JP2021016188A - Base station, communication method, and integrated circuit - Google Patents

Abstract

To avoid PUCCH resource collision between a normal mode terminal and an MTC coverage enhancement mode terminal.SOLUTION: A receiving section 202 receives control information indicating assignment of downlink data, and the downlink data; and a transmitting section transmits a response signal using a resource in a first resource group when an own terminal is a first terminal to which repetition transmission is applied, and the transmitting section transmits the response signal using a resource in a second resource group that is different from the first resource group, when the own terminal is a second terminal to which the repetition transmission is not applied.SELECTED DRAWING: Figure 9

Description

The present disclosure relates to base stations, communication methods and integrated circuits.

In 3GPP LTE (3rd Generation Partnership Project Long Term Evolution), Orthogonal Frequency Division Multiple Access (OFDMA) is adopted as a downlink communication method.

In wireless communication systems to which 3GPP LTE is applied, base stations (sometimes called eNBs) use predetermined communication resources to synchronize signals (SCH: Synchronization Channel) and broadcast signals (PBCH: Physical Broadcast Channel). ) Is sent. Then, the terminal (sometimes called UE (User Equipment)) first secures synchronization with the base station by catching the SCH. After that, the terminal acquires the parameters unique to the base station (for example, frequency bandwidth) by reading the BCH information (see, for example, Non-Patent Documents 1 to 3).

In addition, the terminal establishes communication with the base station by making a connection request to the base station after the acquisition of the parameters unique to the base station is completed. The base station transmits control information to a terminal for which communication has been established, if necessary, via a control channel such as PDCCH (Physical Downlink Control Channel). Then, the terminal makes a "blind determination" for each of the plurality of control information included in the received PDCCH signal. That is, the control information includes a CRC (Cyclic Redundancy Check) portion, and this CRC portion is masked by the terminal ID of the transmission target terminal in the base station. Therefore, the terminal cannot determine whether or not the control information is addressed to the own device until the CRC portion of the received control information is demasked by the terminal ID of the own device. In this blind determination, if the CRC calculation is OK as a result of demasking, it is determined that the control information is addressed to the own machine.

In LTE, HARQ (Hybrid Automatic Repeat Request) is applied to the downlink data from the base station to the terminal. That is, the terminal feeds back the response signal indicating the error detection result of the downlink data to the base station. The terminal performs CRC on the downlink data, and if CRC = OK (no error), an acknowledgment (ACK: Acknowledgement) is performed, and if CRC = NG (with an error), a negative response (NACK: Negative Acknowledgement) is performed. ) Is fed back to the base station as a response signal. An uplink control channel such as PUCCH (Physical Uplink Control Channel) is used for feedback of this response signal (that is, ACK / NACK signal).

Here, the control information transmitted from the base station includes resource allocation information including resource information allocated to the terminal by the base station. As described above, PDCCH is used to transmit this control information. The PDCCH is composed of one or more L1 / L2 CCHs (L1 / L2 Control Channels). Each L1 / L2 CCH is composed of one or more CCEs (Control Channel Elements). That is, CCE is a basic unit when mapping control information to PDCCH. When one L1 / L2 CCH is composed of a plurality of CCEs, a plurality of consecutive CCEs are assigned to the L1 / L2 CCH. The base station allocates L1 / L2 CCH to the resource allocation target terminal according to the number of CCEs required for notification of control information to the resource allocation target terminal. Then, the base station maps the control information to the physical resource corresponding to the CCE of this L1 / L2 CCH and transmits it.

Further, each CCE is associated with a PUCCH configuration resource (hereinafter referred to as a PUCCH resource) on a one-to-one basis. Therefore, the terminal receiving the L1 / L2 CCH identifies the PUCCH resource corresponding to the CCE constituting the L1 / L2 CCH, and transmits the ACK / NACK signal to the base station using this PUCCH resource. However, when the L1 / L2 CCH occupies a plurality of consecutive CCEs, the terminal is one of the plurality of PUCCH resources corresponding to the plurality of CCEs (for example, the PUCCH corresponding to the CCE having the smallest index). The resource) is used to transmit the ACK / NACK signal to the base station.

Further, as shown in FIG. 1, the transmission timing of the ACK / NACK signal on the PUCCH in the terminal is the subframe in which the PDSCH (Physical Downlink Shared Channel) signal to which the data is assigned by the received PDCCH signal and the PDDCH signal is received. (Subframe n in FIG. 1) becomes a subframe (subframe n + K in FIG. 1) after K subframe (for example, K = 4 in FDD (Frequency Division Duplex)).

As shown in FIG. 2, the plurality of ACK / NACK signals transmitted from the plurality of terminals are ZAC (Zero Auto-correlation) series, Walsh series, and DFT (DFT) having Zero Auto-correlation characteristics on the time axis. Discrete Fourier Transform) Spread by sequence and code-multiplexed within PUCCH. In FIG. 2, (W (0), W (1), W (2), W (3)) represents a Walsh series with a series length of 4, and (F (0), F (1), F (2)). ) Represents a DFT series with a series length of 3.

As shown in FIG. 2, in the terminal, the ACK / NACK signal is first diffused on the frequency axis by the ZAC sequence (series length 12) to the frequency component corresponding to the 1SC-FDMA (Single-Carrier Frequency Division Multiple Access) symbol. Will be done. That is, the ACK / NACK signal component represented by a complex number is multiplied by the ZAC series having a series length of 12. Next, the ACK / NACK signal after the primary diffusion and the ZAC series as the reference signal are the Walsh series (series length 4: W (0) to W (3)) and the DFT series (series length 3: F, respectively). It is secondarily diffused by (0) to F (2)). That is, for each component of a signal having a sequence length of 12 (ACK / NACK signal after primary diffusion or ZAC sequence as a reference signal), each of the orthogonal code sequences (Orthogonal sequence: Walsh sequence or DFT sequence). The components are multiplied. Further, the second-order diffused signal is transformed into a signal having a sequence length of 12 on the time axis by an inverse discrete Fourier transform (IDFT) or IFFT: Inverse Fast Fourier Transform. Then, a cyclic prefix (CP: Cyclic Prefix) is added to each of the signals after IFFT, and a one-slot signal consisting of seven SC-FDMA symbols is formed.

PUCCHs are located at both ends of the system band on the frequency axis. In PUCCH, wireless resources are allocated to each terminal in subframe units. Further, one subframe is composed of two slots, and PUCCH is frequency hopping (inter-slot frequency hopping) in the first half slot and the second half slot.

ACK / NACK signals from different terminals are spread using a ZAC sequence corresponding to a different cyclic shift index (Cyclic Shift Index) or an orthogonal code sequence corresponding to a different sequence number (OC Index: Orthogonal Cover Index). ing. The Walsh-Hadamard sequence is a pair of Walsh sequence and DFT sequence. The Walsh-Hadamard sequence may also be referred to as a Block-wise spreading code. Therefore, the base station can separate these code-multiplexed plurality of ACK / NACK signals by using conventional despreading and correlation processing (see, for example, Non-Patent Document 4). FIG. 3 shows PUCCH resources defined by the series number (OC index: 0 to 2) of the orthogonal code series and the cyclic shift amount (Cyclic shift Index: 0 to 11) of the ZAC series. When using the Walsh sequence with a sequence length of 4 and the DFT sequence with a sequence length of 3, there are a maximum of 3 * 12 = 36 PUCCH resources in the same subcarrier. However, not all 36 PUCCH resources are available. For example, FIG. 3 shows a case where 18 PUCCH resources (# 0 to # 17) are made available.

By the way, as a mechanism to support the information society in the future, M2M (Machine-to-Machine) communication, which realizes a service by autonomous communication between devices without the judgment of a user, is expected in recent years. There is a smart grid as a concrete application example of the M2M system. A smart grid is an infrastructure system that efficiently supplies lifelines such as electricity or gas, and autonomously and effectively implements M2M communication between smart meters installed in each home or building and a central server. Adjust the demand balance of resources. Other application examples of M2M communication systems include monitoring systems for goods management or telemedicine, remote management of vending machine inventory or billing, and the like.

In the M2M communication system, attention is paid to the use of a cellular system having a particularly wide communication area. In 3GPP, the study of M2M based on the cellular network in the standardization of LTE and LTE-Advanced is underway under the name of Machine Type Communication (MTC). In particular, in order to deal with cases where MTC communication equipment such as smart meters in the basement of a building is placed in a place that cannot be used in the existing communication area, "Coverage Enhancement" to further expand the communication area is being considered. (See, for example, Non-Patent Document 5).

In particular, in MTC coverage enhancement, repetition in which the same signal is repeatedly transmitted multiple times is considered to be an important technology for expanding the communication area. Specifically, it is assumed that repetition transmission is performed on each channel such as PDCCH, PDSCH, and PUCCH.

3GPP TS 36.211 V11.5.0, “Physical channels and modulation (Release 11),” December 2013. 3GPP TS 36.212 V11.4.0, “Multiplexing and channel coding (Release 11),” December 2013. 3GPP TS 36.213 V11.5.0, “Physical layer procedures (Release 11),” December 2013. Seigo Nakao, Tomofumi Takata, Daichi Imamura, and Katsuhiko Hiramatsu, “Performance enhancement of E-UTRA uplink control channel in fast fading environments,” Proceeding of 2009 IEEE 69th Vehicular Technology Conference (VTC2009-Spring), April 2009. 3GPP TR 36.888 V12.0.0, “Study on provision of low-cost Machine-Type Communications (MTC) User Equipments (UEs) based on LTE,” June 2013.

However, the PUCCH resource for which the terminal in the MTC coverage enhancement mode (the terminal that performs repetition transmission) transmits the ACK / NACK signal has not yet been sufficiently examined. In particular, when a terminal in MTC coverage enhancement mode and a terminal in normal mode (terminals that do not perform repetition transmission) coexist, the terminal in normal mode can use the PUCCH resources used by the terminal in MTC coverage enhancement mode. It should be designed so that it does not conflict with the PUCCH resources used.

One aspect of the present disclosure is to avoid collision of PUCCH resources between a terminal in normal mode and a terminal in MTC coverage enhancement mode without reducing the frequency utilization efficiency of PDCCH resources and increasing the complexity of scheduling. It is to provide terminals, communication methods and integrated circuits that can be used.

