JP2020074500A - Terminal device, base station device, communication method, and integrated circuit - Google Patents

Abstract

To provide efficient communication between a terminal device and a base station device for introduction of uplink asynchronous HARQ in 3GPP.SOLUTION: A base station device 3 includes: a receiving unit receiving an initial transmission of a transport block; and a transmission unit selecting a search space based on a type of random access procedure corresponding to a random access response including an uplink grant for the initial transmission of the transport block and transmitting a PDCCH for re-transmitting the transport block in the selected search spacey.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a terminal device, a base station device, a communication method, and an integrated circuit.

Cellular mobile radio access methods and networks (Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access: EUTRA, Evolved Universal Terrestrial Radio Access Network: EUTRAN, and New Radio) It is being considered in the 3rd Generation Partnership Project (3GPP). The base station device is an eNodeB (evolved NodeB) or a gNode.
Also referred to as B. The terminal device is also referred to as UE (User Equipment). 1 is a cellular communication system in which a plurality of areas covered by a base station device are arranged in cells. A single base station device may manage a plurality of cells.

A HARQ (Hybrid Automatic Repeat reQuest) function is provided in a MAC (Medium Access Control) layer. The HARQ function in the downlink has the characteristic of asynchronous HARQ, and the HARQ function in the uplink has the characteristic of synchronous HARQ (Non-Patent Document 1). 3G
In PP, introduction of asynchronous HARQ in the uplink is under study (Non-Patent Document 2).

"3GPP TS 36.300 v12.4.0 Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2", 7th November 2015. "UL HARQ considerations for LTE LAA", R2-151551, NVIDIA, 3GPP TSG RAN WG2 Meeting # 89bis, 20th-24th April 2015.

  The present invention has been made in view of the above points, and an object thereof is to use a terminal device capable of efficiently communicating with a base station device, an integrated circuit mounted on the terminal device, and the terminal device. An object of the present invention is to provide a communication method, a base station device that communicates with the terminal device, a communication method used in the base station device, and an integrated circuit mounted in the base station device.

  (1) In order to achieve the above object, the embodiment of the present invention takes the following means. That is, a first aspect of the present invention is a terminal device, which is a random access response including a transmission unit that performs initial transmission of a transport block and an uplink grant for the initial transmission of the transport block. Selecting a search space based on the type of the corresponding random access procedure and attempting to decode the PDCCH for retransmission of the transport block in the selected search space.

(2) A second aspect of the present invention is a base station apparatus, which includes a receiving unit that receives initial transmission of a transport block, and a random number that includes an uplink grant for the initial transmission of the transport block. And a transmitter for selecting a search space based on a type of a random access procedure to which the access response corresponds and transmitting a PDCCH for retransmission of the transport block in the selected search space.

  (3) A third aspect of the present invention is a communication method used in a terminal device, which performs initial transmission of a transport block, and includes an uplink grant for the initial transmission of the transport block. A search space is selected based on the type of random access procedure to which the random access response corresponds, and an attempt is made to decode the PDCCH for retransmission of the transport block in the selected search space.

  (4) A fourth aspect of the present invention is a communication method used in a base station apparatus, which receives an initial transmission of a transport block and includes an uplink grant for the initial transmission of the transport block. The search space is selected based on the type of the random access procedure to which the random access response corresponding thereto corresponds, and the PDCCH for retransmission of the transport block is transmitted in the selected search space.

  (5) A fifth aspect of the present invention is a terminal apparatus, which includes a receiving unit that decodes a PDCCH including an uplink grant, and a medium access control layer processing unit that manages a plurality of HARQ processes, The HARQ process corresponding to the uplink grant is determined based at least on the search space in which the PDCCH is decoded.

  (6) A sixth aspect of the present invention is a base station apparatus, which includes a transmission section that transmits a PDCCH including an uplink grant, and a medium access control layer processing section that manages a plurality of HARQ processes. The HARQ process corresponding to the uplink grant is determined based at least on the search space in which the PDCCH is transmitted.

  According to the present invention, the terminal device can efficiently communicate with the base station device.

It is a conceptual diagram of the radio | wireless communications system of this embodiment. It is a figure which shows an example of the structure of the MAC layer with respect to the uplink in which the carrier aggregation in this embodiment was set. It is a figure which shows schematic structure of the radio | wireless frame of this embodiment. It is a table which shows an example of UL-DL setting in this embodiment. It is a figure which shows an example of the synchronous HARQ in this embodiment. It is a figure which shows an example of the asynchronous HARQ in this embodiment. FIG. 6 is a diagram illustrating pseudo code for decoding PDCCH for HARQ retransmission. It is a schematic block diagram which shows the structure of the terminal device 1 of this embodiment. It is a schematic block diagram which shows the structure of the base station apparatus 3 of this embodiment.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a conceptual diagram of a wireless communication system of this embodiment. In FIG. 1, the wireless communication system includes terminal devices 1A to 1C and a base station device 3. Hereinafter, the terminal devices 1A to 1C are referred to as the terminal device 1.

  Hereinafter, carrier aggregation will be described.

In this embodiment, the terminal device 1 is configured with one or more serving cells. A technique in which the terminal device 1 communicates via a plurality of serving cells is referred to as cell aggregation or carrier aggregation. The present invention may be applied to each of the plurality of serving cells set for the terminal device 1. Further, the present invention may be applied to a part of the plurality of set serving cells. Further, the present invention may be applied to each of the plurality of configured groups of serving cells. Further, the present invention may be applied to a part of the set group of the plurality of serving cells. In carrier aggregation, the plurality of configured serving cells are also referred to as aggregated serving cells. Hereinafter, this embodiment is applied to a primary cell or one serving cell unless otherwise specified.

The wireless communication system of this embodiment is applied with TDD (Time Division Duplex) and / or FDD (Frequency Division Duplex). In case of cell aggregation,
FDD may be applied to all of the plurality of serving cells. In the case of cell aggregation, TDD may be applied to all of a plurality of serving cells. Also, in the case of cell aggregation, the serving cell to which TDD is applied and the serving cell to which FDD is applied may be aggregated.

