_0 and not to monitor a PDCCH including DCI format 1_1, the HARQ-ACK timing value K1 may be some or all of (1, 2, 3, 4, 5, 6, 7, 8). When the terminal device 1 is configured to monitor a PDCCH including DCI format 1_1, the HARQ-ACK timing value K1 may be given by the upper layer parameter dl-DataToUL-ACK.

The terminal device 1 determines a set of multiple opportunities for receiving one or more candidate PDSCHs for transmitting corresponding HARQ-ACK information on the PUCCH of a certain slot. The terminal device 1 may determine multiple slots of slot timing K1 included in dl-DataToUL-ACK as multiple opportunities for receiving candidate PDSCHs. K1 may be a set of k. For example, if dl-DataToUL-ACK is (1, 2, 3, 4, 5, 6, 7, 8), HARQ-ACK information for PDSCH reception in slot n-1, PDSCH reception in slot n-2, PDSCH reception in slot n-3, PDSCH reception in slot n-4, PDSCH reception in slot n-5, PDSCH reception in slot n-6, PDSCH reception in slot n-7, and PDSCH reception in slot n-8 is transmitted on the PUCCH of slot n. If the terminal device 1 actually receives a PDSCH in a slot corresponding to the candidate PDSCH reception, it sets ACK or NACK as the HARQ-ACK information based on the transport block contained in that PDSCH, and if it does not receive a PDSCH in the slot corresponding to the candidate PDSCH reception, it sets NACK as the HARQ-ACK information.

The HARQ indication field included in the DCI format received on the PDCCH in slot n-1 indicates 1. The HARQ indication field included in the DCI format received on the PDCCH in slot n-2 indicates 2. The HARQ indication field included in the DCI format received on the PDCCH in slot n-3 indicates 3. The HARQ indication field included in the DCI format received on the PDCCH in slot n-4 indicates 4. The HARQ indication field included in the DCI format received on the PDCCH in slot n-5 indicates 5. The HARQ indication field included in the DCI format received on the PDCCH in slot n-6 indicates 6. The HARQ indication field included in the DCI format received on the PDCCH in slot n-7 indicates 7. The HARQ indication field included in the DCI format received on the PDCCH in slot n-8 indicates 8.

Based on the slot in which the PDCCH was received and the value of the HARQ indication field included in the received DCI format, the terminal device 1 determines the slot in which to transmit HARQ-ACK information and the set of multiple candidate PDSCH reception slots corresponding to that HARQ-ACK information. For example, if dl-DataToUL-ACK is (1, 2, 3, 4, 5, 6, 7, 8), the terminal device 1 receives the PDCCH in slot m, and the HARQ indication field included in the DCI format indicates 4. The terminal device 1 determines to transmit HARQ-ACK information in slot (m+4). The terminal device 1 determines that the other HARQ-ACK information to be transmitted in slot (m+4) is HARQ-ACK information for PDSCH reception in slot (m+(1-4)), HARQ-ACK information for PDSCH reception in slot (m+(2-4)), HARQ-ACK information for PDSCH reception in slot (m+(3-4)), HARQ-ACK information for PDSCH reception in slot (m+(5-4)), HARQ-ACK information for PDSCH reception in slot (m+(6-4)), HARQ-ACK information for PDSCH reception in slot (m+(7-4)), and HARQ-ACK information for PDSCH reception in slot (m+(8-4)).

In the above, the Semi-static HARQ-ACK codebook was described as a type of HARQ-ACK codebook, but different types of HARQ-ACK codebooks may also be used. Here, we will describe a type of HARQ-ACK codebook called the Dynamic HARQ-ACK codebook.

The HARQ-ACK codebook corresponding to a certain PDSCH group is determined based on one or more HARQ-ACK bits corresponding to one or more transport blocks included in one or more PDSCHs included in the certain PDSCH group. The HARQ-ACK codebook is determined based on at least the set of monitoring occasions for PDCCH and some or all of the value of the counter DAI field. The HARQ-ACK codebook may be further determined based on the value of the UL DAI field. The HARQ-ACK codebook may be further determined based on the value of the DAI field. The HARQ-ACK codebook may be further determined based on the value of the total DAI field.

