WO2018163907A1 - Terminal device, base station device, communication method, and integrated circuit - Google Patents

Abstract

This base station device is provided with: a receiving unit which receives an initial transmission of a transport block; and a transmitting unit which selects a search space on the basis of the type of a random access procedure to which a random access response containing an uplink grant for the initial transmission of the transport block corresponds, and which transmits a PDCCH for retransmitting the transport block in the selected search space.

Description

TERMINAL DEVICE, BASE STATION DEVICE, COMMUNICATION METHOD, AND INTEGRATED CIRCUIT

The present invention relates to a terminal device, a base station device, a communication method, and an integrated circuit.
This application claims priority on Japanese Patent Application No. 2017-045847 filed in Japan on March 10, 2017, the contents of which are incorporated herein by reference.

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 studied in the 3rd Generation Partnership Project (3rd Generation Partnership Project: 3GPP). A base station apparatus is also called eNodeB (evolved | NodeB) or gNodeB. The terminal device is also referred to as UE (User Equipment). This is a cellular communication system in which a plurality of areas covered by a base station apparatus are arranged in a cellular shape. A single base station apparatus may manage a plurality of cells.

In the MAC (Medium Access Control) layer, the HARQ (Hybrid Automatic Repeat Request) functionality is provided. The HARQ function in the downlink has the characteristics of asynchronous HARQ, and the HARQ function in the uplink has the characteristics of synchronous HARQ (Non-Patent Document 1). In 3GPP, introduction of asynchronous HARQ in the uplink has been studied (Non-Patent Document 2).

One embodiment of the present invention has been made in view of the above points, and an object thereof is 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 used for the base station device, a base station device communicating with the terminal device, a communication method used for the base station device, and an integrated circuit mounted on the base station device.

(1) In order to achieve the above object, the aspect of the present invention takes the following measures. That is, the first aspect of the present invention is a terminal device, a transmission unit that performs initial transmission of a transport block, and a random access response including an uplink grant for the initial transmission of the transport block A receiver that selects a search space based on the type of the corresponding random access procedure and attempts 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, wherein a reception unit that receives an initial transmission of a transport block and a random number including an uplink grant for the initial transmission of the transport block are included. A transmission unit that selects a search space based on a type of random access procedure corresponding to the access response, and transmits 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 for a terminal apparatus, 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 decoding of the PDCCH for retransmission of the transport block is attempted 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 A search space is selected based on the type of random access procedure to which the random access response corresponds, and a 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, comprising: 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 to which the uplink grant corresponds is determined based on at least the search space in which the PDCCH is decoded.

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

According to one aspect of 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 | surface which shows an example of UL-DL setting in this embodiment. It is a figure which shows an example of synchronous HARQ in this embodiment. It is a figure which shows an example of asynchronous HARQ in this embodiment. It is a figure which shows the pseudo code regarding the decoding of PDCCH for retransmission of HARQ. 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 the wireless communication system of the present embodiment. In FIG. 1, the radio communication system includes terminal apparatuses 1A to 1C and a base station apparatus 3. Hereinafter, the terminal devices 1A to 1C are referred to as the terminal device 1.

Hereafter, carrier aggregation will be described.

In the present embodiment, the terminal device 1 is set with one or a plurality of 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. One aspect of the present invention may be applied to each of a plurality of serving cells set for the terminal device 1. In addition, an aspect of the present invention may be applied to some of the set serving cells. Further, one aspect of the present invention may be applied to each of a plurality of set serving cell groups. In addition, an aspect of the present invention may be applied to a part of the set groups of a plurality of serving cells. In carrier aggregation, a plurality of set serving cells are also referred to as aggregated serving cells. Hereinafter, unless explicitly stated, the present embodiment is applied to a primary cell or one serving cell.

In the wireless communication system of the present embodiment, TDD (Time Division Duplex) and / or FDD (Frequency Division Duplex) are applied. In the 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. In the case of cell aggregation, a serving cell to which TDD is applied and a serving cell to which FDD is applied may be aggregated.

The set one or more serving cells include one primary cell and zero or more secondary cells. The primary cell is a cell in which an initial connection establishment (initial connection establishment) procedure has been performed, a cell that has started a connection 確立 re-establishment procedure, or a cell designated as a primary cell in a handover procedure. A secondary cell may be set / added when an RRC (Radio Resource Control) connection is established or later.