The configured one or more serving cells include one primary cell and 0 or more than 0 secondary cells. The primary cell is a cell in which an initial connection establishment procedure is performed, a cell in which a connection re-establishment procedure is started, or a cell designated as a primary cell in a handover procedure. RRC (Radio Resource)
Control) The secondary cell may be set / added at the time when the connection is established or later.

  In the downlink, a carrier corresponding to a serving cell is called a downlink component carrier. In the uplink, a carrier corresponding to a serving cell is called an uplink component carrier. The downlink component carrier and the uplink component carrier are generically called a component carrier. In FDD, the uplink component carrier and the downlink component carrier correspond to different carrier frequencies. In TDD, the uplink component carrier and the downlink component carrier correspond to the same carrier frequency.

  The terminal device 1 can simultaneously perform transmission and / or reception on a plurality of physical channels in a plurality of serving cells (component carriers). One physical channel is transmitted in one serving cell (component carrier) among a plurality of serving cells (component carriers).

  FIG. 2 is a diagram showing an example of the structure of the MAC layer for the uplink in which carrier aggregation is set in this embodiment. In the uplink in which carrier aggregation is set, there is one independent HARQ entity for each serving cell (uplink component carrier). The HARQ entity manages multiple HARQ processes in parallel. The HARQ process is associated with the HARQ buffer. That is, a HARQ entity is associated with multiple HARQ buffers. The HARQ process stores the MAC layer data in the HARQ buffer. The HARQ process instructs the physical layer to send the MAC layer data.

In the uplink in which carrier aggregation is set, at least one transport block may be generated for each TTI (Transmission Time Interval) for each serving cell. Each transport block and the HARQ retransmissions of that transport block are mapped to one serving cell. The TTI is also called a subframe. The transport block is MAC layer data transmitted by UL-SCH (uplink shared channel).

  In the uplink of the present embodiment, “transport block”, “MAC PDU (Protocol Data Unit)”, “MAC layer data”, “UL-SCH”, “UL-SCH data”, and “uplink data”. Are the same.

  Physical channels and physical signals of this embodiment will be described.

In the uplink wireless communication from the terminal device 1 to the base station device 3, the following uplink physical channels are used. The uplink physical channel is used to transmit the information output from the upper layer.
・ PUCCH (Physical Uplink Control Channel)
・ PUSCH (Physical Uplink Shared Channel)
・ PRACH (Physical Random Access Channel)
PUCCH is used for transmitting uplink control information (Uplink Control Information: UCI). The uplink control information is downlink channel state information (Channel State Information: CSI), and a scheduling request (Scheduling Request: used to request PUSCH (Uplink-Shared Channel: UL-SCH) resources for initial transmission). SR) and HARQ-ACK (Hybrid Automatic Repeat request ACKnowledgement) 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 indicates ACK (acknowledgement) or NACK (negative-acknowledgement). HARQ-ACK is also referred to as ACK / NACK, HARQ feedback, HARQ response, or HARQ control information.

  The scheduling request includes a positive scheduling request or a negative scheduling request. A positive scheduling request indicates requesting UL-SCH resources for initial transmission. A negative scheduling request indicates that it does not request UL-SCH resources for initial transmission.

PUSCH is used for transmitting uplink data (Uplink-Shared Channel: UL-SCH). The PUSCH may also be used to transmit HARQ-ACK and / or channel state information with the uplink data. Also, PUSCH may be used to transmit only channel state information. Also, PUSCH may be used to transmit only HARQ-ACK and channel state information.

Here, the base station apparatus 3 and the terminal apparatus 1 exchange (transmit / receive) a signal in a higher layer. For example, the base station device 3 and the terminal device 1 may transmit and receive RRC signaling in a radio resource control (RRC: Radio Resource Control) layer. Moreover, the base station apparatus 3 and the terminal apparatus 1 may transmit / receive MAC CE in a medium access control (MAC: Medium Access Control) layer. Here, RRC signaling and / or MAC CE are also referred to as higher layer signaling. RRC signaling and / or MAC CE are included in the transport block.

  In the present embodiment, “RRC signaling”, “RRC layer information”, “RRC layer signal”, “RRC layer parameter”, “RRC message”, and “RRC information element” are the same. ..

PUSCH is used to transmit RRC signaling and MAC CE. Here, the RRC signaling transmitted from the base station device 3 may be common signaling to the plurality of terminal devices 1 in the cell. Further, the RRC signaling transmitted from the base station device 3 may be dedicated signaling (also referred to as dedicated signaling) for a certain terminal device 1. That is, the user device specific information (unique to the user device) is transmitted to a certain terminal device 1 using dedicated signaling.

PRACH is used to transmit a random access preamble. The PRACH indicates an initial connection establishment procedure, a handover procedure, a connection re-establishment procedure, synchronization (timing adjustment) for uplink transmission, and a request for PUSCH (UL-SCH) resources. Used for.

The following uplink physical signals are used in uplink wireless communication. The uplink physical signal is not used to transmit the information output from the upper layer, but is used by the physical layer.
・ Uplink Reference Signal (UL RS)
In downlink radio communication from the base station device 3 to the terminal device 1, the following downlink physical channels are used. The downlink physical channel is used to transmit information output from the upper layer.
・ PBCH (Physical Broadcast Channel)
・ PCFICH (Physical Control Format Indicator Channel)
・ PHICH (Physical Hybrid automatic repeat request Indicator Channel)
・ PDCCH (Physical Downlink Control Channel)
・ EPDCCH (Enhanced Physical Downlink Control Channel)
・ PDSCH (Physical Downlink Shared Channel)
・ PMCH (Physical Multicast Channel)
The PBCH is used to broadcast a master information block (MIB, Broadcast Channel: BCH) commonly used by the terminal device 1.

  PCFICH is used to transmit information indicating a region (OFDM symbol) used for transmitting PDCCH.