The HARQ-ACK codebook size of the Dynamic HARQ-ACK codebook is based on a field in the DCI format. The size of the HARQ-ACK codebook may be set based on the value of the Counter DAI field in the last received DCI format. The Counter DAI field indicates the cumulative number of PDSCHs or transport blocks scheduled until reception of the corresponding DCI format. The Counter DAI field may also indicate the cumulative number of PDCCHs transmitted until reception of the corresponding DCI format. The size of the HARQ-ACK codebook may be set based on the value of the Total DAI field in the DCI format. The Total DAI field indicates the total number of PDSCHs or transport blocks scheduled until transmission of the HARQ-ACK codebook. The Total DAI field may indicate the total number of PDCCHs transmitted until the transmission of the HARQ-ACK codebook.

The terminal device 1 may determine a set of PDCCH monitoring opportunities for HARQ-ACK information transmitted in a PUCCH allocated to a slot with index n (slot #n) based at least on the value of timing K1 and part or all of the value of slot offset K0. The set of PDCCH monitoring opportunities for HARQ-ACK information transmitted in a PUCCH allocated to a slot with index n is also referred to as a set of PDCCH monitoring opportunities for slot n (monitoring occasions for PDCCH for slot #n). Here, the set of PDCCH monitoring opportunities includes M PDCCH monitoring opportunities. For example, the slot offset K0 may be indicated based at least on the value of a time domain resource allocation field included in the downlink DCI format. The slot offset K0 is a value indicating the number of slots (slot difference) from the slot including the last OFDM symbol in which a PDCCH including a DCI format including a time domain resource allocation field indicating the slot offset K0 is placed to the first OFDM symbol of a PDSCH scheduled by the DCI format.

If a DCI format detected in a monitoring opportunity of any search space set corresponding to a certain PDCCH monitoring opportunity triggers (contains triggering information) the transmission of HARQ-ACK information in slot n, the terminal device 1 may determine that PDCCH monitoring opportunity as a PDCCH monitoring opportunity for slot n. Also, if a DCI format detected in a monitoring opportunity of a search space set corresponding to a certain PDCCH monitoring opportunity does not trigger (contains triggering information) the transmission of HARQ-ACK information in slot n, the terminal device 1 may not determine that PDCCH monitoring opportunity as a PDCCH monitoring opportunity for slot n. Also, if no DCI format is detected in a monitoring opportunity of a search space set corresponding to a certain PDCCH monitoring opportunity, the terminal device 1 may not determine that PDCCH monitoring opportunity as a PDCCH monitoring opportunity for slot n.

The PUCCH resource used for transmitting HARQ-ACK information in slot n may be identified based at least on a PUCCH resource indication field included in the last DCI format among one or more DCI formats detected in a set of PDCCH monitoring opportunities for that slot n. Here, each of the one or more DCI formats triggers the transmission of HARQ-ACK information in slot n. The last DCI format may be the DCI format corresponding to the last index (highest index) among the DCI formats detected in the set of PDCCH monitoring opportunities for that slot n. The indices of the DCI formats in the set of PDCCH monitoring opportunities for that slot n are given in ascending order relative to the index of the serving cell in which the DCI format is detected, and then in ascending order relative to the index of the PDCCH monitoring opportunity in which the DCI format is detected. The indices of the PDCCH monitoring opportunities are given in ascending order on the time axis.

The Counter DAI indicates, for a PDCCH monitoring opportunity in a serving cell among M PDCCH monitoring opportunities, the cumulative number of PDCCHs detected up to the PDCCH monitoring opportunity in the serving cell (or a value at least related to the cumulative number). The Counter DAI may also be referred to as C-DAI. The C-DAI corresponding to a PDSCH may be indicated by a field included in the DCI format used for scheduling the PDSCH. The Total DAI may indicate the cumulative number of PDCCHs detected up to PDCCH monitoring opportunity m among M PDCCH monitoring opportunities (or a value at least related to the cumulative number). The Total DAI may also be referred to as T-DAI (Total Downlink Assignment Index).