In the downlink, a carrier corresponding to a serving cell is referred to as a downlink component carrier. In the uplink, a carrier corresponding to a serving cell is referred to as an uplink component carrier. The downlink component carrier and the uplink component carrier are collectively referred to as 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 perform transmission and / or reception on a plurality of physical channels simultaneously 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 illustrating an example of the structure of the MAC layer for the uplink in which carrier aggregation is set in the present embodiment. In the uplink in which carrier aggregation is set, there is one independent HARQ entity (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, the 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 transmit the MAC layer data.

In the uplink in which carrier aggregation is set, at least one transport block may be generated for each serving cell for each TTI (Transmission Time Interval). Each transport block and the HARQ retransmissions for that transport block are mapped to one serving cell. TTI is also referred to as a subframe. The transport block is data of the MAC layer 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” "Shall be the same.

The physical channel and physical signal of this embodiment will be described.

In 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 for transmitting information output from an upper layer.
-PUCCH (Physical Uplink Control Channel)
・ PUSCH (Physical Uplink Shared Channel)
・ PRACH (Physical Random Access Channel)
The PUCCH is used for transmitting uplink control information (UPCI). The uplink control information includes downlink 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 (positive scheduling request) or a negative scheduling request (negative scheduling request). A positive scheduling request indicates requesting UL-SCH resources for initial transmission. A negative scheduling request indicates that no UL-SCH resource is required for initial transmission.

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

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

In this 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 apparatus 3 may be common signaling for a plurality of terminal apparatuses 1 in the cell. Further, the RRC signaling transmitted from the base station device 3 may be signaling dedicated to a certain terminal device 1 (also referred to as dedicated signaling). That is, user apparatus specific (user apparatus specific) information is transmitted to a certain terminal apparatus 1 using dedicated signaling.

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

In uplink wireless communication, the following uplink physical signals are used. The uplink physical signal is not used for transmitting 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 apparatus 3 to the terminal apparatus 1, the following downlink physical channels are used. The downlink physical channel is used for transmitting information output from an 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 (Master Information Block: MIB, Broadcast Channel: BCH) commonly used in the terminal device 1.

PCFICH is used for transmitting information indicating a region (OFDM symbol) used for transmission of PDCCH.

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

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

The downlink assignment is used for scheduling a single PDSCH within a single cell. The downlink assignment is used for PDSCH scheduling 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 within 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 includes information indicating the number of the HARQ process in the downlink (downlink HARQ process Identifier / Identity, downlink HARQ process number). The HARQ information transmitted on the PDCCH together with the uplink grant related to 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 related to synchronous HARQ may not include information (uplink HARQ process Identifier / Identity uplink HARQ process number) indicating the number of the HARQ process in the uplink.

NDI instructs initial transmission or re-transmission. A HARQ entity triggers an initial transmission to a HARQ process if the NDI provided by the HARQ information is toggled against the value of the NDI for a previous transmission of the HARQ process. Instruct them to do so. The HARQ entity triggers a retransmission to the HARQ process if the NDI provided by the HARQ information is not toggled compared to the value of the NDI for a previous transmission of the HARQ process. Instruct them to do so. Note that the HARQ process may determine whether the NDI is toggled.

The HARQ entity identifies the HARQ process corresponding to the uplink grant and HARQ information, and passes the uplink grant and HARQ information to the identified HARQ process. The HARQ process stores the uplink grant and HARQ information passed from the HARQ entity.

CRC (Cyclic Redundancy Check) parity bits added to downlink control information transmitted on one PDCCH are C-RNTI (Cell-Radio Network Temporary Identifier), SPS Semi-Persistent Scheduling (C-RNTI), or Temporary. 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 that 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 to transmit downlink data (Downlink Shared Channel: DL-SCH).

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

In downlink wireless communication, the following downlink physical signals are used. The downlink physical signal is not used for transmitting 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 for the terminal device 1 to synchronize the downlink frequency domain and time domain. In the TDD scheme, the synchronization signal is arranged in subframes 0, 1, 5, and 6 in the radio frame. In the FDD scheme, the synchronization signal is arranged in subframes 0 and 5 in the radio frame.