  The PHICH is used to transmit a HARQ indicator (HARQ feedback, response information) indicating ACK (ACKnowledgement) or NACK (Negative ACKnowledgement) for the uplink data (Uplink Shared Channel: UL-SCH) received by the base station device 3. Be done.

The PDCCH and EPDCCH are used to transmit downlink control information (Downlink Control Information: DCI). In this embodiment, "PDCCH" is used for convenience.
Includes "EPDCCH". The downlink control information is also called a DCI format. The downlink control information transmitted on one PDCCH includes a downlink grant (downlink grant) and HARQ information, or an uplink grant (uplink grant) and HARQ information. The downlink grant is also referred to as downlink assignment or downlink allocation. Downlink assignment and uplink grant are not transmitted together on one PDCCH. The downlink grant and the uplink grant may include HARQ information.

  Downlink assignment is used for scheduling a single PDSCH in a single cell. The downlink assignment is used for scheduling the PDSCH in the same subframe as the subframe in which the downlink grant is transmitted.

  The uplink grant may be used for scheduling a single PUSCH in a single cell. The uplink grant may be used for scheduling a single PUSCH in a subframe after the subframe in which the uplink grant is transmitted.

The HARQ information may include NDI (New Data Indicator) and information for indicating the transport block size. The HARQ information transmitted on the PDCCH together with the downlink assignment also includes information indicating the HARQ process number in the downlink (downlink HARQ process Identifier / Identity, downlink HARQ process number). The HARQ information transmitted on the PDCCH together with the uplink grant regarding asynchronous HARQ may also include information indicating the number of the HARQ process in the uplink (uplink HARQ process Identifier / Identity, uplink HARQ process number). The HARQ information transmitted on the PDCCH together with the uplink grant regarding the synchronous HARQ may not include information indicating the HARQ process number in the uplink (uplink HARQ process Identifier / Identity, uplink HARQ process number).

  NDI indicates initial transmission or retransmission. The HARQ entity triggers an initial transmission for a HARQ process if the NDI provided by the HARQ information is toggled compared to the value of NDI for the previous transmission of the HARQ process. Instruct them to do so. The HARQ entity triggers a retransmission for a HARQ process if the NDI provided by the HARQ information is not toggled compared to the value of the NDI for the previous transmission of the HARQ process. Instruct them to do so. It should be noted that the HARQ process may determine whether NDI is toggled.

  The HARQ entity specifies the uplink grant and the HARQ process to which the HARQ information corresponds, and passes the uplink grant and the HARQ information to the specified HARQ process. The HARQ process stores the uplink grant passed from the HARQ entity and the HARQ information.

  The CRC (Cyclic Redundancy Check) parity bit added to the downlink control information transmitted by one PDCCH is C-RNTI (Cell-Radio Network Temporary Identifier), SPS (Semi Persistent Scheduling) C-RNTI, or Temporary. It is scrambled with C-RNTI. C-RNTI and SPS C-RNTI are identifiers for identifying a terminal device in a cell. The Temporary C-RNTI is an identifier for identifying the terminal device 1 which has transmitted the random access preamble during the contention based random access procedure.

  C-RNTI and Temporary C-RNTI are used to control PDSCH transmission or PUSCH transmission in a single subframe. The SPS C-RNTI is used to periodically allocate PDSCH or PUSCH resources.

  Hereinafter, unless otherwise specified, the CRC parity bits added to the downlink control information in this embodiment are scrambled by C-RNTI.

PDSCH is used for transmitting downlink data (Downlink Shared Channel: DL-SCH).

  PMCH is used to transmit multicast data (Multicast Channel: MCH).

The following downlink physical signals are used in downlink radio communication. The downlink physical signal is not used to transmit the information output from the upper layer, but is used by the physical layer.
・ Synchronization signal (SS)
・ Downlink Reference Signal (DL RS)
The synchronization signal is used by the terminal device 1 to synchronize the downlink frequency domain and time domain. In the TDD method, the synchronization signal is arranged in subframes 0, 1, 5, and 6 in the radio frame. In the FDD system, the synchronization signal is placed in subframes 0 and 5 in the radio frame.

  The downlink reference signal is used by the terminal device 1 to perform channel correction of the downlink physical channel. The downlink reference signal is used by the terminal device 1 to calculate downlink channel state information.

In this embodiment, the following five types of downlink reference signals are used.
・ CRS (Cell-specific Reference Signal)
URS (UE-specific Reference Signal) related to PDSCH
DMRS (Demodulation Reference Signal) related to EPDCCH
・ NZP CSI-RS (Non-Zero Power Chanel State Information-Reference Signal)
・ ZP CSI-RS (Zero Power Chanel State Information-Reference Signal)
・ MBSFN RS (Multimedia Broadcast and Multicast Service over Single Frequency Network Reference signal)
・ PRS (Positioning Reference Signal)
The downlink physical channel and the downlink physical signal are collectively referred to as a downlink signal. The uplink physical channel and the uplink physical signal are collectively referred to as an uplink signal. The downlink physical channel and the uplink physical channel are generically called a physical channel. The downlink physical signal and the uplink physical signal are collectively referred to as a physical signal.

BCH, MCH, UL-SCH and DL-SCH are transport channels. A channel used in a MAC (Medium Access Control) layer is called a transport channel. The transport channel unit used in the MAC layer is also called a transport block (transport block: TB) or a MAC PDU (Protocol Data Unit). HARQ (Hybrid Automatic Repeat reQuest) is controlled for each transport block in the MAC layer. The transport block is a unit of data delivered by the MAC layer to the physical layer. In the physical layer, transport blocks are mapped to codewords, and an encoding process is performed for each codeword.

  The structure of the radio frame of this embodiment will be described.

  In this embodiment, two radio frame structures are supported. The two radio frame structures are frame structure type 1 and frame structure type 2. Frame structure type 1 is applicable to FDD. Frame structure type 2 is applicable to TDD.