Figure 7 is a diagram showing an example of the number of PDCCH candidates configured for each slot. Here, configured PDCCH candidates refer to PDCCH candidates configured by RRC signaling parameters. Base station device 3 notifies terminal device 1 of the number of PDCCH candidates in the search space for each slot using RRC signaling. Terminal device 1 is notified of the number of PDCCH candidates in the search space for each slot by base station device 3 using RRC signaling. Note that multiple search space parameters (period, number of PDCCH candidates per aggregation level) are notified to terminal device 1 from base station device 3, and the total number of PDCCH candidates in one or more search spaces configured for each slot is shown in Figure 7. For example, if a search region is configured with a period of every 8 slots starting from slot #2 and in which five aggregation level 1 PDCCH candidates are configured, and another search region is configured with a period of every 4 slots starting from slot #2 and in which two aggregation level 2 PDCCH candidates, one aggregation level 4 PDCCH candidate, and two aggregation level 8 PDCCH candidates are configured, the number of PDCCH candidates configured in slot #2 will be 10, which is the sum of the respective PDCCH candidates (5 + 2 + 1 + 2).

Multiple upper limit values (a first upper limit value, a second upper limit value) are used in the terminal device 1. The upper limit values are for the number of PDCCH candidates to be monitored, and are used to adjust (drop) PDCCH candidates configured in the terminal device 1. The multiple upper limit values may be set based on the capabilities of the terminal device 1, and the terminal device 1 may notify the base station device 3 of information regarding the multiple upper limit values. The multiple upper limit values may be set (configured) in the base station device 3, and a parameter indicating the multiple upper limit values set using RRC signaling may be notified to the terminal device 1, and the terminal device 1 may set the multiple upper limit values based on the RRC signaling. The first upper limit value is used in units of one slot. The second upper limit value is used in units of multiple slots. The first upper limit value is an upper limit value for the number of PDCCH candidates to be monitored in one slot. The second upper limit value is an upper limit value for PDCCH candidates to be monitored in multiple slots. The first upper limit value may be an upper limit value used for monitoring PDCCH candidates including a DCI format for single-slot scheduling (a first DCI format). The second upper limit value may be an upper limit value used for monitoring PDCCH candidates including a DCI format for multi-slot scheduling (second DCI format). The second upper limit value may be an upper limit value used for monitoring both PDCCH candidates including a DCI format for multi-slot scheduling and PDCCH candidates including a DCI format for single-slot scheduling.

As an example, we will explain the case where 8 is set as the first upper limit value and 45 is set as the second upper limit value. We will also explain the case where the second upper limit value is used in units of 8 slots. A DCI format for multi-slot scheduling is configured for the search area configured for slot #0. A DCI format for single-slot scheduling is configured for the search areas of slot #2, slot #5, and slot #6.

First, the terminal device 1 determines whether the number of PDCCH candidates configured for each slot exceeds a first upper limit. Here, the terminal device 1 determines whether the number of PDCCH candidates, which may include DCI formats for single-slot scheduling, exceeds a first upper limit. Since there are 10 PDCCH candidates configured for slot #2, which exceeds the first upper limit of 8, the terminal device 1 drops the PDCCH candidates configured for slot #2 and adjusts the number of monitored PDCCH candidates to 8 or less (smaller). Since there are 5 PDCCH candidates configured for slot #5, which does not exceed the first upper limit of 8, the terminal device 1 does not adjust (does not drop, reduce, or decrease) the configured PDCCH candidates. Since there are 5 PDCCH candidates configured for slot #6, which does not exceed the first upper limit of 8, the terminal device 1 does not adjust (does not drop, reduce, or decrease) the configured PDCCH candidates.

Next, the terminal device 1 determines whether the number of PDCCH candidates configured for the eight slots exceeds a second upper limit. Here, for slots where the number of configured PDCCH candidates exceeds the first upper limit, adjusted PDCCH candidates are used. There are 30 PDCCH candidates configured in slot #0, where the DCI format for multi-slot scheduling is configured; 8 PDCCH candidates adjusted based on the first upper limit in slot #2, where the DCI format for single-slot scheduling is configured; 5 PDCCH candidates configured in slot #5, where the DCI format for single-slot scheduling is configured; and 5 PDCCH candidates configured in slot #6, where the DCI format for single-slot scheduling is configured. Since the total number of PDCCH candidates is 48, which exceeds the second upper limit of 45, the terminal device 1 drops (at least (48 - 45) = 3) PDCCH candidates and adjusts the number of monitored PDCCH candidates so that they are equal to or less than the second upper limit. The terminal device 1 may preferentially drop PDCCH candidates in a search space with the highest or lowest search space number among eight slots. The terminal device 1 may preferentially drop PDCCH candidates in a search space in which a DCI format for multi-slot scheduling is configured. The terminal device 1 may preferentially drop PDCCH candidates in a search space in the first or last slot.