The base station according to one aspect of the present disclosure is specified from the correspondence between the downlink control information and the transmission unit that transmits downlink data to the terminal and the uplink control channel resource determined based on the control information. , A receiver that receives a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts. In the correspondence, a coverage enhancement mode capable of repeating transmission over a plurality of subframes of the response signal is set in the terminal based on the difference in the amount of adjacent cyclic shifts combined in one orthogonal code sequence. The difference in the amount of the cyclic shift when the mode is set is set independently of the difference in the amount of the cyclic shift when the coverage enhancement mode is not set in the terminal.

The base station according to one aspect of the present disclosure is specified from the correspondence between the downlink control information and the transmission unit that transmits downlink data to the terminal and the uplink control channel resource determined based on the control information. , A receiver that receives a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts. In the association, the terminal provides the downlink control information capable of repeating transmission over a plurality of subframes in which the coverage enhancement mode is set, based on the difference in the amount of adjacent cyclic shifts combined in one orthogonal code sequence. The difference in the amount of the cyclic shift when the data is transmitted to is set independently of the difference in the amount of the cyclic shift when the coverage enhancement mode is not set.

In the communication method according to one aspect of the present disclosure, the base station associates a transmission step of transmitting downlink control information and downlink data to a terminal with an uplink control channel resource determined based on the control information. A receiving step of receiving a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts specified from the above. The association comprises a coverage enhancement mode capable of repeating transmission of the response signal over a plurality of subframes based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence. The difference in the cyclic shift amount when the terminal is set is set independently of the difference in the cyclic shift amount when the coverage enhancement mode is not set in the terminal.

In the communication method according to one aspect of the present disclosure, the base station associates a transmission step of transmitting downlink control information and downlink data to a terminal with an uplink control channel resource determined based on the control information. A receiving step of receiving a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts specified from the above. The downlink control capable of transmitting repetition over a plurality of subframes in which the coverage enhancement mode is set, based on the difference in the amount of adjacent cyclic shifts combined in one orthogonal code sequence. The difference in the cyclic shift amount when the information is transmitted to the terminal is set independently of the difference in the cyclic shift amount when the coverage enhancement mode is not set.

The integrated circuit according to one aspect of the present disclosure is specified from the correspondence between the downlink control information and the transmission process of transmitting the downlink data to the terminal and the uplink control channel resource determined based on the control information. Controls reception processing for receiving a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts. In the correspondence, a coverage enhancement mode capable of repeating transmission over a plurality of subframes of the response signal is set in the terminal based on the difference in the amount of adjacent cyclic shifts combined in one orthogonal code sequence. The difference in the amount of the cyclic shift when the mode is set is set independently of the difference in the amount of the cyclic shift when the coverage enhancement mode is not set in the terminal.

The integrated circuit according to one aspect of the present disclosure is specified from the correspondence between the downlink control information and the transmission process of transmitting the downlink data to the terminal and the uplink control channel resource determined based on the control information. Controls reception processing for receiving a response signal to the downlink data transmitted from the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts. In the association, the terminal provides the downlink control information capable of repeating transmission over a plurality of subframes in which the coverage enhancement mode is set, based on the difference in the amount of adjacent cyclic shifts combined in one orthogonal code sequence. The difference in the amount of the cyclic shift when the data is transmitted to is set independently of the difference in the amount of the cyclic shift when the coverage enhancement mode is not set.

According to one aspect of the present disclosure, PUCCH resource collisions between terminals in normal mode and terminals in MTC coverage enhancement mode are avoided without reducing the frequency utilization efficiency of PDCCH resources and increasing the complexity of scheduling. can do.

Diagram showing transmission timing of each channel The figure which shows the diffusion method of a response signal and a reference signal Diagram showing an example of PUCCH resource The figure which shows the transmission timing of each channel at the time of repetition transmission Diagram showing an example of PUCCH resource collision Block diagram showing the main part configuration of the base station according to the first embodiment Block diagram showing the main part configuration of the terminal according to the first embodiment Block diagram showing the configuration of the base station according to the first embodiment Block diagram showing the configuration of the terminal according to the first embodiment The figure which shows the PUCCH resource which concerns on Embodiment 1. The figure which shows the PUCCH resource which concerns on Embodiment 2. The figure which shows the PUCCH resource which concerns on Embodiment 3. The figure which shows the correspondence between CCE and PUCCH resource which concerns on Embodiment 4. The figure which shows the correspondence between CCE and PUCCH resource which concerns on Embodiment 4. The figure which shows an example of the collision of PUCCH resource which concerns on Embodiment 5. The figure which shows the transmission timing of each channel which concerns on Embodiment 5. The figure which shows an example of the collision of PUCCH resource which concerns on Embodiment 6. The figure which shows the transmission timing of each channel which concerns on Embodiment 6.

FIG. 4 shows the transmission timing of each channel in the MTC coverage enhancement assumed as one aspect of the present disclosure. In FIG. 4, the repetition level of PDCCH (number of repetitions or repetition factor) is N _PDCCH , the repetition level of _PDSCH is N _PDSCH, and the repetition level of _PUCCH is N _PUCCH . Further, as shown in FIG. 4, in MTC coverage enhancement, after the repetition transmission of the PDCCH, the repetition transmission of the PDSCH to which the data is assigned by the PDCCH is performed. The transmission timing of the ACK / NACK signal (PUCCH) at the terminal is from the subframe after receiving the PDSCH to the K _MTC subframe.

For downlink control signals when a terminal in MTC coverage enhancement mode (terminal that performs repetition transmission) and a terminal in normal mode (terminal that does not perform repetition transmission) coexist in an area covered by the same base station. If the control channels are provided separately, the frequency utilization efficiency will decrease. Therefore, it is conceivable to set the downlink control channel (PDCCH) using the same frequency for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

At this time, between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode, the subframe in which the ACK / NACK signal is transmitted (the first subframe in which the PUCCH repetition transmission is performed) and the ACK / NACK signal are transmitted. The time interval between the PUCCH resource used and the subframe in which the PDCCH containing the associated CCE is transmitted (the last subframe in which the PDCCH repetition transmission is performed) is different. Therefore, when both terminals transmit the ACK / NACK signal in the same subframe, the CCE number associated with the PUCCH resource to which the normal mode terminal transmits the ACK / NACK signal and the MTC coverage enhancement mode terminal ACK. The CCE number associated with the PUCCH resource that sends the / NACK signal may overlap. In this case, the ACK / NACK signal is transmitted using the same PUCCH resource on both terminals.

FIG. 5 shows an example of a case where the PUCCH resource of the terminal in the normal mode and the PUCCH resource of the terminal in the MTC coverage enhancement mode collide with each other. In FIG. 5, let n be a subframe in which a collision of PUCCH resources occurs.

In this case, the PDCCH is transmitted in the subframe nK and the PDSCH assigned by the PDCCH is transmitted in the same subframe nK to the terminal in the normal mode. On the other hand, for terminals in MTC coverage enhancement mode, PDCCH is transmitted in subframes nK _MTC -N _PDSCH -N _{PDCCH to} nK _MTC -N _PDSCH -1. The PDSCH assigned by the PDCCH is transmitted in the subframes nK _MTC -N _{PDSCH to} nK _MTC -1.

If the subframe in which the terminal in normal mode transmits PDCCH and the subframe in which the terminal in MTC coverage enhancement mode transmits PDCCH overlap, both terminals should not transmit PDCCH using the same CCE. Scheduled to. However, in other cases (for example, in the case of FIG. 5), the same CCE can be used for PDCCH transmission to the terminal in the normal mode and PDCCH repetition transmission to the terminal in the MTC coverage enhancement mode. For example, in FIG. 5, CCE # 0 to CCE # 3 are used for PDCCH for a terminal in MTC coverage enhancement mode, and the terminal corresponds to CCE # 0 (the smallest index among CCE # 0 to CCE # 3). Use the PUCCH resource. Further, in FIG. 5, CCE # 0 and CCE # 1 are used for PDCCH for the terminal in the normal mode, and the terminal is a PUCCH resource corresponding to CCE # 0 (smaller index among CCE # 0 and CCE # 1). Is used.

As a result, a collision of PUCCH resources that transmit an ACK / NACK signal occurs between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

To prevent the PUCCH resource that the normal mode terminal sends the ACK / NACK signal and the PUCCH resource that the MTC coverage enhancement mode terminal sends the ACK / NACK signal collide with, the PDCCH allocation of the normal mode terminal is assigned on the base station side. It is also possible to control (do not assign the CCE used for the terminal in MTC coverage enhancement mode in the past subframe to the terminal in normal mode). However, in this case, there are problems such as a decrease in utilization efficiency of PDCCH resources or an increase in scheduling complexity.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[Outline of communication system]
In the following description, an FDD (Frequency Division Duplex) system will be described as an example.

Further, the communication system according to each embodiment of the present disclosure is, for example, a system corresponding to LTE-Advanced, and includes a base station 100 and a terminal 200.

A normal mode or an MTC coverage enhancement mode is set in the terminal 200. For example, when the MTC coverage enhancement mode is applied, the terminal 200 applies repetition transmission over a plurality of subframes when transmitting PDCCH, PDSCH, or PUCCH. That is, the terminal 200 repeatedly transmits the same signal in continuous subframes for a predetermined repetition level.

FIG. 6 is a block diagram showing a configuration of a main part of the base station 100 according to the embodiment of the present disclosure. In the base station 100 shown in FIG. 6, the transmission unit 112 transmits control information (PDCCH signal) indicating the allocation of downlink data and downlink data (PDSCH signal), and the control unit 101 sends the control information to the control information. Based on this, the resource used for the ACK / NACK signal for the downlink data is determined, and the ACK / NACK signal receiving unit (PUCCH extraction unit 116, despreading unit 118, correlation processing unit 119) determines the determined resource. Receives ACK / NACK signals using. Here, the receiving unit sets the ACK / NACK signal transmitted from the first terminal to which the repetition transmission is applied to the control information, the downlink data, and the ACK / NACK signal to the first resource group (1st resource group ( The ACK / NACK signal received from the resources in the PUCCH resource area) and transmitted from the second terminal to which the repetition transmission is not applied is a second resource group (PUCCH resource) different from the first resource group. Receive using the resources in the area).