The downlink reference signal is used for the terminal device 1 to correct the propagation path of the downlink physical channel. The downlink reference signal is used for 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 collectively referred to as 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 referred to as a transport channel. A transport channel unit used in the MAC layer is also referred to as a transport block (transport block: TB) or a MAC PDU (Protocol Data Unit). In the MAC layer, HARQ (HybridbrAutomatic Repeat reQuest) is controlled for each transport block. The transport block is a unit of data that the MAC layer delivers to the physical layer. In the physical layer, the transport block is mapped to a code word, and an encoding process is performed for each code word.

The structure of the radio frame according to the present 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 a radio frame according to this embodiment. In FIG. 3, the horizontal axis is a time axis. Each of the type 1 and type 2 radio frames is 10 ms long 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 a (2 × i) th slot and a (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 downlink transmission and uplink transmission are not performed. Note that the special subframe may be composed of only DwPTS and GP, or may be composed of only GP and UpPTS.

The frame structure type 2 radio frame is composed of at least a downlink subframe, an uplink subframe, and a special subframe. The configuration of a radio frame of frame structure type 2 is indicated by UL-DL configuration (uplink-downlink configuration). The terminal device 1 receives 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 PDCCH according to a certain DCI format. PDCCH is transmitted in PDCCH candidates. The terminal device 1 monitors a set of PDCCH candidates (candidate) in the serving cell. A set of PDCCH candidates is referred to as 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 derived from at least the C-RNTI value set by the terminal device 1. That is, the UE-specific search space is derived individually for each terminal device 1. The common search space is a search space common to a plurality of terminal devices 1 and is configured by CCE (Control Channel Element) having a predetermined index. The CCE is composed of a plurality of resource elements.

The DCI format type will be described below.

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 scheduling of PUSCH in one cell. The uplink grant included in DCI format 0 and DCI format 0C is also referred to as the uplink grant included in 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 PUSCHEnh-Configuration for the serving cell is not set may decode the PDCCH including the DCI format 0 in the CSS and the USS. The terminal device 1 in which the PURCEnh-Configuration parameter of the RRC layer for the serving cell is set may decode the PDCCH including the DCI format 0 in the CSS in the serving cell, and include the DCI format 0C in the USS in the serving cell. May be decoded. The terminal device 1 in which the RRC layer parameter PUSCHEnh-Configuration for the serving cell is set does not have to decode the PDCCH including the DCI format 0 in the USS in the serving cell.

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

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

DCI format 0C includes a “Repetition number” field and a “HARQ process number” field. The terminal apparatus 1 in which the RRC layer parameter PUSCHEnh-Configuration for the serving cell is set performs PUSCH transmission in a set of subframes based on detection of PDCCH including 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 according to 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 referred to as a random access response grant. The random access response grant is used for PUSCH scheduling. The uplink grant included in the random access response corresponding to the contention-based random access procedure (contention-based random access procedure) does not include the "Repetition number" field and 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. An uplink included in a random access response corresponding to a non-contention-based random access procedure (non-contention-based random access procedure) and included in the random access response for the terminal device 1 in which the RRC layer parameter PUSCHEnh-Configuration is not set The grant does not include a “Repetition number” field. Random access response corresponding to a non-contention-based random access procedure (non-contention-based random access procedure), and included in the random access response for the terminal device 1 for which the parameter PUSCHEnh-Configuration of the RRC layer is set The grant includes a “Repetition number” field.

The random access procedure is 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, a plurality of random access procedures are not executed simultaneously.

In this embodiment, a contention-based random access procedure (contention-based random access procedure) and a non-contention-based random access procedure (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 information (RRC message) related to the random access procedure in the primary cell from the base station device 3. The information regarding the random access procedure in the primary cell includes information indicating a 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 a non-contention based random access procedure, an index of a random access preamble is selected based on information received from the base station device 3 by the terminal device 1. Here, the information received from the base station device 3 by the terminal device 1 may be included in the PDCCH. When the values of the bits of the information received from the base station device 3 are all 0, the contention-based random access procedure is executed by the terminal device 1 and the index of the random access preamble is selected by the terminal device 1 itself.

The random access response for the primary cell is transmitted on the 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 terminal 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 received random access response includes a random access preamble identifier corresponding to the transmitted random access preamble, and the terminal device 1 itself selects the random access preamble, the random access response that received the Temporary C-RNTI It is set to the value of the included Temporary C-RNTI field, and the random access message 3 is transmitted on the 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 Temporary C-RNTI is not set, the PUSCH corresponding to the uplink grant included in the random access response and the scrambling of PUSCH retransmission of the same transport block are based on C-RNTI.