For example, the terminal device 1 drops three PDCCH candidates from among the PDCCH candidates configured for slot #0, and sets the number of PDCCH candidates monitored in slot #0 to 27. For example, the terminal device 1 drops three PDCCH candidates from among the PDCCH candidates configured for slot #6, and sets the number of PDCCH candidates monitored in slot #6 to 2. For example, if five PDCCH candidates are configured in a search area of one configuration in slot #6, the terminal device 1 may drop all five PDCCH candidates configured for slot #6. In other words, the terminal device 1 may drop PDCCH candidates in search area configuration units within a slot. If search areas of multiple configurations are configured within a slot, the terminal device 1 may preferentially monitor PDCCH candidates in search areas of configurations with smaller search area numbers, and preferentially drop PDCCH candidates in search areas of configurations with larger search area numbers.

In the above, as an example, the first upper limit value is described as 8, but it may be a different value. In the above, as an example, the second upper limit value is described as 45, but it may be a different value. In the above, as an example, the number of slots for which adjustment of PDCCH candidates monitored using the second upper limit value is performed is described as 8, but it may be a different value.

The reception processing unit of the terminal device 1 adjusts (drops, reduces, or decreases) the PDCCH candidates configured for each slot so that the number of PDCCH candidates monitored in each slot does not exceed a first upper limit. The reception processing unit of the terminal device 1 determines, for each slot, whether the number of PDCCH candidates configured for that slot exceeds the first upper limit. Here, the PDCCH candidates to be adjusted are in a DCI format that uses a DCI format for single-slot scheduling (first DCI format). If the reception processing unit of the terminal device 1 determines that the number of PDCCH candidates configured for that slot exceeds the first upper limit, it drops (reduces, or decreases) one or more of the PDCCH candidates configured for that slot so that the number of PDCCH candidates monitored for that slot is within the first upper limit. If the reception processing unit of the terminal device 1 determines that the number of PDCCH candidates configured for that slot does not exceed the first upper limit, it does not drop (does not reduce, or decrease) the PDCCH candidates configured for that slot.

The reception processing unit of the terminal device 1 adjusts (drops, reduces, or decreases) the PDCCH candidates configured for multiple slots or the PDCCH candidates adjusted based on the first upper limit value so that the number of PDCCH candidates monitored in multiple slots does not exceed the second upper limit value. The reception processing unit of the terminal device 1 determines whether the sum of the PDCCH candidates configured for one or more slots and the PDCCH candidates adjusted based on the first upper limit value for one or more slots exceeds the second upper limit value. As described above, for slots in which a search space in which a DCI format for single-slot scheduling is configured is configured, the PDCCH candidates are adjusted based on the first upper limit value (including cases where the PDCCH candidates configured as a result of a determination based on the first upper limit value are not dropped (not reduced, not decreased)), and the adjusted number of PDCCH candidates is used for the determination based on the second upper limit value. For slots in which a DCI format for single-slot scheduling is not configured and a search space in which a DCI format for multi-slot scheduling is configured, adjustment of PDCCH candidates based on the first upper limit value is not performed, and the number of configured PDCCH candidates is used for judgment based on the second upper limit value.

When the reception processing unit of the terminal device 1 determines that the sum of the PDCCH candidates configured for one or more slots and the PDCCH candidates adjusted for one or more slots based on the first upper limit value exceeds the second upper limit value, the reception processing unit drops one or more PDCCH candidates from the configured PDCCH candidates, or drops one or more PDCCH candidates from the adjusted PDCCH candidates, or drops one or more PDCCH candidates from each of the configured PDCCH candidates and the adjusted PDCCH candidates, thereby adjusting the number of PDCCH candidates to be monitored so that the total number of PDCCH candidates to be monitored in the multiple slots is within the second upper limit value. When the reception processing unit of the terminal device 1 determines that the sum of the PDCCH candidates configured for one or more slots and the PDCCH candidates adjusted for one or more slots based on the first upper limit value does not exceed the second upper limit value, the reception processing unit does not drop the configured PDCCH candidates and the adjusted PDCCH candidates in the multiple slots, and monitors the PDCCH candidates. As described above, the SS grasping unit of the base station device 3 grasps the PDCCH candidates monitored by the reception processing unit of the terminal device 1. The base station device 3 transmits a PDCCH to the terminal device 1 using one of the grasped PDCCH candidates.