Further, FIG. 7 is a block diagram showing a main configuration of the terminal 200 according to each embodiment of the present disclosure. In the terminal 200 shown in FIG. 7, the receiving unit 202 receives the control information indicating the allocation of the downlink data and the downlink data, and the control unit 213 receives ACK / for the downlink data based on the control information. The resource used for the NACK signal is determined, and the ACK / NACK signal transmission unit (primary diffusion unit 216, secondary diffusion unit 217, IFFT unit 218) transmits the ACK / NACK signal using the determined resource. To do. Here, the transmission unit is included in the first resource group when the own terminal is the first terminal to which repetition transmission is applied to the control information, downlink data, and ACK / NACK signal. The ACK / NACK signal is transmitted using the resource, and if the local terminal is the second terminal to which the repetition transmission is not applied, the resource in the second resource group different from the first resource group is used. And sends an ACK / NACK signal.

(Embodiment 1)
[Base station configuration]
FIG. 8 is a block diagram showing the configuration of the base station 100 according to the first embodiment of the present disclosure. In FIG. 8, the base station 100 includes a control unit 101, a control signal generation unit 102, a control signal coding unit 103, a control signal modulation unit 104, a broadcast signal generation unit 105, and a data coding unit 106. Retransmission control unit 107, data modulation unit 108, signal allocation unit 109, IFFT unit 110, CP addition unit 111, transmission unit 112, antenna 113, reception unit 114, CP removal unit 115, and PUCCH. It has an extraction unit 116, a sequence control unit 117, a reverse diffusion unit 118, a correlation processing unit 119, and a determination unit 120.

The control unit 101 transmits downlink resources (downlink control information allocation resources) for transmitting control information and downlink data (transmission data) included in the control information to the resource allocation target terminal 200. Allocate the downlink resource (downlink data allocation resource) for. The downlink control information allocation resource is selected in the resource corresponding to PDCCH or EPDCCH (Enhanced PDCCH). In addition, the downlink data allocation resource is selected in the resource corresponding to PDSCH. When there are a plurality of resource allocation target terminals 200 in the same subframe, the control unit 101 allocates different resources to each of the resource allocation target terminals 200. The downlink control information allocation resource is equivalent to the above-mentioned L1 / L2 CCH. That is, the downlink control information allocation resource is composed of one or more CCEs. Further, when the PUCCH is notified to Implicit by using the CCE as described above, each CCE is associated with the PUCCH resource in the uplink control channel area (PUCCH area).

The control unit 101 identifies the PUCCH resource (frequency and the code used for the primary spread / secondary spread) corresponding to the CCE occupied by the PDCCH including the control information. The control unit 101 provides information on the ZAC sequence and the orthogonal code sequence (that is, the PUCCH resource) that may be used for spreading the PUCCH signal (ACK / NACK signal and reference signal) transmitted from the terminal 200. It outputs to 117, and outputs the information about the frequency to the PUCCH extraction unit 116.

Further, the control unit 101 determines the coding rate to be used when transmitting the control information to the resource allocation target terminal 200, and outputs the determined coding rate to the control signal coding unit 103. Further, the control unit 101 determines the coding rate to be used when transmitting the downlink data to the resource allocation target terminal 200, and outputs the determined coding rate to the data coding unit 106.

Since the amount of control information data differs depending on the determined coding rate, the control unit 101 allocates a downlink control information allocation resource including a CCE capable of mapping the control information of this amount of data. The control unit 101 outputs information regarding the downlink data allocation resource to the control signal generation unit 102. Further, the control unit 101 outputs information regarding the downlink data allocation resource and the downlink control information allocation resource to the signal allocation unit 109.

Further, when the MTC coverage enhancement mode is set for the resource allocation target terminal 200, the control unit 101 provides information on the repetition level (number of repetitions) for each channel (PDCCH, PDSCH or PUCCH) of the terminal 200. Is output to the control signal generation unit 102 and the data coding unit 106.

Further, the control unit 101 instructs the broadcast signal generation unit 105 to generate a broadcast signal based on a parameter determined in advance for each base station.

Further, the control unit 101 generates information about the PUCCH resource and outputs the information to the control signal generation unit 102. The information about the PUCCH resource is, for example, a parameter for identifying the PUCCH resource used in the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Information about the PUCCH resource may be notified to the terminal 200 as notification information as a cell-specific value, or may be notified to the terminal 200 as signaling of an upper layer.

The control signal generation unit 102 generates a control signal using the information received from the control unit 101 (information about the downlink data allocation resource, information about the repetition level of PUCCH or information about the PUCCH resource), and encodes the control signal into the control signal. Output to unit 103. When there are a plurality of resource allocation target terminals 200, the control signal includes the terminal ID of the destination terminal in order to distinguish between the resource allocation target terminals 200. For example, the control signal includes a CRC bit masked by the terminal ID of the destination terminal. Further, when the MTC coverage enhancement mode is set for the resource allocation target terminal 200, the control signal generation unit 102 generates a repetition signal according to the information regarding the repetition level received from the control unit 101. That is, when the repetition level of PDCCH is larger than 1, the control signal generation unit 102 sends the same control signal to the control signal coding unit 103 over a plurality of consecutive subframes corresponding to the repetition level. Output.

The control signal coding unit 103 encodes the control signal received from the control signal generation unit 102 according to the coding rate received from the control unit 101, and outputs the coded control signal to the control signal modulation unit 104.

The control signal modulation unit 104 modulates the control signal received from the control signal coding unit 103, and outputs the modulated control signal to the signal allocation unit 109.

The notification signal generation unit 105 generates a notification signal according to an instruction from the control unit 101, and outputs the notification signal to the signal allocation unit 109. The broadcast signal includes, for example, a system bandwidth, a signal related to the PUCCH resource, and the like. Further, the broadcast signal may be subjected to coding processing and modulation processing.

The data coding unit 106 encodes transmission data (bit series, that is, downlink data) for each destination terminal according to the coding rate received from the control unit 101, and outputs the encoded data signal to the retransmission control unit 107. To do. Further, when the MTC coverage enhancement mode is set for the resource allocation target terminal 200, the data coding unit 106 generates a repetition signal according to the information regarding the repetition level received from the control unit 101. That is, when the repetition level of PDSCH is greater than 1, the data coding unit 106 outputs the same data signal to the retransmission control unit 107 over a plurality of consecutive subframes corresponding to the repetition level. ..

At the time of initial transmission, the retransmission control unit 107 holds the coded data signal received from the data coding unit 106 and outputs it to the data modulation unit 108. The retransmission control unit 107 holds the encoded data signal for each destination terminal. Further, when the retransmission control unit 107 receives the NACK for the transmitted data signal from the determination unit 120 described later, the retransmission control unit 107 outputs the corresponding holding data to the data modulation unit 108. When the retransmission control unit 107 receives the ACK for the transmitted data signal, the retransmission control unit 107 deletes the corresponding retained data.

The data modulation unit 108 modulates the data signal received from the retransmission control unit 107, and outputs the data modulation signal to the signal allocation unit 109.

The signal allocation unit 109 receives the control signal received from the control signal modulation unit 104, the notification signal received from the notification signal generation unit 105, and the data modulation signal received from the data modulation unit 106 as downlink resources (downlink data signal allocation resource, downlink). It is mapped to the link control information allocation resource, etc.), and the mapped signal is output to the IFFT unit 110. Specifically, the signal allocation unit 109 maps the control signal to the resource indicated by the downlink control information allocation resource received from the control unit 101, and transmits the data modulation signal to the resource indicated by the downlink data allocation resource received from the control unit 101. Map. Further, the signal allocation unit 109 maps the broadcast signal to the preset time / frequency resources.

The IFFT unit 110 converts the frequency domain signal into a time domain signal by performing IFFT processing on the signal received from the signal allocation unit 109. The IFFT unit 110 outputs a time domain signal to the CP addition unit 111.

The CP addition unit 111 adds a CP to the signal received from the IFFT unit 110, and outputs the signal (OFDM signal) after the CP addition to the transmission unit 112.

The transmission unit 112 performs RF (Radio Frequency) processing such as D / A (Digital-to-Analog) conversion and up-conversion on the OFDM signal received from the CP addition unit 111, and wirelessly transmits to the terminal 200 via the antenna 113. Send a signal.

The receiving unit 114 performs RF processing such as down-conversion or A / D (Analog-to-Digital) conversion on the radio signal from the terminal 200 received via the antenna 113, and CPs the obtained received signal. Output to the removal unit 115.

The CP removing unit 115 removes the CP added to the received signal received from the receiving unit 114, and outputs the signal after removing the CP to the PUCCH extraction unit 116.

The PUCCH extraction unit 116 extracts an uplink control channel signal (PUCCH) from the signal received from the CP removal unit 115 based on the information received from the control unit 101, and outputs the extracted PUCCH to the reverse diffusion unit 118. Further, when the terminal 200 in the MTC coverage enhancement mode is present, the PUCCH extraction unit 116 extracts the PUCCH (synthesized signal) by performing homeomorphic synthesis on the PUCCH that has been repeatedly transmitted over a plurality of subframes.

The sequence control unit 117 has a ZAC sequence that may be used to spread the ACK / NACK signal and the reference signal transmitted from the terminal 200 based on the information about the ZAC sequence and the orthogonal code sequence received from the control unit 101, and the sequence control unit 117. Generate an orthogonal code sequence. The sequence control unit 117 outputs the orthogonal code sequence to the reverse diffusion unit 118 and outputs the ZAC sequence to the correlation processing unit 119.

The despreading unit 118 uses the walsh-Hadamard sequence received from the sequence control unit 117 (the walsh-Hadamard sequence that the terminal 200 should use in the secondary diffusion), and the portion corresponding to the ACK / NACK signal among the signals received from the PUCCH extraction unit 116. The signal of is despread, and the signal after despreading is output to the correlation processing unit 119.

The correlation processing unit 119 obtains a correlation value between the ZAC series (ZAC series that the terminal 200 may use in the primary diffusion) input from the series control unit 117 and the signal input from the despreading unit 118. , The correlation value is output to the determination unit 120.

The determination unit 120 determines whether the ACK / NACK signal transmitted from the terminal 200 indicates either ACK or NACK with respect to the transmitted data, based on the correlation value received from the correlation processing unit 119. The determination unit 120 outputs the determination result to the retransmission control unit 107.