  FIG. 3 is a diagram showing a schematic configuration of the radio frame of the present embodiment. In FIG. 3, the horizontal axis is the time axis. In addition, each of the type 1 and type 2 radio frames has a length of 10 ms and is defined by 10 subframes. Each subframe is 1 ms long and is defined by two consecutive slots. Each of the slots is 0.5 ms long. The i-th subframe in the radio frame is composed of the (2 × i) -th slot and the (2 × i + 1) -th slot.

For frame structure type 2, the following three types of subframes are defined.
-Downlink subframe-Uplink subframe-Special subframe A downlink subframe is a subframe reserved for downlink transmission. The uplink subframe is a subframe reserved for uplink transmission. The special subframe is composed of three fields. The three fields are DwPTS (Downlink Pilot Time Slot), GP (Guard Period), and UpPTS (Uplink Pilot Time Slot). The total length of DwPTS, GP, and UpPTS is 1 ms. DwPTS is a field reserved for downlink transmission. UpPTS is a field reserved for uplink transmission. GP is a field in which neither downlink transmission nor uplink transmission is performed. The special subframe may be composed of only DwPTS and GP, or may be composed of only GP and UpPTS.

A radio frame of frame structure type 2 is composed of at least a downlink subframe, an uplink subframe, and a special subframe. The structure of the radio frame of frame structure type 2 is indicated by UL-DL configuration (uplink-downlink configuration). The terminal device 1 receives the information indicating the UL-DL setting from the base station device 3. FIG. 4 is a table showing an example of UL-DL settings in the present embodiment. In FIG. 4, D indicates a downlink subframe, U indicates an uplink subframe, and S indicates a special subframe.

  Hereinafter, PDCCH monitoring will be described.

Monitoring means trying to decode the PDCCH according to a certain DCI format. The PDCCH is transmitted in the PDCCH candidate. The terminal device 1 monitors a set of PDCCH candidates (candidate) in the serving cell. A set of PDCCH candidates is called a search space. The search space includes at least a common search space (Common Search Space) and a UE-specific search space (UE-specific Search Space). The UE-specific search space is at least derived from the value of C-RNTI set by the terminal device 1. That is, the UE-specific search space is individually derived for each terminal device 1. The common search space is a common search space among a plurality of terminal devices 1, and has a predetermined index CCE (Control Channel Element).
Composed of. The CCE is composed of a plurality of resource elements.

  The DCI format type will be described below.

The DCI format includes DCI format 0 and DCI format 0C. DCI format 0 and DCI format 0C include an uplink grant and are used for PUSCH scheduling in one cell. The uplink grant included in DCI format 0 and DCI format 0C is
It is also called an uplink grant included in the PDCCH. DCI format 0 may be used for synchronous HARQ and asynchronous HARQ. DCI format 0C may be used for asynchronous HARQ. DCI format 0C is not used for synchronous HARQ.

  The terminal device 1 in which the RRC layer parameter PUSCH Enh-Configuration for the serving cell is not set may decode the PDCCH including the DCI format 0 in the CSS and the USS in the serving cell. The terminal device 1 in which the RRC layer parameter PUSCHEnh-Configuration for the serving cell is set may decode the PDCCH including the DCI format 0 in the CSS in the serving cell, and the PDCCH including the DCI format 0C in the USS in the serving cell. May be decoded. The terminal device 1 in which the RPU layer parameter PUSCH Enh-Configuration for the serving cell is set may not decode the PDCCH including the DCI format 0 in the USS in the serving cell.

  When the RRC layer parameter PUSCH Enh-Configuration for the serving cell is not set, synchronous HARQ may be applied to the uplink of the serving cell. When the RRC layer parameter PUSCH Enh-Configuration for the serving cell is set, asynchronous HARQ may be applied to the uplink of the serving cell. Setting the RRC layer parameter PUSCHEnh-Configuration is also referred to as setting the PUSCH enhancement mode. The fact that the RRC layer parameter PUSCHEnh-Configuration is not set is also referred to as that the PUSCH enhancement mode is not set. The terminal device 1 may set the parameter PUSCHEnh-Configuration of the RRC layer based on the information of the RRC layer received from the base station device 3. The terminal device 1 may release the parameter PUSCHEnh-Configuration of the RRC layer based on the RRC layer information received from the base station device 3.

The DCI format 0 does not include the “Repetition number” field and the “HARQ process number” field. The terminal device 1 executes the transmission of the PUSCH in one subframe based on the detection of the PDCCH including the DCI format 0.

The DCI format 0C includes a "Repetition number" field and a "HARQ process number" field. The terminal device 1 in which the RPU layer parameter PUSCHEnh-Configuration for the serving cell is set executes the transmission of the PUSCH in the subframe set based on the detection of the PDCCH including the DCI format 0C. The set of subframes includes one or a plurality of subframes. The number of subframes included in the set of subframes is given by the "Repetition number" field. The PUSCH transmission scheduled by the DCI format 0C may be repeatedly transmitted in a plurality of subframes. The PUSCH transmission scheduled by DCI format 0C may be transmitted in one subframe. The “HARQ process number” field is used by the HARQ entity to identify the HARQ process.

The uplink grant included in the random access response is called a random access response grant. The random access response grant is used for PUSCH scheduling. Contention-based random access procedure (contenti
The uplink grant included in the random access response corresponding to the “on based random access procedure” includes a “Repetition number” field, and
It does not include the "HARQ process number" field. The uplink grant included in the random access response corresponding to the non-contention based random access procedure does not include the “HARQ process number” field. A random access response corresponding to a non-contention based random access procedure, which is included in a random access response to the terminal device 1 in which the RPU layer parameter PUSCH Enh-Configuration is not set. The grant does not include a "Repetition number" field.
The random access response corresponding to the non-contention based random access procedure, which is included in the random access response to the terminal device 1 in which the RRC layer parameter PUSCHEnh-Configuration is set Grant is "Repetition nu"
mber "field.

  The random access procedure will be described below.

  In this embodiment, a random access procedure may be executed in the primary cell. However, only one random access procedure is executed at any point in the time domain. That is, multiple random access procedures are not executed simultaneously.