The radio resource control layer processing unit 16 of the terminal device 1 configures a search area that includes at least the number of PDCCH candidates for each period, offset, and aggregation level, and a DCI format, and configures PDCCH candidates for each DCI format for each slot based on RRC signaling that indicates the configuration of multiple search areas. The radio resource control layer processing unit 36 of the base station device 3 configures a search area that includes at least the number of PDCCH candidates for each period, offset, and aggregation level, and a DCI format, and configures PDCCH candidates for each DCI format for each slot for the terminal device 1, and generates RRC signaling that indicates the configuration of multiple search areas.

As described above, one aspect of the present invention enables efficient transmission and reception of downlink control channels between a terminal device 1 and a base station device 3 while reducing the processing load on the terminal device 1. Single-slot scheduling can be efficiently supported while reducing the processing load on the terminal device 1 related to monitoring PDCCHs in multiple slots. In a situation where both multi-slot scheduling and single-slot scheduling are used, the load related to buffering received signals can be reduced by limiting the number of PDCCH candidates for single-slot scheduling to the number of PDCCH candidates that the terminal device 1 can process in a short time. The base station device 3 can flexibly configure the configuration of the search space taking into account the situations of multiple terminal devices 1. Meanwhile, if monitoring the configured PDCCH candidates locally exceeds the processing load of the downlink control channel in the terminal device 1, the monitoring process of the PDCCH candidates can be limited to within the processing capacity of the terminal device 1, thereby achieving efficient communications.

The following describes various aspects of the device relating to one aspect of this embodiment.

(1) In order to achieve the above object, one aspect of the present invention employs the following means. That is, a first aspect of the present invention is a terminal device comprising a processor and a memory for storing computer program code, the terminal device receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level, configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search area, and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot, and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates monitored in that slot. adjusting the number of PDCCH candidates monitored in the plurality of slots using a second upper limit value, wherein if a total number of PDCCH candidates adjusted based on the first upper limit value for the plurality of slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates adjusted for at least one slot to set the number of PDCCH candidates monitored in the plurality of slots; and if a total number of PDCCH candidates set based on the first upper limit value for the plurality of slots does not exceed the second upper limit value, not dropping the PDCCH candidates adjusted based on the first upper limit value and setting the number of PDCCH candidates adjusted based on the first upper limit value for the plurality of slots.

(2) Furthermore, the PDCCH candidates whose number is adjusted based on the first upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used, and the PDCCH candidates whose number is adjusted based on the second upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used and PDCCH candidates whose DCI format for multi-slot scheduling is used.

(3) A second aspect of the present invention is a base station device comprising a processor and a memory for storing computer program code, the base station device transmitting RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level, the base station device configuring PDCCH candidates for each slot to a terminal device based on the RRC signaling indicating the configuration of the search areas, and determining the number of PDCCH candidates monitored in each slot using a first upper limit value in the terminal device, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to determine the number of PDCCH candidates monitored in that slot, and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, the terminal device performs operations including: determining the number of PDCCH candidates monitored in the slot without dropping the PDCCH candidates configured for that slot; determining the number of PDCCH candidates monitored in multiple slots using a second upper limit value in the terminal device, wherein if the total number of PDCCH candidates determined based on the first upper limit value for multiple slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates determined for at least one slot to determine the number of PDCCH candidates monitored in the multiple slots; and if the total number of PDCCH candidates configured based on the first upper limit value for multiple slots does not exceed the second upper limit value, not dropping the PDCCH candidates determined based on the first upper limit value and determining the number of PDCCH candidates determined based on the first upper limit value for multiple slots.