[Terminal configuration]
FIG. 9 is a block diagram showing the configuration of the terminal 200 according to the first embodiment of the present disclosure. In FIG. 9, the terminal 200 includes an antenna 201, a receiving unit 202, a CP removing unit 203, an FFT (Fast Fourier Transform) unit 204, an extracting unit 205, a notification signal receiving unit 206, and a control signal demodulation unit 207. , Control signal decoding unit 208, determination unit 209, data demodulation unit 210, data decoding unit 211, CRC unit 212, control unit 213, ACK / NACK generation unit 214, modulation unit 215, 1 It has a secondary diffusion unit 216, a secondary diffusion unit 217, an IFFT unit 218, a CP addition unit 219, and a transmission unit 220.

The receiving unit 202 performs RF processing such as down-conversion or AD conversion on the radio signal from the base station 100 received via the antenna 201 to obtain a baseband OFDM signal. The receiving unit 202 outputs the OFDM signal to the CP removing unit 203.

The CP removing unit 203 removes the CP added to the OFDM signal received from the receiving unit 202, and outputs the signal after removing the CP to the FFT unit 204.

The FFT unit 204 converts the time domain signal into a frequency domain signal by performing FFT processing on the signal received from the CP removal unit 203. The FFT unit 204 outputs a frequency domain signal to the extraction unit 205.

The extraction unit 205 extracts the notification signal from the signal received from the FFT unit 204 and outputs it to the notification signal receiving unit 206. Here, since the resource to which the broadcast signal is mapped is predetermined, the extraction unit 205 obtains the broadcast signal by extracting the information mapped to the resource. The extracted broadcast signal includes, for example, a system bandwidth, a signal related to the PUCCH resource, and the like.

Further, the extraction unit 205 extracts a downlink control channel signal (PDCCH signal) from the signal received from the FFT unit 204 and outputs it to the control signal demodulation unit 207. Further, the extraction unit 205 extracts downlink data (PDSCH signal) from the signal received from the FFT unit 204 based on the information regarding the downlink data allocation resource addressed to the own terminal received from the determination unit 209, and sends it to the data demodulation unit 210. Output. The PDCCH signal includes, for example, information about the downlink data allocation resource, information about the repetition level of PUCCH, information about the PUCCH resource, and the like.

Further, when the MTC coverage enhancement mode is set for the own device and the PDCCH signal is repeated, the extraction unit 205 synthesizes in-phase with the PDCCH signal transmitted by repetition over a plurality of subframes. Then, the PDCCH signal is extracted. Similarly, when the downlink data (PDSCH signal) is repeated, the extraction unit 205 performs homeomorphic synthesis on the PDSCH signal that is repeated over a plurality of subframes, and performs downlink. Extract the data.

The broadcast signal receiving unit 206 obtains information about the system bandwidth, the PUCCH resource, and the like from the broadcast signal received from the extraction unit 205. When the broadcast signal is coded and modulated, the broadcast signal receiving unit 206 performs demodulation processing and decoding processing. The notification signal receiving unit 206 outputs the obtained notification signal to the determination unit 209 or the control unit 213.

The control signal demodulation unit 207 demodulates the PDCCH signal received from the extraction unit 205, and outputs the demodulated PDCCH signal to the control signal decoding unit 208.

The control signal decoding unit 208 decodes the PDCCH signal received from the control signal demodulation unit 207, and outputs the decoding result to the determination unit 209.

The determination unit 209 blindly determines whether or not the control information included in the decoding result received from the control signal decoding unit 208 is the control information addressed to the own terminal. For example, the determination unit 209 demasks the CRC bit according to the terminal ID of the own terminal, and determines that the control information for which CRC = OK (no error) is the control information addressed to the own terminal. Then, the determination unit 209 outputs the information regarding the downlink data allocation resource included in the control information addressed to the own device to the extraction unit 205. Further, the determination unit 209 identifies the CCE to which the control information addressed to the own device is mapped, and outputs the identification information of the specified CCE to the control unit 213.

The data demodulation unit 210 demodulates the downlink data received from the extraction unit 205, and outputs the demodulated downlink data to the data decoding unit 211.

The data decoding unit 211 decodes the downlink data received from the data demodulation unit 210, and outputs the decoded downlink data to the CRC unit 212.

The CRC unit 212 performs error detection on the downlink data received from the data decoding unit 211 using CRC, and outputs the error detection result to the ACK / NACK generation unit 214. Further, the CRC unit 212 outputs the downlink data determined as no error as a result of the error detection as the received data.

The control unit 213 holds in advance information about the PUCCH resource notified from the base station 100 to the terminal 200 by the broadcast signal, the PDCCH signal or the upper layer signaling, and the information about the repetition level.

The control unit 213 uses the information about the PUCCH resource and the identification information of the CCE received from the determination unit 209, and the PUCCH resource (frequency and the primary diffusion / secondary diffusion) corresponding to the CCE shown in the identification information of the CCE. The code used for) is specified. That is, the control unit 213 identifies the PUCCH resource of the uplink control channel based on the identification information of the CCE.

Specifically, the control unit 213 generates a ZAC series corresponding to the PUCCH resource to be used, determines the cyclic shift amount to be used based on the set cyclic shift amount, and determines the cyclic shift amount to be used, and the primary diffusion unit 216. Output to. Further, the control unit 213 outputs the orthogonal code sequence corresponding to the PUCCH resource to be used to the secondary diffusion unit 217. Further, the control unit 213 outputs the frequency resource (subcarrier) corresponding to the PUCCH resource to be used to the IFFT unit 218.

Further, when the own terminal is in the MTC coverage enhancement mode, the control unit 213 outputs information regarding the repetition level of PUCCH to the ACK / NACK generation unit 214.

The ACK / NACK generation unit 214 generates an ACK / NACK signal based on the error detection result received from the CRC unit 212. Specifically, the ACK / NACK generation unit 214 generates NACK when an error is detected, and generates ACK when an error is not detected. The ACK / NACK generation unit 214 outputs the generated ACK / NACK signal to the modulation unit 215. Further, when the own terminal is in the MTC coverage enhancement mode, the ACK / NACK generation unit 214 transmits a repetition signal according to the information regarding the repetition level received from the control unit 213. That is, when the repetition level of PUCCH is greater than 1, the ACK / NACK generation unit 214 transmits the same ACK / NACK signal to the modulation unit 215 over a plurality of consecutive subframes corresponding to the repetition level. Output.

The modulation unit 215 modulates the ACK / NACK signal received from the ACK / NACK generation unit 214, and outputs the modulated ACK / NACK signal to the primary diffusion unit 216.

The primary diffusion unit 216 primary diffuses the reference signal and the ACK / NACK signal received from the modulation unit 215 using the ZAC sequence and the cyclic shift amount set by the control unit 213, and ACK after the primary diffusion. The / NACK signal and the reference signal are output to the secondary spreading unit 217.

The secondary spreading unit 217 secondarily spreads the ACK / NACK signal and the reference signal using the orthogonal code sequence set by the control unit 213, and outputs the signal after the secondary spreading to the IFFT unit 218.

The IFFT unit 218 uses the frequency resource set by the control unit 213 to map the ACK / NACK signal and the reference signal received from the secondary diffusion unit 217 to subcarriers, and performs IFFT processing to perform time. Generate a region signal. The IFFT unit 218 outputs the generated signal to the CP addition unit 219.

The CP addition unit 219 adds a CP to the signal received from the IFFT unit 218, and outputs the signal after the CP addition to the transmission unit 220.

The transmission unit 220 performs RF processing such as D / A conversion and up-conversion on the signal received from the CP addition unit 219, and transmits the radio signal to the base station 100 via the antenna 201.

[Operation of base station 100 and terminal 200]
The operation of the base station 100 and the terminal 200 having the above configuration will be described.

In the following, a case where a terminal in the normal mode and a terminal in the MTC coverage enhancement mode coexist in the cell of the base station 100 will be described.

The base station 100 according to the present embodiment notifies each terminal 200 of information about the PUCCH resource in advance. The information about the PUCCH resource is, for example, the offset value used when specifying the PUCCH number from the CCE number, and the PUCCH resource code-multiplexed per one resource block (RB: Resource Block) arranged in each PUCCH area. Information about the maximum number of.

In the present embodiment, the offset value is set independently for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

Specifically, when the terminal in the normal mode receives the downlink allocation control information (PDCCH or EPDCCH), it is a PUCCH resource that transmits an ACK / NACK signal for the downlink data (PDSCH) indicated in the corresponding allocation control information. The resource number n _{PUCCH of} is determined according to the following equation.
n _PUCCH = n _CCE + N _PUCCH ⁽¹⁾ (1)

In formula (1), n _CCE indicates the CCE number (integer of 0 or more) occupied by PDCCH. Specifically, if the PDCCH occupies only one CCE, n _CCE is the number of that CCE. Also, if PUCCH occupies multiple CCEs, n _CCE is the smallest CCE number.

Further, in the equation (1), N _PUCCH ⁽¹⁾ indicates an offset value for specifying the PUCCH resource number from the CCE number. For example, in 3GPP Release 11, N _PUCCH ⁽¹⁾ indicates the number of PUCCH resources reserved for SPS / SR (Semi-Persistent Scheduling / Scheduling Request) resources. N _PUCCH ⁽¹⁾ is, for example, a common value in the cell, and is notified from the base station 100 to the terminal 200 by a broadcast signal or upper layer signaling.

The terminal in the normal mode determines the OC index and the cyclic shift amount actually used based on the determined PUCCH resource number n _PUCCH .

On the other hand, when the terminal in the MTC coverage enhancement mode receives the downlink allocation control information (PDCCH or EPDCCH), the PUCCH resource that transmits the ACK / NACK signal for the downlink data (PDSCH) indicated in the corresponding allocation control information. The resource number n _{PUCCH_MTC} is determined according to the following equation.
n _{PUCCH_MTC} = n _CCE + N _{PUCCH_MTC} ⁽¹⁾ (2)

In equation (2), N _{PUCCH_MTC} ⁽¹⁾ indicates an offset value for specifying the PUCCH resource number from the CCE number for the terminal in the MTC coverage enhancement mode. That is, an independent offset value N _{PUCCH_MTC} ⁽¹⁾ different from the offset N _PUCCH ⁽¹⁾ of the terminal in the normal mode is set for the terminal in the MTC coverage enhancement mode. N _{PUCCH_MTC} ⁽¹⁾ may be, for example, an individual value (UE specific) depending on the terminal 200, or a value common to terminals in the MTC coverage enhancement mode.