  In this embodiment, a contention based random access procedure and a non-contention based random access procedure may be executed in the primary cell.

  The random access preamble may be transmitted on the PRACH in the primary cell. The terminal device 1 receives the information (RRC message) regarding the random access procedure in the primary cell from the base station device 3. The information on the random access procedure in the primary cell includes information indicating the set of PRACH resources in the primary cell.

  In the case of the contention based random access procedure, the index of the random access preamble is selected by the terminal device 1 itself. In the case of the non-contention based random access procedure, the terminal device 1 selects the index of the random access preamble based on the information received from the base station device 3. Here, the information received from the base station device 3 by the terminal device 1 may be included in the PDCCH. When all the bit values of the information received from the base station device 3 are 0, the terminal device 1 executes the contention-based random access procedure, and the terminal device 1 itself selects the index of the random access preamble.

  The random access response for the primary cell is transmitted on PDSCH in the primary cell. The PDSCH corresponds to the PDCCH including RA-RNTI. The random access response includes an uplink grant field mapped to the uplink grant, and a Temporary C-RNTI field mapped to information for indicating the Temporary C-RNTI.

When the received random access response includes a random access preamble identifier corresponding to the transmitted random access preamble and the terminal device 1 selects the random access preamble based on the information received from the base station device 3, The device 1 considers that the non-contention based random access procedure has been successfully completed, and transmits the PUSCH based on the uplink grant included in the random access response.

  When the random access preamble identifier corresponding to the transmitted random access preamble is included in the received random access response and the random access preamble is selected by the terminal device 1 itself, in the random access response that receives the Temporary C-RNTI. The value of the included Temporary C-RNTI field is set, and the random access message 3 is transmitted by PUSCH based on the uplink grant included in the random access response.

  The PUSCH corresponding to the uplink grant included in the random access response is transmitted in the serving cell in which the corresponding preamble is transmitted on the PRACH.

  When the Temporary C-RNTI is not set, the PUSCH corresponding to the uplink grant included in the random access response and the PUSCH retransmission of the same transport block are scrambled based on the C-RNTI.

  When the Temporary C-RNTI is set, the PUSCH corresponding to the uplink grant included in the random access response and the PUSCH retransmission of the same transport block are scrambled based on the Temporary C-RNTI.

When the Temporary C-RNTI is set, the PUSCH retransmission of the transport block transmitted by the PUSCH corresponding to the uplink grant included in the random access response is added with the CRC parity bit scrambled by the Temporary C-RNTI. Scheduled according to DCI format 0. The DCI format 0 is a PD in the common search space.
Sent on CCH.

  Hereinafter, synchronous HARQ in the uplink will be described.

  In synchronous HARQ, the HARQ process corresponding to the uplink grant is associated with the subframe in which the uplink grant is received and / or the subframe in which the PUSCH (UL-SCH) corresponding to the uplink grant is transmitted. In the synchronous HARQ, the terminal device 1 uses the HARQ process corresponding to the uplink grant, the subframe in which the uplink grant is received, and / or the subframe in which the PUSCH (UL-SCH) corresponding to the uplink grant is transmitted. Derive from That is, in synchronous HARQ, the HARQ entity may specify the HARQ process to which the uplink grant corresponds without using the information included in the uplink grant.

  FIG. 5 is a diagram showing an example of synchronous HARQ in the present embodiment. In FIG. 5, one subframe corresponds to one HARQ process. In FIG. 5, the numbers in the squares indicate the corresponding HARQ process numbers. In synchronous HARQ, the HARQ entity derives a HARQ process from a subframe in which UL-SCH data in the MAC layer is transmitted or a subframe in which DCI format 0 corresponding to UL-SCH data in the MAC layer is detected. Be done.

  In FIG. 5, the subframe in which the data of the MAC layer corresponding to the uplink grant is transmitted is derived from the subframe in which the uplink grant is received. For example, UL-SCH data in the MAC layer corresponding to the uplink grant may be transmitted on the PUSCH in a subframe four frames after the subframe in which the uplink grant is received.

  In synchronous HARQ, a HARQ indicator is transmitted on PHICH in response to an uplink transmission. The correspondence between the subframe in which the uplink transmission is performed and the subframe in which the corresponding PHICH is transmitted is predetermined. For example, in a subframe that is four subframes after the subframe in which the MAC layer data is transmitted by PUSCH, the HARQ indicator for the MAC layer data is transmitted by PHICH. Also, for example, in the subframe four frames after the subframe in which NACK is received in PHICH, the data of the MAC layer is retransmitted by PUSCH.

  Hereinafter, asynchronous HARQ in the uplink will be described.

  FIG. 6 is a diagram showing an example of asynchronous HARQ in the present embodiment. In FIG. 6, one subframe corresponds to one HARQ process. In FIG. 6, the numbers in the squares indicate the corresponding HARQ process numbers. In the case of asynchronous HARQ, when an uplink grant (DCI format 0C) is included in the PDCCH mapped in the UE-specific search space, the HARQ entity derives the HARQ process from the "HARQ process number" field. In the asynchronous HARQ, when the uplink grant (DCI format 0) is included in the PDCCH mapped in the common search space, the HARQ entity may use the HARQ process with a specific number. In asynchronous HARQ, when the uplink grant is included in the random access response, the HARQ entity may use a HARQ process with a specific number. The specific number may be zero. The specific number may be a predetermined number.

  In asynchronous HARQ, the HARQ indicator is not transmitted on PHICH in response to the uplink transmission. That is, in asynchronous HARQ, retransmission of MAC layer data is always scheduled via the PDCCH. In FIG. 6, the subframe in which the MAC layer data corresponding to the uplink grant is transmitted is derived from the subframe in which the uplink grant is received. For example, in a subframe that is four subframes after the subframe in which the uplink grant is received, the MAC layer data corresponding to the uplink grant may be transmitted by PUSCH.

  That is, in the terminal device 1, (1) the type of search space to which the PDCCH including the uplink grant is mapped, (2) whether the uplink grant is included in the random access response or the PDCCH, and / or ( 3) The HARQ process to which the uplink grant corresponds may be specified at least based on whether or not the RRC layer parameter PUSCHEnh-Configuration is set.