(4) Furthermore, the number of PDCCH candidates determined based on the first upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling, and the number of PDCCH candidates determined based on the second upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling and PDCCH candidates that use a DCI format for multi-slot scheduling.

(5) A third aspect of the present invention is a communication method used in a terminal device, comprising the steps of: receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level; configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search area; and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot; and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates configured for that slot. and adjusting the number of PDCCH candidates monitored in multiple slots using a second upper limit value, wherein, if a total number of PDCCH candidates adjusted based on the first upper limit value for multiple slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates adjusted for at least one slot to set the number of PDCCH candidates monitored in the multiple slots, and if a total number of PDCCH candidates set based on the first upper limit value for multiple slots does not exceed the second upper limit value, not dropping the PDCCH candidates adjusted based on the first upper limit value and setting the number of PDCCH candidates adjusted based on the first upper limit value for multiple slots.

(6) Furthermore, the PDCCH candidates whose number is adjusted based on the first upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used, and the PDCCH candidates whose number is adjusted based on the second upper limit value are PDCCH candidates whose DCI format for single-slot scheduling is used and PDCCH candidates whose DCI format for multi-slot scheduling is used.

(7) A fourth aspect of the present invention is a communication method used in a base station device, comprising the steps of: transmitting RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level; configuring PDCCH candidates for each slot to a terminal device based on the RRC signaling indicating the configuration of the search areas; and determining the number of PDCCH candidates to be monitored in each slot using a first upper limit value in the terminal device, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to determine the number of PDCCH candidates to be monitored in that slot; and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, dropping at least some of the PDCCH candidates configured for that slot to determine the number of PDCCH candidates to be monitored in that slot. and determining the number of PDCCH candidates monitored in a slot by using a second upper limit value in the terminal device, wherein, when a total number of PDCCH candidates determined based on the first upper limit value for a plurality of slots exceeds the second upper limit value, at least a portion of the PDCCH candidates determined for at least one slot is dropped to determine the number of PDCCH candidates monitored in the plurality of slots, and when a total number of PDCCH candidates determined based on the first upper limit value for a plurality of slots does not exceed the second upper limit value, not dropping the PDCCH candidates determined based on the first upper limit value, and determining the number of PDCCH candidates determined based on the first upper limit value for a plurality of slots.

(8) Furthermore, the number of PDCCH candidates determined based on the first upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling, and the number of PDCCH candidates determined based on the second upper limit value are PDCCH candidates that use a DCI format for single-slot scheduling and PDCCH candidates that use a DCI format for multi-slot scheduling.

The programs running on the base station device 3 and terminal device 1 relating to one aspect of the present invention may be programs (programs that cause a computer to function) that control a CPU (Central Processing Unit) or the like so as to realize the functions of the above-described embodiment relating to one aspect of the present invention. Information handled by these devices is temporarily stored in RAM (Random Access Memory) during processing, and then stored in various ROMs such as Flash ROM (Read Only Memory) or HDD (Hard Disk Drive), and is read, modified, and written by the CPU as needed.

In addition, a portion of the terminal device 1 and base station device 3 in the above-described embodiment may be implemented by a computer. In this case, the program for implementing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to implement the function.

Note that the term "computer system" here refers to a computer system built into the terminal device 1 or base station device 3, and includes hardware such as the OS and peripheral devices. Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into the computer system.

Furthermore, "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a fixed period of time, such as volatile memory within a computer system that serves as a server or client in such cases. Furthermore, the above-mentioned program may be one that realizes part of the functions described above, or may be one that can realize the functions described above in combination with a program already stored in the computer system.

The terminal device 1 may comprise at least one processor and at least one memory containing computer program instructions (computer program). The memory and computer program instructions (computer program) may be configured to cause the terminal device 1 to perform the operations and processing described in the above embodiments using the processor. The base station device 3 may comprise at least one processor and at least one memory containing computer program instructions (computer program). The memory and computer program instructions (computer program) may be configured to cause the base station device 3 to perform the operations and processing described in the above embodiments using the processor.