The terminal in the MTC coverage enhancement mode determines the OC index to be actually used and the cyclic shift amount based on the determined PUCCH resource number n _{PUCCH_MTC} .

FIG. 10 shows an example of PUCCH resources for a terminal in the normal mode and a terminal in the MTC coverage enhancement mode.

In FIG. 10, as in FIG. 3, 18 PUCCH resources out of a maximum of 36 PUCCH resources can be used for each 1 RB (PRB (Physical RB)). In FIG. 10, a PUCCH resource number (# 0 to # 53) is assigned to each of the 54 available PUCCH resources across the three RBs.

In FIG. 10, the offset value N _PUCCH ⁽¹⁾ = 6 for the terminal in the normal mode and the offset value N _{PUCCH_MTC} ⁽¹⁾ = 30 for the terminal in the MTC coverage enhancement mode.

That is, the terminal in the normal mode transmits an ACK / NACK signal using the PUCCH resource having the PUCCH resource number n _PUCCH = n _CCE +6. On the other hand, the terminal in the MTC coverage enhancement mode transmits an ACK / NACK signal using the PUCCH resource having the PUCCH resource number n _{PUCCH_MTC} = n _CCE +30.

That is, when the terminal 200 is a terminal in the normal mode, the terminal 200 transmits an ACK / NACK signal using the PUCCH resource in the PUCCH resource group for the terminal in the normal mode, and the terminal 200 transmits the MTC coverage. When the terminal is in the enhancement mode, the ACK / NACK signal is transmitted using the PUCCH resource in the PUCCH resource group for the terminal in the enhancement mode, which is different from the PUCCH resource group for the terminal in the normal mode.

Similarly, the base station 100 receives the ACK / NACK signal transmitted from the terminal in the normal mode by using the resources in the PUCCH resource group for the terminal in the normal mode, and the terminal in the MTC coverage enhancement mode. The ACK / NACK signal transmitted from is received by using the resources in the PUCCH resource group for the terminal in the MTC coverage enhancement mode, which is different from the PUCCH resource group for the terminal in the normal mode.

As a result, as shown in FIG. 10, a PUCCH resource group that can be used by the terminal in the MTC coverage enhancement mode to which the repetition transmission is applied to the PDCCH signal, the PDSCH signal, and the ACK / NACK signal to transmit the ACK / NACK signal. And, the terminal in the normal mode to which the repetition transmission is not applied is different from the PUCCH resource group that can be used to transmit the ACK / NACK signal. That is, the PUCCH resource area for both terminals is divided by making the offset value for specifying the PUCCH resource number from the CCE number different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

Note that FIG. 10 shows a case where the number of CCEs that can be used for the terminal 200 in each mode is 24. However, the number of CCEs that can be used for the terminal 200 in each mode is not limited to 24, and other values may be used, and the PUCCH resource area for the terminal 200 in each mode is divided according to the number of CCEs that can be used. As such, the offset values N _PUCCH ⁽¹⁾ and N _{PUCCH_MTC} ⁽¹⁾ may be set.

Here, as an example, as shown in FIG. 5, when the CCE number corresponding to the PUCCH resource used for the ACK / NACK signal transmitted in the same subframe is CCE # 0 (that is, n _CCE = 0). Will be described.

In this case, the terminal in the normal mode uses the PUCCH resource having the PUCCH resource number n _PUCCH = 6 (= 0 + 6) according to the equation (1).

On the other hand, the terminal in the MTC coverage enhancement mode uses the PUCCH resource having the PUCCH resource number n _{PUCCH_MTC} = 30 (= 0 + 30) according to the equation (2).

That is, when the own terminal is a terminal in the normal mode, the terminal 200 (control unit 213) adds the offset value N _PUCCH ⁽¹⁾ to the index n _CCE of the CCE used for the PDCCH, and actually ACKs. Calculate the PUCCH resource used for the / NACK signal. Further, when the terminal 200 is a terminal in the MTC coverage enhancement mode, the terminal 200 adds the offset value N _{PUCCH_MTC} ⁽¹⁾ to the index n _CCE of the CCE used for PDCCH, and actually _performs an ACK / NACK signal. Calculate the PUCCH resource used for. However, the offset value N _PUCCH ⁽¹⁾ and the offset value N _{PUCCH_MTC} ⁽¹⁾ are different.

Therefore, when both terminals transmit the ACK / NACK signal in the same subframe, the CCE number associated with the PUCCH resource to which the normal mode terminal transmits the ACK / NACK signal and the MTC coverage enhancement mode terminal ACK. Even if the CCE number associated with the PUCCH resource that sends the / NACK signal is the same CCE # 0, the PUCCH resource used by both is different.

That is, when both terminals transmit ACK / NACK signals in the same subframe, even if the CCE number (minimum index) used for the corresponding PDCCH is the same, the terminal in normal mode and the MTC coverage enhancement mode It is possible to avoid the collision of PUCCH resources with the terminal of.

As described above, according to the present embodiment, the PUCCH resource is determined by using different offset values for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. By doing so, the PUCCH resource that can be used by the terminal in the normal mode and the PUCCH resource that can be used by the terminal in the MTC coverage enhancement mode are separated. As a result, even if the CCE occupied by the PDCCH used to allocate the downlink data corresponding to the ACK / NACK signal transmitted in the same subframe is the same, the PUCCH resource used for the ACK / NACK signal is different. Can be made. Therefore, it is possible to avoid collision of PUCCH resources that transmit ACK / NACK signals.

Further, as described above, by making the offset value for specifying the PUCCH resource number different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode, the collision of the PUCCH resource is avoided, so that the PDCCH resource can be used. There is no need to add any restrictions on the allocation. Therefore, according to the present embodiment, the utilization efficiency of PDCCH resources does not decrease or the complexity of scheduling does not increase.

Therefore, according to the present embodiment, the collision of PUCCH resources between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode can be caused without reducing the frequency utilization efficiency of the PDCCH resource and increasing the complexity of scheduling. It can be avoided.

Further, the allocation of PUCCH resources to terminals in normal mode (see, eg, equation (1)) has already been done in the LTE system. Therefore, in the present embodiment, only the offset value N _{PUCCH_MTC} ^(1), which is independently used when allocating the PUCCH resource to the terminal in the MTC coverage enhancement mode, needs to be newly notified from the base station 100 to the terminal 200. Therefore, the influence on the operation of the existing system is small.

(Embodiment 2)
Since the basic configuration of the base station and the terminal according to the present embodiment is the same as that of the first embodiment, it will be described with reference to FIGS. 8 (base station 100) and 9 (terminal 200).

Hereinafter, as in the first embodiment, a case where the terminal in the normal mode and the terminal in the MTC coverage enhancement mode coexist in the cell of the base station 100 will be described.

The base station 100 according to the present embodiment notifies each terminal 200 of information about the PUCCH resource in advance. The information about the PUCCH resource is, for example, the offset value used when specifying the PUCCH number from the CCE number, and the PUCCH resource code-multiplexed per one resource block (RB: Resource Block) arranged in each PUCCH area. Information about the maximum number of.

In the present embodiment, the offset value is commonly set for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. However, the correspondence between the CCE number and the PUCCH resource number differs between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

Specifically, the terminal in the normal mode determines the resource number n _PUCCH of the PUCCH resource that transmits the ACK / NACK signal according to the equation (1), as in the first embodiment, and determines the OC index and the cyclic shift that are actually used. Determine the amount.

On the other hand, when the terminal in the MTC coverage enhancement mode receives the downlink allocation control information (PDCCH or EPDCCH), the PUCCH resource that transmits the ACK / NACK signal for the downlink data (PDSCH) indicated in the corresponding allocation control information. The resource number n _{PUCCH_MTC} is determined according to the following equation.
n _{PUCCH_MTC} = N _PUCCH ⁽¹⁾ -1-n _CCE (3)

In the equation (3), N _PUCCH ⁽¹⁾ is an offset value for specifying the PUCCH resource number from the CCE number, and is also a value included in the equation (1). That is, the same offset value N _PUCCH ^{(1) as} the offset N _PUCCH ⁽¹⁾ of the terminal in the normal mode is set for the terminal in the MTC coverage enhancement mode. N _PUCCH ⁽¹⁾ may be notified from the base station 100 to the terminal 200 by a broadcast signal or higher layer signaling, for example.

The terminal in the MTC coverage enhancement mode determines the OC index to be actually used and the cyclic shift amount based on the determined PUCCH resource number n _{PUCCH_MTC} .

That is, when the own terminal is a terminal in the normal mode, the terminal 200 (control unit 213) adds the offset value N _PUCCH ⁽¹⁾ to the index n _CCE of the CCE used for the PDCCH, and actually ACKs. Calculate the PUCCH resource used for the / NACK signal. On the other hand, when the terminal 200 is a terminal in the MTC coverage enhancement mode, the terminal 200 actually ACK / NACK by subtracting the index n _CCE of the CCE used for PDCCH from the offset value N _{PUCCH_MTC} ^(1). Calculate the PUCCH resource used for the signal.

FIG. 11 shows an example of PUCCH resources for a terminal in the normal mode and a terminal in the MTC coverage enhancement mode.

In FIG. 11, as in FIG. 10, 18 PUCCH resources out of a maximum of 36 PUCCH resources can be used for each RB. In FIG. 11, PUCCH resource numbers (# 0 to # 53) are assigned to each of the 54 available PUCCH resources across the three RBs.

Further, in FIG. 11, the offset value N _PUCCH ⁽¹⁾ = 30 for each terminal 200.

That is, the terminal in the normal mode transmits an ACK / NACK signal using the PUCCH resource having the PUCCH resource number n _PUCCH = n _CCE +30. On the other hand, the terminal in the MTC coverage enhancement mode transmits an ACK / NACK signal using the PUCCH resource having the PUCCH resource number n _{PUCCH_MTC} = 30-1-n _CCE (= 29-n _CCE ).