  Hereinafter, PDCCH decoding for HARQ retransmission will be described.

FIG. 7 is a diagram illustrating pseudo code for decoding PDCCH for HARQ retransmission. In FIG. 7, PDCCH is a PDCCH including an uplink grant. The terminal device 1 considers that the PDCCH is generated in the specific search space means that the terminal device 1 attempts to decode the PDCCH in the specific search space, and the base station device 1 transmits the PDCCH in the specific search space. Means When the terminal device 1 considers that the PDCCH occurs in the common search space or the UE-specific search space, the terminal device 1 attempts to decode the PDCCH in the common search space and the UE-specific search space, and the base station device 1 This means transmitting the PDCCH in any of the plurality of PDCCH candidates corresponding to the common search space and the UE-specific search space.

  PUSCH initial transmission for the transport block means initial transmission of the transport block using the PUSCH. PUSCH retransmission for a transport block means to retransmit a transport block using PUSCH.

  The terminal device 1 and the base station device 3 are (1) a type of random access procedure corresponding to a random access response grant including an uplink grant for PUSCH initial transmission for a transport block, (2) uplink The type of search space to which the PDCCH including the grant is mapped, (3) whether the uplink grant is included in the random access response or the PDCCH, and / or (4) the RRC layer parameter PUSCHEnh-Configuration is set. It may be determined which of the processing A to the processing C is to be executed based on at least whether the processing is performed.

  That is, in the terminal device 1, (1) the type of random access procedure corresponding to the random access response grant including the uplink grant for the PUSCH initial transmission for the transport block, (2) the PDCCH including the uplink grant is The type of search space to be mapped, (3) whether the uplink grant is included in the random access response or the PDCCH, and / or (4) whether the RRC layer parameter PUSCHEnh-Configuration is set, At least based on which type of search space to try to decode the PDCCH for PUSCH retransmission of the transport block may be determined.

  That is, the base station device 3 includes (1) a type of random access procedure corresponding to a random access response grant including an uplink grant for PUSCH initial transmission for a transport block, and (2) a PDCCH including an uplink grant. The type of search space to which is mapped, (3) whether the uplink grant is included in the random access response or the PDCCH, and / or (4) whether the RRC layer parameter PUSCHEnh-Configuration is set. , It may be determined based on at least which type of search space the PDCCH for PUSCH retransmission of the transport block is transmitted.

  When the condition A is satisfied, the terminal device 1 and the base station device 3 execute the process A. When the condition B is satisfied and at least one of the condition C and the condition D is satisfied, the terminal device 1 and the base station device 3 execute the process B. When the condition E is satisfied and at least one of the condition F and the condition G is satisfied, the terminal device 1 and the base station device 3 execute the process C. When the condition E and the condition H are satisfied, the terminal device 1 and the base station device 3 execute the process A.

  Process A is that the terminal device 1 considers that the PDCCH for PUSCH retransmission of the transport block occurs in the common search space. The process B is that the terminal device 1 considers that the PDCCH for PUSCH retransmission of the transport block occurs in the common search space or the UE-specific search space. The process C is that the terminal device 1 considers that the PDCCH for PUSCH retransmission of the transport block occurs in the UE-specific search space.

  Condition A is that the PUSCH initial transmission for the transport block is scheduled by the uplink grant included in the random access response corresponding to the contention based random access procedure. The condition A may be that the uplink grant for PUSCH initial transmission for the transport block is included in the random access response corresponding to the contention-based random access procedure.

  The condition B is that the parameter PUSCHEnh-Configuration of the RRC layer is not set for the terminal device 1. Condition C is that the PDCCH for PUSCH initial transmission for the transport block has been decoded. The conditions D and G are that the PUSCH initial transmission for the transport block is scheduled by the uplink grant included in the random access response grant corresponding to the non-contention based random access procedure. The condition E is that the RPU layer parameter PUSCHEnh-Configuration is set for the terminal device 1. Condition F is that the PDCCH for PUSCH initial transmission for the transport block has been decoded in the UE-specific search space. Condition H is that the PDCCH for the PUSCH initial transmission for the transport block has been decoded in the common search space.

  The configuration of the device according to this embodiment will be described below.

FIG. 8 is a schematic block diagram showing the configuration of the terminal device 1 of this embodiment. As illustrated, the terminal device 1 is configured to include a wireless transmission / reception unit 10 and an upper layer processing unit 14. The wireless transmission / reception unit 10 includes an antenna unit 11, an RF (Radio Frequency) unit 12, and a baseband unit 13. The upper layer processing unit 14 includes a medium access control layer processing unit 15 and a radio resource control layer processing unit 16. The wireless transmission / reception unit 10 is also referred to as a transmission unit, a reception unit, or a physical layer processing unit.

The upper layer processing unit 14 outputs the uplink data (transport block) generated by the user's operation or the like to the wireless transmission / reception unit 10. The upper layer processing unit 14 is a medium access control (MAC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a radio resource control (Radio). Resource Control (RRC) layer processing.

  The medium access control layer processing unit 15 included in the upper layer processing unit 14 processes the medium access control layer. The medium access control layer processing unit 15 controls HARQ based on various setting information / parameters managed by the radio resource control layer processing unit 16. The medium access control layer processing unit 15 manages a plurality of HARQ entities, a plurality of HARQ processes, and a plurality of HARQ buffers.

  The radio resource control layer processing unit 16 included in the upper layer processing unit 14 performs processing of the radio resource control layer. 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 the RRC layer signal received from the base station device 3. That is, the radio resource control layer processing unit 16 sets various setting information / parameters based on the information indicating various setting information / parameters received from the base station device 3.

  The wireless transmission / reception unit 10 performs physical layer processing such as modulation, demodulation, encoding, and decoding. The wireless transmission / reception unit 10 separates, demodulates, and decodes the signal received from the base station device 3, and outputs the decoded information to the upper layer processing unit 14. The wireless transmission / reception unit 10 generates a transmission signal by modulating and encoding data and transmits the transmission signal to the base station device 3.