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

When Temporary C-RNTI is set, the PUSCH retransmission of the transport block transmitted on the PUSCH corresponding to the uplink grant included in the random access response is accompanied by a CRC parity bit scrambled by the Temporary C-RNTI. Scheduled DCI format 0. The DCI format 0 is transmitted on the PDCCH of a common search space (Common Search Space).

Hereinafter, synchronous HARQ in the uplink will be described.

In synchronous HARQ, the HARQ process to which the uplink grant corresponds is related to 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 performs 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. Derived 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 illustrating 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 the HARQ process from the subframe in which UL-SCH data is transmitted in the MAC layer or the DCI format 0 corresponding to the UL-SCH data in the MAC layer is detected. It is.

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

In synchronous HARQ, a HARQ indicator is transmitted in PHICH in response to uplink transmission. The correspondence between the subframe in which uplink transmission is performed and the subframe in which the corresponding PHICH is transmitted is determined in advance. For example, the HARQ indicator for the MAC layer data is transmitted by PHICH in a subframe four times after the subframe in which the MAC layer data is transmitted by PUSCH. In addition, for example, in the subframe four times after the subframe in which NACK is received by PHICH, the MAC layer data is retransmitted by PUSCH.

Hereinafter, asynchronous HARQ in the uplink will be described.

FIG. 6 is a diagram illustrating 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 asynchronous HARQ, if the uplink grant (DCI format 0C) is included in the PDCCH mapped to the UE-specific search space, the HARQ entity derives the HARQ process from the “HARQ process number” field. In asynchronous HARQ, if an uplink grant (DCI format 0) is included in the PDCCH mapped to the common search space, the HARQ entity may use a specific number of HARQ processes. In asynchronous HARQ, if an uplink grant is included in the random access response, the HARQ entity may use a specific number of HARQ processes. The specific number may be zero. The specific number may be a predetermined number.

In asynchronous HARQ, the HARQ indicator is not transmitted in PHICH in response to uplink transmission. That is, in asynchronous HARQ, retransmission of data in the MAC layer 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 that has received the uplink grant. For example, data in the MAC layer corresponding to the uplink grant may be transmitted on the PUSCH in a subframe four times after the subframe that has received the uplink grant.

That is, 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 and the PDCCH, and / or ( 3) The HARQ process to which the uplink grant corresponds may be specified based at least on whether or not the RRC layer parameter PUSCHEnh-Configuration is configured.

Hereinafter, decoding of PDCCH for HARQ retransmission will be described.

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

The PUSCH initial transmission for the transport block means that the transport block is initially transmitted using the PUSCH. PUSCH retransmission for the transport block means retransmitting the transport block using the PUSCH.

The terminal device 1 and the base station device 3 are: (1) the type of random access procedure to which the random access response grant including the uplink grant for the PUSCH initial transmission for the transport block corresponds, and (2) the uplink Type of search space to which PDCCH including grant is mapped, (3) Whether uplink grant is included in random access response and PDCCH, and / or (4) RRC layer parameter PUSCHEnh-Configuration is set Whether process A to process C is to be executed may be determined based at least on whether or not the process is performed.

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

That is, the base station apparatus 3 (1) the type of random access procedure to which the random access response grant including the uplink grant for the PUSCH initial transmission for the transport block corresponds, and (2) the PDCCH including the uplink grant The type of search space to which is mapped, (3) whether the uplink grant is included in the random access response and PDCCH, and / or (4) whether the RRC layer parameter PUSCHEnh-Configuration is set Based on at least, which type of search space may determine whether to transmit the PDCCH for the PUSCH retransmission of the transport block.

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

Condition B is that the RRC layer parameter PUSCHEnh-Configuration is not set for the terminal device 1. Condition C is that the PDCCH for PUSCH initial transmission for the transport block is decoded. Condition D and condition 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. Condition E is that the parameter PUSCHEnh-Configuration of the RRC layer is set for the terminal device 1. Condition F is that the PDCCH for PUSCH initial transmission for the transport block is decoded in the UE-specific search space. Condition H is that the PDCCH for PUSCH initial transmission for the transport block is decoded in the common search space.

Hereinafter, the configuration of the apparatus according to the present embodiment will be described.