That is, as shown in FIG. 11, with the boundary between PUCCH resource numbers # 29 and # 30, PUCCH resources with numbers # 30 or higher are set in the PUCCH resource area for terminals in normal mode, and numbers # 29 or lower. PUCCH resource is set in the PUCCH resource area for terminals in MTC coverage enhancement mode.

As a result, as shown in FIG. 11, different PUCCH resource areas are set for each of the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. That is, by making the correspondence (formula (1) and formula (3)) for specifying the PUCCH resource number from the CCE number different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode, both of them are used. The PUCCH resource area for the terminal is divided.

Here, as an example, as shown in FIG. 5, when the CCE number corresponding to the PUCCH resource used for the ACK / NACK signal transmitted in the same subframe is CCE # 0 (that is, n _CCE = 0). Will be described.

In this case, the terminal in the normal mode uses the PUCCH resource having the PUCCH resource number n _PUCCH = 30 (= 0 + 30) according to the equation (1).

On the other hand, the terminal in the MTC coverage enhancement mode uses the PUCCH resource of PUCCH resource number n _{PUCCH_MTC} = 29 (= 29-0) according to the equation (3).

That is, when both terminals transmit ACK / NACK signals in the same subframe, the CCE number associated with the PUCCH resource to which the normal mode terminal transmits the ACK / NACK signal and the MTC coverage enhancement mode terminal ACK. Even if the CCE number associated with the PUCCH resource that sends the / NACK signal is the same CCE # 0, the PUCCH resource used by both is different.

That is, when both terminals transmit ACK / NACK signals in the same subframe, even if the CCE number (minimum index) used for the corresponding PDCCH is the same, the terminal in normal mode and the MTC coverage enhancement mode It is possible to avoid the collision of PUCCH resources with the terminal of.

As described above, according to the present embodiment, the PUCCH resource is determined for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode by using different CCE associations. By doing so, the PUCCH resource that can be used by the terminal in the normal mode and the PUCCH resource that can be used by the terminal in the MTC coverage enhancement mode are separated. As a result, even if the CCE occupied by the PDCCH used to allocate the downlink data corresponding to the ACK / NACK signal transmitted in the same subframe is the same, the PUCCH resource used for the ACK / NACK signal is different. Can be made. Therefore, it is possible to avoid collision of PUCCH resources that transmit ACK / NACK signals.

Further, as described above, the collision of PUCCH resources is avoided by making the correspondence for specifying the PUCCH resource number different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode, so that the PDCCH resource can be used. You don't need to add any restrictions on allocations. Therefore, according to the present embodiment, the utilization efficiency of PDCCH resources does not decrease or the complexity of scheduling does not increase.

Therefore, according to the present embodiment, the collision of PUCCH resources between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode can be caused without reducing the frequency utilization efficiency of the PDCCH resource and increasing the complexity of scheduling. It can be avoided.

Further, the allocation of PUCCH resources to terminals in normal mode (see, eg, equation (1)) has already been done in the LTE system. Also, when allocating PUCCH resources to a terminal in MTC coverage enhancement mode, the same parameters (offset value N _PUCCH ⁽¹⁾ ) as in the terminal in normal mode are used. Therefore, there are no new parameters to be added for terminals in MTC coverage enhancement mode. Therefore, it does not affect the operation of the existing system.

The mapping for specifying the PUCCH resource number from the CCE number may be reversed between the normal mode and the MTC coverage enhancement mode. That is, the terminal in the normal mode may determine the PUCCH resource number using the equation (3), and the terminal in the MTC coverage enhancement mode may determine the PUCCH resource number using the equation (1). Since it is assumed that the terminal does not communicate so frequently in MTC, it is assumed that the PUCCH area of the terminal in the MTC coverage enhancement mode is used infrequently. Further, in the uplink, a PUSCH area (Physical Downlink Shared Channel) is arranged at the center of the system band, PUCCH areas are arranged at both ends, and PUCCH resources (for example, see FIG. 11) are arranged from the outside to the inside of the PUCCH area. PUCCH resource numbers are assigned in ascending order toward. Therefore, the PUCCH region of the terminal in the MTC coverage enhancement mode, which is infrequently used and associated with the equation (1), is arranged in the frequency band inside the uplink, so that it is continuous with the frequency band for the uplink data. be able to. By doing so, when the terminal in the MTC coverage enhancement mode does not use the PUCCH resource, the resource can be used for the uplink data (PUSCH). In addition, since the PUCCH area of the terminal in MTC coverage enhancement mode is continuous with the PUSCH area, multiple continuous subcarriers can be collectively assigned to a specific terminal, and the peak-to-transmission power ratio (PAPR: Peak-to-) can be assigned. The increase in Average Power Ratio) can be suppressed.

(Embodiment 3)
Since the basic configuration of the base station and the terminal according to the present embodiment is the same as that of the first embodiment, it will be described with reference to FIGS. 8 (base station 100) and 9 (terminal 200).

In the following, a case where a terminal in the normal mode and a terminal in the MTC coverage enhancement mode coexist in the cell of the base station 100 will be described.

The base station 100 according to the present embodiment notifies each terminal 200 of information about the PUCCH resource in advance. Information about PUCCH resources can be found, for example, by the difference in the amount of cyclic shift between adjacent available PUCCH resources in one orthogonal sequence of PUCCH resources (see, eg, FIG. 3) and per RB placed in each PUCCH region. Contains information about the maximum number of PUCCH resources to be code-multiplexed.

In addition, different PUCCH resource areas are set for each of the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. In the following description, the case of notifying Implicit in association with the CCE number as the allocation of PUCCH resources to the terminal in the MTC coverage enhancement mode will be described. For example, the PUCCH resource for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode may be set by the same method as in the first embodiment or the second embodiment. However, in the present embodiment, as the allocation of PUCCH resources to the terminal in the MTC coverage enhancement mode, the base station 100 may Explicitly notify the terminal 200 by using upper layer signaling or the like.

In the present embodiment, the difference in the patrol shift amount is set independently for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode.

FIG. 12 shows an example of PUCCH resources for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode according to the present embodiment. In FIG. 12, out of a total of 72 PUCCH resources of the two RBs, 12 PUCCH resources are reserved for SPS / SR, 48 PUCCH resources are reserved for the terminal in normal mode, and the rest. Twelve PUCCH resources are reserved for terminals in MTC coverage enhancement mode.

As described above, the PUCCH resource shown in FIG. 12 is defined by the combination of the orthogonal code sequence (OC index) and the cyclic shift amount (Cyclic shift Index) of the ZAC sequence.

In the terminal in the normal mode, the difference Δ _shift ^PUCCH of the cyclic shift amount between adjacent available resources in one orthogonal code sequence that defines the PUCCH resource is set. For example, in FIG. 12, Δ _shift ^PUCCH = 2 is set. That is, PUCCH resources corresponding to every other cyclic shift amount can be used for 12 cyclic shift amounts (Cyclic Shift Index = 0 to 11) that can be taken for one orthogonal code sequence. Therefore, 18 PUCCH resources out of a maximum of 36 PUCCH resources can be used for each RB (PRB (Physical RB)) for the terminal in the normal mode.

In FIG. 12, when the terminal in the normal mode receives the downlink allocation control information, the resource number n _PUCCH of the PUCCH resource that transmits the ACK / NACK signal for the downlink data shown in the corresponding allocation control information is expressed by the equation (1). ) May be determined (however, N _PUCCH ⁽¹⁾ = 6).

In FIG. 12, among the PUCCH resources in which the resources corresponding to every other cyclic shift amount in each orthogonal code sequence are numbered starting from the PUCCH resource # 0, the PUCCH resource numbers # 6 to # 29 are assigned. Twenty-four PUCCH resources are PUCCH resources that can be used by terminals in normal mode.

On the other hand, in the terminal in the MTC coverage enhancement mode, the difference Δ _shift ^PUCCH_MTC of the cyclic shift amount between adjacent available resources in one orthogonal code sequence defining the PUCCH resource is set. For example, in FIG. 12, Δ _shift ^PUCCH_MTC = 1 is set. That is, different parameters are set between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode as the difference in the amount of cyclic shift between the available PUCCH resources. Specifically, Δ _shift ^PUCCH_MTC is smaller than Δ _shift ^PUCCH .

That is, in the terminal in the MTC coverage enhancement mode, the PUCCH resource corresponding to all the continuous cyclic shift amounts for 12 cyclic shift amounts (Cyclic Shift Index = 0 to 11) that can be taken for one orthogonal code sequence is used. It will be possible.

In FIG. 12, when the terminal in the MTC coverage enhancement mode receives the downlink allocation control information, the resource number n _{PUCCH_MTC} of the PUCCH resource that transmits the ACK / NACK signal for the downlink data shown in the corresponding allocation control information is expressed. It may be determined according to (2) (however, N _{PUCCH_MTC} ⁽¹⁾ = 60).

In FIG. 12, 12 PUCCH resource numbers # 60 to # 71 are assigned to the resources corresponding to the continuous cyclic shift amounts in each orthogonal code sequence starting from PUCCH resource # 0. PUCCH resource becomes a PUCCH resource that can be used by terminals in MTC coverage enhancement mode.

The terminal 200 determines the OC index and the cyclic shift amount actually used based on the PUCCH resource number. The correspondence between the PUCCH resource number, the OC index, and the cyclic shift amount depends on the difference between the adjacent cyclic shift amounts. Therefore, in the present embodiment, the correspondence for specifying the OC index and the cyclic shift amount actually used from the PUCCH resource number is different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Specifically, the terminal of the MTC coverage enhancement mode, a delta _Shift ^PUCCH in equation showing association specifying the OC index and a cyclic shift amount for actual use from PUCCH resource numbers in the existing system (not shown) delta _Shift ^{It should work} by replacing it with ^PUCCH_MTC .

In the existing system (for example, 3GPP Release 11), the PUCCH resource for the terminal in the normal mode described above was secured. On the other hand, as shown in FIG. 12, when a terminal in the MTC coverage enhancement mode exists, the PUCCH resource for the terminal in the MTC coverage enhancement mode is additionally set in addition to the PUCCH resource for the terminal in the normal mode. Will be done.

Here, as shown in FIG. 12, the maximum code multiplexing possible number in each RB is specified by the number of available cyclic shift amounts among the possible cyclic shift amounts. Specifically, the maximum number of sign multiplexing is specified by how many cyclic shift amounts are available as PUCCH resources (that is, Δ _shift ^PUCCH and Δ _shift ^PUCCH_MTC ).