The RF unit 12 converts a signal received via the antenna unit 11 into a baseband signal by quadrature demodulation (down covert) and removes unnecessary frequency components. RF
The 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 a portion corresponding to CP (Cyclic Prefix) from the converted digital signal, performs Fast Fourier Transform (FFT) on the signal from which CP is removed, and outputs a signal in the frequency domain. Extract.

  The baseband unit 13 performs an Inverse Fast Fourier Transform (IFFT) on the data to generate an SC-FDMA symbol, adds a CP to the generated SC-FDMA symbol, and outputs a baseband digital signal. Generate and convert baseband digital signals to analog signals. The baseband unit 13 outputs the converted analog signal to the RF unit 12.

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

  FIG. 9 is a schematic block diagram showing the configuration of the base station device 3 of this embodiment. As illustrated, the base station device 3 is configured to include a wireless transmission / reception unit 30 and an upper layer processing unit 34. The wireless transmission / reception 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 wireless transmission / reception unit 30 is also referred to as a transmission unit, a reception unit, or a physical layer processing unit.

  The upper layer processing unit 34 includes a medium access control (MAC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a radio resource control (Radio). Resource Control (RRC) layer processing.

  The medium access control layer processing unit 35 included in the upper layer processing unit 34 performs processing of the medium access control layer. The medium access control layer processing unit 15 controls HARQ based on various setting information / parameters managed by the radio resource control layer processing unit 16. The medium access control layer processing unit 15 generates ACK / NACK and HARQ information for uplink data (UL-SCH). The ACK / NACK and HARQ information for the uplink data (UL-SCH) are transmitted to the terminal device 1 on the PHICH or PDCCH.

The radio resource control layer processing unit 36 included in the upper layer processing unit 34 performs processing of the radio resource control layer. The radio resource control layer processing unit 36 generates downlink data (transport block) arranged in the physical downlink shared channel, system information, RRC message, MAC CE (Control Element), or the like, or acquires from the upper node. , To the wireless transmission / reception unit 30. Further, the radio resource control layer processing unit 36 manages various setting information / parameters of each terminal device 1. The radio resource control layer processing unit 36 may set various setting information / parameters for each terminal device 1 via a signal of an upper layer. That is, the radio resource control layer processing unit 36 transmits / notifies information indicating various setting information / parameters.

  The function of the wireless transmission / reception unit 30 is the same as that of the wireless transmission / reception unit 10, and the description thereof is omitted.

  Hereinafter, various aspects of the terminal device and the base station device in the present embodiment will be described.

  (1) A first aspect of the present embodiment is a terminal device, which includes a transmitter 10 that performs initial transmission of a transport block and a random number that includes an uplink grant for the initial transmission of the transport block. The receiving unit 10 selects a search space based on the type of random access procedure to which the access response corresponds, and attempts to decode the PDCCH for retransmission of the transport block in the selected search space.

  (2) A second aspect of the present embodiment is a base station apparatus, which includes a receiving unit 30 that receives initial transmission of a transport block, and an uplink grant for the initial transmission of the transport block. A transmitter 30 that selects a search space based on the type of random access procedure to which the random access response corresponds, and transmits a PDCCH for retransmission of the transport block in the selected search space.

  (3) In the first and second aspects of the present embodiment, the initial transmission is performed via PUSCH, and the retransmission is performed via PUSCH.

  (4) In the first and second aspects of this embodiment, the search space includes a common search space and a UE-specific search space.

  (5) In the first and second aspects of this embodiment, the types of the random access procedure include a contention-based random access procedure and a non-contention-based random access procedure.

  (6) In the first and second aspects of this embodiment, the PDCCH includes an uplink grant for retransmission of the transport block.

  (7) In the first and second aspects of the present embodiment, the RPU layer parameter PUSCHEnh-Configuration is set for the terminal device.

  (8) In the first and second aspects of the present embodiment, the RPU layer parameter PUSCHEnh-Configuration corresponds to one serving cell, and the RRC layer parameter PUSCHEnh-Configuration is set for the terminal device. If the asynchronous HARQ is applied to the uplink of the serving cell and the parameter PUSCHEnh-Configuration of the RRC layer is not set for the terminal device, the synchronous HARQ is applied to the uplink of the serving cell. To be done.

(9) In the first aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal device, and the uplink grant for the initial transmission of the transport block is If the included random access response corresponds to the non-contention based random access procedure, the receiver 10 attempts to decode the PDCCH for the retransmission of the transport block in the UE-specific search space. Here, the receiving unit 10 does not try to decode the PDCCH in the common search space.

  (10) In the first aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal device, and the uplink grant for the initial transmission of the transport block is If the included random access response corresponds to the contention-based random access procedure, the receiver 10 attempts to decode the PDCCH for the retransmission of the transport block in the common search space. Here, the receiving unit 10 does not try to decode the PDCCH in the UE-specific search space.

  (11) In the first aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is not set for the terminal device, and the uplink grant for the initial transmission of the transport block is performed. When the random access response including is corresponding to the non-contention based random access procedure, the receiving unit 10 for the retransmission of the transport block in the UE-specific search space and the common search space. Attempts to decode the PDCCH.

  (12) In the first aspect of the present embodiment, the RPU layer parameter PUSCHEnh-Configuration is not set for the terminal device, and the uplink grant for the initial transmission of the transport block is performed. When the random access response including the packet corresponds to the contention-based random access procedure, the receiving unit 10 attempts to decode the PDCCH for the retransmission of the transport block in the common search space. Here, the receiving unit 10 does not try to decode the PDCCH in the UE-specific search space.

  (13) In the second aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal device, and the uplink grant for the initial transmission of the transport block is If the included random access response corresponds to the non-contention based random access procedure, the transmitter transmits the PDCCH for the retransmission of the transport block in the UE-specific search space.