Furthermore, the base station device 3 in the above-described embodiment can also be realized as a collection (device group) consisting of multiple devices. Each of the devices constituting the device group may have some or all of the functions or functional blocks of the base station device 3 related to the above-described embodiment. It is sufficient for the device group to have all of the functions or functional blocks of the base station device 3. Furthermore, the terminal device 1 related to the above-described embodiment can also communicate with the base station device as a collection.

Furthermore, the base station device 3 in the above-described embodiments may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network) and/or an NG-RAN (NextGen RAN, NR RAN).Furthermore, the base station device 3 in the above-described embodiments may have some or all of the functions of an upper node for an eNodeB and/or a gNB.

Furthermore, some or all of the terminal device 1 and base station device 3 in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit, or as a chipset. Each functional block of the terminal device 1 and base station device 3 may be individually formed into a chip, or some or all may be integrated into a chip. Furthermore, the integrated circuit method is not limited to LSI, and may be realized using a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

In addition, in the above-mentioned embodiment, a terminal device is described as an example of a communication device, but the present invention is not limited to this and can also be applied to terminal devices or communication devices such as stationary or non-mobile electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning/washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the invention. Furthermore, various modifications of one aspect of the present invention are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiments are substituted for elements that achieve the same effect are also included.

One aspect of the present invention can be used, for example, in communication systems, communication equipment (e.g., mobile phone devices, base station devices, wireless LAN devices, or sensor devices), integrated circuits (e.g., communication chips), or programs.

1 (1A, 1B, 1C) Terminal device 3 Base station device 10, 30 Radio transmission/reception unit 11, 31 Antenna unit 12, 32 RF unit 13, 33 Baseband unit 14, 34 Upper layer processing unit 15, 35 Medium access control layer processing unit 16, 36 Radio resource control layer processing unit

Claims (3)

A terminal device having a processor and a memory for storing computer program code, the terminal device receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level, configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search areas, and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, where if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot, and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates configured for that slot. a terminal device that performs operations including: not dropping a PDCCH candidate that has been adjusted based on the first upper limit value, and setting the number of PDCCH candidates to be monitored in that slot; adjusting the number of PDCCH candidates to be monitored in multiple slots using a second upper limit value, where if the total number of PDCCH candidates adjusted based on the first upper limit value for the multiple slots exceeds the second upper limit value, dropping at least some of the PDCCH candidates adjusted for at least one slot and setting the number of PDCCH candidates to be monitored in the multiple slots; and if the total number of PDCCH candidates set based on the first upper limit value for the multiple slots does not exceed the second upper limit value, not dropping the PDCCH candidates adjusted based on the first upper limit value, and setting the number of PDCCH candidates adjusted based on the first upper limit value for the multiple slots. The terminal device according to claim 1, wherein the PDCCH candidates whose number is adjusted based on the first upper limit are PDCCH candidates that use a DCI format for single-slot scheduling, and the PDCCH candidates whose number is adjusted based on the second upper limit are PDCCH candidates that use a DCI format for single-slot scheduling and PDCCH candidates that use a DCI format for multi-slot scheduling. A communication method used in a terminal device, comprising the steps of: receiving RRC signaling indicating a configuration of a search area including at least a period, an offset, and the number of PDCCH candidates for each aggregation level; configuring PDCCH candidates for each slot based on the RRC signaling indicating the configuration of the search areas; and adjusting the number of PDCCH candidates monitored in each slot using a first upper limit value, wherein if the number of PDCCH candidates configured for a slot exceeds the first upper limit value, at least some of the PDCCH candidates configured for that slot are dropped to set the number of PDCCH candidates monitored in that slot; and if the number of PDCCH candidates configured for a slot does not exceed the first upper limit value, adjusting the number of PDCCH candidates configured for that slot. a step of adjusting the number of PDCCH candidates monitored in multiple slots using a second upper limit value, wherein if the total number of PDCCH candidates adjusted based on the first upper limit value for the multiple slots exceeds the second upper limit value, at least some of the PDCCH candidates adjusted for at least one slot are dropped to set the number of PDCCH candidates monitored in the multiple slots; and if the total number of PDCCH candidates set based on the first upper limit value for the multiple slots does not exceed the second upper limit value, the step of not dropping the PDCCH candidates adjusted based on the first upper limit value and setting the number of PDCCH candidates adjusted based on the first upper limit value for the multiple slots.