In the present embodiment, the maximum code multiplexing possible number (difference in the cyclic shift amount) is independently set for each of the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Specifically, among the combinations of the orthogonal code series and the cyclic shift amount defined as each resource of the PUCCH resource group for the terminal in the MTC coverage enhancement mode, the difference Δ of the adjacent cyclic shift amounts in the same orthogonal code sequence. _shift ^PUCCH_MTC is from the difference Δ _shift ^PUCCH of the adjacent cyclic shift amounts in the same orthogonal code series among the combinations of the orthogonal code series and the cyclic shift amount defined as each resource of the PUCCH resource group for the terminal in the normal mode. Is also small.

Therefore, in the PUCCH resource area for the terminal in the MTC coverage enhancement mode, the ratio of the available PUCCH resource to the entire PUCCH resource area is higher than that in the PUCCH resource area for the terminal in the normal mode. Specifically, as shown in FIG. 12, 24 PUCCH resources out of 48 PUCCH resources can be used in the terminal PUCCH resource area in the normal mode. On the other hand, in the PUCCH resource area for terminals in the MTC coverage enhancement mode, all 12 PUCCH resources can be used. That is, the maximum number of codes that can be multiplexed is maximized for the terminal in the MTC coverage enhancement mode.

That is, in the present embodiment, as described above, the maximum code multiplexing number in the PUCCH resource for the terminal in the MTC coverage enhancement mode is made larger than the maximum code multiplexing number in the PUCCH resource for the terminal in the normal mode. You can increase the number of PUCCH resources available to minimize the PUCCH resource overhead.

For example, in order to make 12 PUCCH resources available, it is necessary to secure 24 PUCCH resources when Δ _shift ^PUCCH_MTC = 2, whereas when Δ _shift ^PUCCH_MTC = 1, it is necessary to secure 24 PUCCH resources. As shown in FIG. 12, it is only necessary to secure 12 PUCCH resources. Thus, delta is made smaller than the _shift ^PUCCH_MTC Δ _shift ^PUCCH, as compared with the case where the same as the difference delta _Shift ^PUCCH cyclic shift amount set in the normal mode terminals, minimizing the PUCCH resource overhead It can be suppressed.

By the way, among PUCCH resources in the same RB, PUCCH resources that are not used for code multiplexing contribute to reduction of intersymbol interference by the intersymbol interference reduction effect due to code diffusion. For example, as shown in FIG. 12, in the PUCCH resource for the terminal in the normal mode, the PUCCH resource (PUCCH resource not used for intersymbol interference) that is not used between the adjacent resources of the available PUCCH resources # 6 to # 29 It exists and the PUCCH resource contributes to the reduction of intersymbol interference.

On the other hand, as shown in FIG. 12, in the PUCCH resource for the terminal in the MTC coverage enhancement mode, there is no PUCCH resource that is not used for code multiplexing.

However, considering the traffic characteristics of MTC, it is assumed that terminals with MTC do not communicate frequently. That is, the frequency of use of the PUCCH resource for the terminal in the MTC coverage enhancement mode is stochastically low. Therefore, in the PUCCH resource for terminals in the MTC coverage enhancement mode, even if the maximum number of code multiplexing possible in the same RB is increased, the number of terminals that can be code-multiplexed at the same time is small, so it corresponds to the amount of adjacent cyclic shifts in the same series. Resources are less likely to be used at the same time. That is, since the possibility of intersymbol interference due to the simultaneous use of resources corresponding to adjacent cyclic shift amounts is low, deterioration of the transmission characteristics of the ACK / NACK signal is unlikely to occur.

Also, considering the communication environment in MTC, it is assumed that the code rate of control information for the terminal in MTC coverage enhancement mode is set low, and the number of CCEs occupied by the L1 / L2 CCHs that make up the PDCCH is relatively large. Will be done. Therefore, for example, as described above, when the PUCCH resource number is implicitly notified by the CCE number to the terminal in the MTC coverage enhancement mode, the CCEs having adjacent numbers may be used for the same terminal. It gets higher. Therefore, it is less likely that PUCCH resources with adjacent numbers (resources corresponding to adjacent cyclic shift amounts) are used at the same time.

In this way, for terminals in MTC coverage enhancement mode, even if the difference in the amount of adjacent cyclic shifts is set smaller than in normal mode, PUCCH that increases the maximum number of code multiplexing within the same RB is increased. Since the actual usage probability in the resource area is low, the performance deterioration of the ACK / NACK signal due to the increase in the maximum number of code multiplexing is substantially not caused.

In this way, according to the present embodiment, the PUCCH resource uses the difference in the amount of cyclic shift (that is, the maximum number of code multiplexing) that is different between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Is set. As a result, in a system in which a terminal in the normal mode and a terminal in the MTC coverage enhancement mode coexist, the increase in the overhead of PUCCH resources can be minimized.

Furthermore, the allocation of PUCCH resources to terminals in normal mode has already been done in the LTE system. Therefore, in the present embodiment, the difference Δ _shift ^PUCCH_MTC of the cyclic shift amount independently used when allocating the PUCCH resource to the terminal in the MTC coverage enhancement mode may be newly notified from the base station 100 to the terminal 200. Therefore, the influence on the operation of the existing system is small.

Further, according to the present embodiment, the PUCCH resource for transmitting the ACK / NACK signal is transmitted by differentiating the PUCCH resource used for the ACK / NACK signal between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Collision can be avoided.

In this embodiment, the difference in the amount of cyclic shift (that is, the terminal that performs repetition) is different from that of the terminal in the normal mode (the terminal that does not perform repetition) and the terminal in the MTC coverage enhancement mode (the terminal that performs repetition). The case where the PUCCH resource is set using the maximum code multiplexing number) has been described. However, in the present embodiment, the difference in the amount of the cyclic shift (for example, the terminal under the macro base station and the terminal under the remote antenna station in the same cell) is different for each terminal group in the same cell (for example). That is, the PUCCH resource may be set using the maximum number of codes that can be multiplexed).

(Embodiment 4)
As described above, in the existing system, the CCE number and the PUCCH resource number are associated with each other on a one-to-one basis. That is, M PUCCH resources, which are the same number as the number of CCEs, are associated with M CCEs. For example, in FIG. 12, CCE # 0 and PUCCH # 60, CCE # 1 and PUCCH # 61, CCE # 2 and PUCCH # 62, ... Are associated with the terminal in the MTC coverage enhancement mode, respectively.

Further, it is assumed that the code rate of the control information is set low for the terminal in the MTC coverage enhancement mode in order to suppress the deterioration of the error rate characteristic of the control information. In other words, it is expected that the number of CCEs occupied by the L1 / L2 CCHs that make up the PDCCH for the terminal in the MTC coverage enhancement mode will be relatively large. For example, for a terminal in MTC coverage enhancement mode, a larger value (4,8) among the values (for example, 1,2,4,8) that can be taken as the number of occupied CCEs (sometimes called the aggregation level). ) Is expected to be set.

As mentioned above, when the L1 / L2 CCH occupies multiple CCEs in the PDCCH for the terminal in MTC coverage enhancement mode, the terminal corresponds to one CCE (CCE of the smallest index) among the multiple CCEs. Send ACK / NACK signals using resources. Therefore, the PUCCH resource corresponding to the CCE other than the CCE corresponding to the PUCCH resource used for transmitting the ACK / NACK signal is not used and is wasted. For example, in FIG. 12, when the L1 / L2 CCH constituting the PDCCH for the terminal in the MTC coverage enhancement mode occupies the four CCEs CCE # 0 to CCE # 3, the terminal has the smallest index among the four CCEs. The ACK / NACK signal is transmitted using only PUCCH # 60 corresponding to CCE # 0. That is, the physical resources of PUCCH # 61 to PUCCH # 63 corresponding to CCE # 1 to CCE # 3 are not used and are wasted.

Also, considering the traffic characteristics of MTC, it is assumed that terminals with MTC do not communicate frequently. That is, the frequency of use of PUCCH resources for terminals in the MTC coverage enhancement mode is stochastically low.

Therefore, in the present embodiment, instead of associating M PUCCH resources with M CCEs on a one-to-one basis for terminals in MTC coverage enhancement mode, M CCEs are associated with M resources. Associate fewer PUCCH resources. In other words, for a terminal in MTC coverage enhancement mode, multiple CCEs are associated with one PUCCH resource.

Since the basic configuration of the base station and the terminal according to the present embodiment is the same as that of the first embodiment, it will be described with reference to FIGS. 8 (base station 100) and 9 (terminal 200).

The base station 100 and the terminal 200 hold in advance the association between the CCE and the PUCCH resource according to the present embodiment.

Hereinafter, method 1 and method 2 relating to the association between the CCE and the PUCCH resource according to the present embodiment will be described.

In this embodiment, for example, as shown in FIG. 12, different PUCCH resource areas are set for each of the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. For example, the PUCCH resource for the terminal in the normal mode and the terminal in the MTC coverage enhancement mode may be set by the same method as in the first embodiment or the second embodiment. However, in the present embodiment, as the allocation of PUCCH resources to the terminal in the MTC coverage enhancement mode, the base station 100 may Explicitly notify the terminal 200 by using upper layer signaling or the like. Further, the difference in the amount of cyclic shift between the PUCCH resources available to the terminal in the MTC coverage enhancement mode is 1 as in the third embodiment (Δ _shift ^PUCCH_MTC = 1).

In the following, we will focus on PUCCH resources (# 60 to # 71) for terminals in MTC coverage enhancement mode.

<Method 1 (Fig. 13)>
Method 1 is a method in which the correspondence between the CCE number and the PUCCH resource is N to 1.

For example, FIG. 13 shows an example of the correspondence between the CCE number and the PUCCH resource number when N = 4.

As shown in FIG. 13, the four CCEs CCE # 0 to CCE # 3 are associated with PUCCH # 60, and the four CCEs CCE # 4 to CCE # 7 are associated with PUCCH # 61. , CCE # 8 to CCE # 11 are associated with PUCCH # 62.