  (14) In the second aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal device, and the uplink grant for the initial transmission of the transport block is If the included random access response corresponds to the contention-based random access procedure, the transmitter transmits the PDCCH for the retransmission of the transport block in the common search space.

  (15) In the second aspect of the present embodiment, the RRC layer parameter PUSCHEnh-Configuration is not set for the terminal device, and the uplink grant for the initial transmission of the transport block is performed. If the random access response including the corresponding to the non-contention based random access procedure, the transmitter, the transport unit in any of the plurality of PDCCH candidates corresponding to the UE-specific search space and the common search space. Transmit the PDCCH for the retransmission of blocks.

(16) In the second aspect of the present embodiment, the RPU layer parameter PUSCHEnh-Configuration is not set for the terminal device, and the uplink grant for the initial transmission of the transport block is performed. If the random access response including is corresponding to the contention-based random access procedure, the transmitting unit transmits the PDCCH for the retransmission of the transport block in the common search space.

  (17) A third aspect of the present embodiment is a terminal device, which includes a receiving unit 10 that decodes a PDCCH including an uplink grant, and a medium access control layer processing unit 15 that manages a plurality of HARQ processes. , The HARQ process corresponding to the uplink grant is determined based at least on the search space in which the PDCCH is decoded.

  (18) In the third aspect of the present embodiment, when the PDCCH is decoded in a common search space, the uplink grant corresponds to a HARQ process with a predetermined number.

  (19) A fourth aspect of the present embodiment is a base station apparatus, which includes a transmission unit 30 that transmits a PDCCH including an uplink grant and a medium access control layer processing unit 35 that manages a plurality of HARQ processes. The HARQ process corresponding to the uplink grant is determined based at least on the search space in which the PDCCH is transmitted.

  (20) In the fifth aspect of the present embodiment, when the PDCCH is transmitted in the common search space, the uplink grant corresponds to the HARQ process with a predetermined number.

  As a result, the terminal device 1 can efficiently communicate with the base station device 3.

A program that operates in the base station device 3 and the terminal device 1 according to the present invention is a program that controls a CPU (Central Processing Unit) or the like (makes a computer function so as to realize the functions of the above-described embodiments according to the present invention. Program). Information handled by these devices is temporarily stored in a RAM (Random Access Memory) during the processing, and thereafter, various ROMs such as a flash ROM (Read Only Memory) and an HD.
The data is stored in a D (Hard Disk Drive), and is read, modified, and written by the CPU as needed.

  The terminal device 1 and a part of the base station device 3 in the above-described embodiment may be realized by a computer. In that case, the program for realizing the control function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read by a computer system and executed.

  The “computer system” mentioned here is a computer system built in the terminal device 1 or the base station device 3, and includes an OS and hardware such as peripheral devices. Further, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system.

Furthermore, the "computer-readable recording medium" means a program that dynamically holds a program for a short time, such as a communication line when transmitting the program through a network such as the Internet or a communication line such as a telephone line. In such a case, a volatile memory inside the computer system serving as a server or a client that holds the program for a certain period of time may be included. Further, the above-mentioned program may be one for realizing a part of the above-mentioned functions, and may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

  In addition, the base station device 3 in the above-described embodiment can also be realized as an aggregate (device group) including a plurality of devices. Each of the devices forming the device group may include some or all of the functions or functional blocks of the base station device 3 according to the above-described embodiment. It suffices for the device group to have one type of each function or each functional block of the base station device 3. Further, the terminal device 1 according to the above-described embodiment can also communicate with the base station device as an aggregate.

  In addition, the base station device 3 in the above-described embodiment may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network). Further, the base station device 3 in the above-described embodiment may have some or all of the functions of the upper node with respect to the eNodeB.

  In addition, part or all of the terminal device 1 and the base station device 3 in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit, or may be realized as a chip set. Each functional block of the terminal device 1 and the base station device 3 may be individually made into a chip, or a part or all of them may be integrated and made into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when a technique for forming an integrated circuit that replaces LSI appears due to the progress of semiconductor technology, it is possible to use an integrated circuit according to the technique.

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

  Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the scope of the present invention. The present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Be done. Further, it also includes a configuration in which elements that are described in each of the above-described embodiments and that have similar effects are replaced with each other.

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

Claims (8)

A transmitter that performs the initial transmission of the transport block,
Select a search space based on the type of random access procedure to which the random access response including the uplink grant for the initial transmission of the transport block corresponds, and retransmit the transport block in the selected search space. And a receiving unit that attempts to decode the PDCCH for. A receiver for receiving the initial transmission of the transport block,
Select a search space based on the type of random access procedure to which the random access response including the uplink grant for the initial transmission of the transport block corresponds, and retransmit the transport block in the selected search space. And a transmitter that transmits a PDCCH for the base station apparatus. A communication method used for a terminal device,
Perform the initial transmission of the transport block,
Select a search space based on the type of random access procedure to which the random access response including the uplink grant for the initial transmission of the transport block corresponds, and retransmit the transport block in the selected search space. Method for attempting to decode PDCCH for communication. A communication method used for a base station device, comprising:
Receive the initial transmission of the transport block,
Select a search space based on the type of random access procedure to which the random access response including the uplink grant for the initial transmission of the transport block corresponds, and retransmit the transport block in the selected search space. Communication method for transmitting PDCCH for communication. A receiver for decoding the PDCCH including the uplink grant,
A medium access control layer processing unit that manages a plurality of HARQ processes,
The terminal device in which the HARQ process corresponding to the uplink grant is determined based at least on the search space in which the PDCCH is decoded. The terminal device according to claim 5, wherein when the PDCCH is decoded in a common search space, the uplink grant corresponds to a HARQ process having a predetermined number. A transmission unit for transmitting a PDCCH including an uplink grant,
A medium access control layer processing unit that manages a plurality of HARQ processes,
The HARQ process corresponding to the uplink grant is determined based on at least the search space in which the PDCCH is transmitted. The base station apparatus according to claim 7, wherein when the PDCCH is transmitted in a common search space, the uplink grant corresponds to a HARQ process having a predetermined number.

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