FIG. 8 is a schematic block diagram showing the configuration of the terminal device 1 of the present embodiment. As illustrated, the terminal device 1 includes 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 operation or the like to the radio transmission / reception unit 10. The upper layer processing unit 14 includes a medium access control (Medium Access Control: MAC) layer, a packet data integration protocol (Packet Data Convergence Protocol: PDCP) layer, a radio link control (Radio Link Control: RLC) layer, 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 performs processing of the medium access control layer. The medium access control layer processing unit 15 performs HARQ control 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 the 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 apparatus 3. That is, the radio resource control layer processing unit 16 sets various setting information / parameters based on information indicating various setting information / parameters received from the base station apparatus 3.

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

The RF unit 12 converts the signal received via the antenna unit 11 into a baseband signal by orthogonal demodulation (down-conversion: down covert), 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 a portion corresponding to CP (Cyclic Prefix) from the converted digital signal, performs fast Fourier transform (FFT) on the signal from which CP has been removed, and generates a frequency domain signal. Extract.

The baseband unit 13 performs inverse fast Fourier transform (Inverse Fastier Transform: IFFT) to generate an SC-FDMA symbol, adds a CP to the generated SC-FDMA symbol, and converts a baseband digital signal into Generating and converting a baseband digital signal to an analog signal. The baseband unit 13 outputs the converted analog signal to the RF unit 12.

The RF unit 12 removes an extra frequency component from the analog signal input from the baseband unit 13 using a low-pass filter, up-converts the analog signal to a carrier frequency, and transmits the signal via the antenna unit 11. To do. The RF unit 12 amplifies 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 apparatus 3 of the present embodiment. As shown in the figure, the base station apparatus 3 includes a radio 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 (Medium Access Control: MAC) layer, a packet data integration protocol (Packet Data Convergence Protocol: PDCP) layer, a radio link control (Radio Link Control: RLC) layer, 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 performs HARQ control 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). ACK / NACK and HARQ information for uplink data (UL-SCH) are transmitted to the terminal device 1 by 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), system information, RRC message, MAC CE (Control Element), etc. arranged in the physical downlink shared channel, or acquires it from the upper node. , Output to the wireless transceiver 30. 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 an upper layer signal. That is, the radio resource control layer processing unit 36 transmits / notifies information indicating various setting information / parameters.

Since the function of the wireless transmission / reception unit 30 is the same as that of the wireless transmission / reception unit 10, 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 transmission unit 10 that performs initial transmission of a transport block, and a random that includes an uplink grant for the initial transmission of the transport block. A receiving unit that selects a search space based on a type of a random access procedure corresponding to an access response and attempts to decode a 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 an initial transmission of a transport block, and an uplink grant for the initial transmission of the transport block. A transmission unit 30 that selects a search space based on a random access procedure type to which a 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 the PUSCH, and the retransmission is performed via the PUSCH.

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

(5) In the first and second aspects of the present embodiment, the type of the random access procedure includes a contention based random access procedure and a non-contention based random access procedure.

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

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

(8) In the first and second aspects of the present embodiment, the RRC layer parameter PUSCHEnh-Configuration corresponds to one serving cell, and the RRC layer parameter PUSCHEnh-Configuration is set for the terminal device. If the HARC 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. Is done.

(9) In the first aspect of the present embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal apparatus, 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 receiving unit 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 attempt to decode the PDCCH in the common search space.

(10) In the first aspect of this embodiment, an RRC layer parameter PUSCHEnh-Configuration is set for the terminal apparatus, 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 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 attempt 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 apparatus, and the uplink grant for the initial transmission of the transport block When the random access response including the message corresponds to the non-contention based random access procedure, the receiving unit 10 performs the retransmission of the transport block in the UE-specific search space and the common search space. Try to decode the PDCCH.

(12) In the first aspect of this embodiment, the RRC layer parameter PUSCHEnh-Configuration is not set for the terminal apparatus, and the uplink grant for the initial transmission of the transport block When the random access response including the message 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 attempt 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 apparatus, and the uplink grant for the initial transmission of the transport block is When the included random access response corresponds to the non-contention based random access procedure, the transmission unit 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 apparatus, and the uplink grant for the initial transmission of the transport block is When the included random access response corresponds to the contention-based random access procedure, the transmission unit transmits the PDCCH for the retransmission of the transport block in the common search space.

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

(16) In the second aspect of this embodiment, the RRC layer parameter PUSCHEnh-Configuration is not set for the terminal apparatus, and the uplink grant for the initial transmission of the transport block When the random access response including the message corresponds to the contention-based random access procedure, the transmission 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, and 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 to which the uplink grant corresponds is determined based at least on a 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 having a predetermined number.

(19) A fourth aspect of the present embodiment is a base station apparatus, and 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 to which the uplink grant corresponds is determined based at least on a search space in which the PDCCH is transmitted.

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

Thereby, the terminal apparatus 1 can communicate with the base station apparatus 3 efficiently.

The base station apparatus 3 related to one aspect of the present invention and the program operating in the terminal apparatus 1 control a CPU (Central Processing Unit) and the like so as to realize the functions of the above-described embodiments related to one aspect of the present invention. It may be a program (a program that causes a computer to function). 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) and HDD (Hard Disk Drive). Reading, correction, and writing are performed by the CPU as necessary.

In addition, you may make it implement | achieve the terminal device 1 in the embodiment mentioned above, and a part of base station apparatus 3 with a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed.

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

Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short 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, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

Also, the base station device 3 in the above-described embodiment can be realized as an aggregate (device group) composed of a plurality of devices. Each of the devices constituting the device group may include a part or all of each function or each functional block of the base station device 3 according to the above-described embodiment. The device group only needs to have one function or each function block of the base station device 3. The terminal device 1 according to the above-described embodiment can also communicate with the base station device as an aggregate.

Further, the base station apparatus 3 in the above-described embodiment may be EUTRAN (Evolved Universal Terrestrial Radio Access Network). In addition, the base station device 3 in the above-described embodiment may have a part or all of the functions of the upper node for the eNodeB.

In addition, a part or all of the terminal device 1 and the base station device 3 in the above-described embodiment may be realized as an LSI that 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 chipped, or a part or all of them may be integrated 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 an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

In the above-described embodiment, the terminal device is described as an example of the communication device. However, the present invention is not limited to this, and the stationary or non-movable electronic device installed indoors or outdoors, For example, the present invention can also be applied to terminal devices or communication devices such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other daily life equipment.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. In addition, one aspect of the present invention can be modified in various ways within the scope of the claims, and the technical aspects of the present invention also relate to embodiments obtained by appropriately combining technical means disclosed in different embodiments. Included in the range. Moreover, it is the element described in each said embodiment, and the structure which substituted the element which has the same effect is also contained.

One embodiment of the present invention is used in, for example, a communication system, a communication device (for example, a mobile phone device, a base station device, a wireless LAN device, or a sensor device), an integrated circuit (for example, a communication chip), a program, or the like. be able to.

1 (1A, 1B, 1C) Terminal device 3 Base station device 10 Wireless transmission / reception 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 Wireless 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)

1. A transmitter that performs initial transmission of the transport block;
   A search space is selected based on a type of random access procedure to which a random access response including an uplink grant for the initial transmission of the transport block corresponds, and retransmission of the transport block in the selected search space A receiving unit that attempts to decode PDCCH for the terminal device.
2. A receiver for receiving an initial transmission of a transport block;
   A search space is selected based on a type of random access procedure to which a random access response including an uplink grant for the initial transmission of the transport block corresponds, and retransmission of the transport block in the selected search space A transmission unit that transmits a PDCCH for the base station apparatus.
3. A communication method used for a terminal device,
   Perform the initial transmission of the transport block,
   A search space is selected based on a type of random access procedure to which a random access response including an uplink grant for the initial transmission of the transport block corresponds, and retransmission of the transport block in the selected search space A communication method that attempts to decode PDCCH for a PC.
4. A communication method used in a base station device,
   Receive the initial transmission of the transport block,
   A search space is selected based on a type of random access procedure to which a random access response including an uplink grant for the initial transmission of the transport block corresponds, and retransmission of the transport block in the selected search space Communication method for transmitting PDCCH for
5. A receiver for decoding the PDCCH including the uplink grant;
   A medium access control layer processing unit for managing a plurality of HARQ processes,
   The HARQ process to which the uplink grant corresponds is determined based on at least a search space in which the PDCCH is decoded.
6. The terminal apparatus 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.
7. A transmitter that transmits a PDCCH including an uplink grant;
   A medium access control layer processing unit for managing a plurality of HARQ processes,
   The HARQ process to which the uplink grant corresponds is determined based on at least a search space in which the PDCCH is transmitted.
8. 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.

Images