For example, a terminal in MTC coverage enhancement mode has a PUCCH when the CCE with the smallest index among the CCEs that occupy the L1 / L2 CCHs that make up the PDCCH destined for its own terminal is one of CCE # 0 to CCE # 3. Send an ACK / NACK signal using resource # 60. Similarly, if the CCE with the smallest index among the CCEs assigned to terminals in MTC coverage enhancement mode is CCE # 4 to CCE # 7, PUCCH resource # 61 is used to transmit the ACK / NACK signal. In the case of CCE # 8 to CCE # 11, PUCCH resource # 62 is used to transmit the ACK / NACK signal.

For example, the PUCCH resource number n _{PUCCH_MTC} used by a terminal in MTC coverage enhancement mode is determined according to the following equation.
n _{PUCCH_MTC} = floor (n _CCE / N) + N _{PUCCH_MTC} ⁽¹⁾ (4)

In equation (4), the function "floor (X)" represents a floor function that returns the largest integer less than or equal to X. Further, n _CCE indicates the number of the smallest CCE among the CCEs occupied by the PDCCH, and N indicates the number of CCEs associated with one PUCCH resource (N = 4 in FIG. 13). In addition, N _{PUCCH_MTC} ⁽¹⁾ indicates the offset value for the terminal in MTC coverage enhancement mode. For example, in FIG. 13, N _{PUCCH_MTC} ⁽¹⁾ = 60.

According to the method 1, the PUCCH resource area reserved for the terminal in the MTC coverage enhancement mode is reduced to 1 / N as compared with the case where the CCE number and the PUCCH number are associated with each other on a one-to-one basis. Specifically, in the case of one-to-one correspondence between the CCE number and the PUCCH number, it was necessary to secure 12 PUCCH resources for 12 CCEs, whereas in the method 1, the figure In the case of 13 (when N = 4), only 3 PUCCH resources need to be secured for 12 CCEs.

<Method 2>
Method 2 is a method in which the number of CCEs associated with one PUCCH resource is set to a value that can be taken as the number of occupied CCEs (aggregation level).

For example, in method 2, it is assumed that the CCE occupancy number N (> 1) is set for the terminal in the MTC coverage enhancement mode.

For example, FIG. 14 shows an example of the correspondence between the CCE number and the PUCCH resource number when N = 4.

As shown in FIG. 14, the four CCEs CCE # 0 to CCE # 3 are associated with PUCCH # 60, and the four CCEs CCE # 4 to CCE # 7 are associated with PUCCH # 61. , CCE # 8 to CCE # 11 are associated with PUCCH # 62. That is, one PUCCH resource is associated with each CCE having N CCE occupancy.

CCEs are assigned to the terminals in the MTC coverage enhancement mode in units of four CCEs shown in FIG. For example, a terminal in MTC coverage enhancement mode uses PUCCH resource # 60 to send an ACK / NACK signal when the CCE occupying the L1 / L2 CCH that constitutes the PDCCH addressed to its own terminal is CCE # 0 to CCE # 3. Send. Similarly, when CCE # 4 to CCE # 7 are assigned to a terminal in MTC coverage enhancement mode, PUCCH resource # 61 is used to transmit the ACK / NACK signal, and CCE # 8 to CCE # 11 If assigned, PUCCH resource # 62 is used to send the ACK / NACK signal.

For example, the PUCCH resource number n _{PUCCH_MTC} used by a terminal in MTC coverage enhancement mode is determined according to the following equation.
n _{PUCCH_MTC} = n _CCE / N + N _{PUCCH_MTC} ⁽¹⁾ (5)

In the formula (5), n _CCE indicates the number of the smallest CCE among the CCEs occupied by the PDCCH, and N indicates the number of CCEs occupied for the terminal in the MTC coverage enhancement mode (N = 4 in FIG. 13). In addition, N _{PUCCH_MTC} ⁽¹⁾ indicates the offset value for the terminal in MTC coverage enhancement mode. For example, in FIG. 14, N _{PUCCH_MTC} ⁽¹⁾ = 60.

According to the method 2, the PUCCH resource area reserved for the terminal in the MTC coverage enhancement mode is reduced to 1 / N as compared with the case where the CCE number and the PUCCH number are associated with each other on a one-to-one basis. Specifically, in the case of one-to-one correspondence between the CCE number and the PUCCH number, it was necessary to secure 12 PUCCH resources for 12 CCEs, whereas in the method 2, the figure In the case of 14 (when N = 4), only 3 PUCCH resources need to be secured for 12 CCEs.

Further, since each PUCCH resource is associated with a CCE in the unit of the number of CCEs occupied by each terminal, N CCEs associated with one PUCCH resource are used simultaneously among a plurality of terminals. There is no.

The method 1 and the method 2 have been described above.

As described above, in the present embodiment, a plurality of CCEs are associated with one PUCCH resource for the terminal in the MTC coverage enhancement mode. As a result, it is possible to suppress an increase in the resources secured as PUCCH resources for the terminal in the MTC coverage enhancement mode. Therefore, even in a system in which a terminal in MTC coverage enhancement mode exists (when a PUCCH resource for a terminal in MTC coverage enhancement mode is additionally set), an increase in the overhead of the PUCCH resource can be suppressed.

Further, according to the present embodiment, the PUCCH resource for transmitting the ACK / NACK signal is transmitted by differentiating the PUCCH resource used for the ACK / NACK signal between the terminal in the normal mode and the terminal in the MTC coverage enhancement mode. Collision can be avoided.

(Embodiment 5)
If the PUCCH resource number is notified to Implicit in association with the CCE number between terminals in MTC coverage enhancement mode in the same way as in the existing system, if there are terminals with different PDCCH and PUCCH repetition levels, the same PUCCH resource ACK / NACK signals may be transmitted at the same time using, causing a collision of PUCCH resources.

FIG. 15 shows an example of a case where PUCCH resources collide between terminals in the MTC coverage enhancement mode. In FIG. 15, the repetition levels of PDCCH and PDSCH of terminal 1 (UE # 1) and terminal 2 (UE # 2) are N _PDCCH and N _PDSCH , respectively. Further, the repetition level of the PUCCH of the terminal 1 is N _PUCCH + α _PUCCH, and the repetition level of the PUCCH of the terminal 2 is N _PUCCH . That is, in terminal 1, N _PDCCH and N _PDSCH are the same as in terminal 2, and the repetition level of _PUCCH is higher by α _PUCCH .

Further, in FIG. 15, the terminal 1 transmits PDCCH from CCE # 0 using CCE # 3. On the other hand, the terminal 2 transmits the PDCCH from CCE # 0 to CCE # 3 from the next subframe after the PDCCH of the terminal 1 has been transmitted. That is, both the terminal 1 and the terminal 2 transmit the ACK / NACK signal using the PUCCH resource associated with CCE # 0.

As shown in FIG. 15, the terminal 1 transmits an ACK / NACK signal over the N _PUCCH + α _PUCCH subframe, and the terminal 2 is the next subframe in which the terminal 1 transmits the ACK / NACK signal over the N _PUCCH subframe. Sends an ACK / NACK signal from the frame across the N _PUCCH . Therefore, as shown in FIG. 15, PUCCH resources collide between terminals in the α _PUCCH subframe in the latter half of the PUCCH repetition of the terminal 1 and the subframe corresponding to the α _PUCCH subframe in the first half of the PUCCH repetition of the terminal 2. Resulting in.

Therefore, in the present embodiment, a method of avoiding collision of PUCCH resources that transmit ACK / NACK signals between terminals in the MTC coverage enhancement mode will be described.

Since the basic configuration of the base station and the terminal according to the present embodiment is the same as that of the first embodiment, it will be described with reference to FIGS. 8 (base station 100) and 9 (terminal 200).

Specifically, when the terminal 200 (terminal in MTC coverage enhancement mode) has different repetition levels between PDCCH and PUCCH, the CCE number (in PUCCH repetition, up to the same number of subframes as the repetition level of PDCCH) ( That is, the ACK / NACK signal is transmitted using the PUCCH resource notified to Implicit in association with the minimum CCE number).

On the other hand, the terminal 200 transmits an ACK / NACK signal using the PUCCH resource assigned to Explicit in the subframe exceeding the repetition level of PDCCH. The PUCCH resource is notified in advance from the base station 100 to the terminal 200.

FIG. 16 shows the transmission timing of each channel according to the present embodiment. In FIG. 16, as in FIG. 15, the repetition levels of PDCCH and PDSCH of terminal 1 (UE # 1) and terminal 2 (UE # 2) are set to N _PDCCH and N _PDSCH , respectively. Further, the repetition level of the PUCCH of the terminal 1 is N _PUCCH + α _PUCCH, and the repetition level of the PUCCH of the terminal 2 is N _PUCCH . Further, in FIG. 16, N _{PUC CH} is the same as N _{PDC CH} .

Further, in FIG. 16, the terminal 1 transmits PDCCH from CCE # 0 using CCE # 3. On the other hand, the terminal 2 transmits the PDCCH from CCE # 0 to CCE # 3 from the next subframe after the PDCCH of the terminal 1 has been transmitted.

In this case, as shown in FIG. 16, in the PUCCH repetition, the terminal 1 is the smallest of the CCEs used for the PDCCH up to the same number of N _PUCCH subframes as the N _PDCCH among the N _PUCCH + α _PUCCH subframes. The ACK / NACK signal is transmitted using the PUCCH resource associated with CCE # 0 having the index of.

On the other hand, the terminal 1 transmits an ACK / NACK signal using the PUCCH resource notified to Explicit after the α _PUCCH subframe exceeding the N _PUCCH subframe among the N _PUCCH + α _PUCCH subframes.

Further, as shown in FIG. 16, in the PUCCH repetition, the terminal 2 was used for PDCCH from the next subframe in which the terminal 1 transmitted the ACK / NACK signal to the N _PUCCH subframe to the N _PUCCH subframe. The ACK / NACK signal is transmitted using the PUCCH resource associated with CCE # 0, which has the smallest index among the CCEs.

That is, in FIG. 16, the α _PUCCH subframe in the latter half of the PUCCH repetition of the terminal 1 and the α _PUCCH subframe in the first half of the PUCCH repetition of the terminal 2 are different from each other in both the terminal 1 and the terminal 2. PUCCH resources are used. Therefore, the collision of PUCCH resources between the terminal 1 and the terminal 2 does not occur.

In this way, the terminal 200 is among the plurality of subframes in which the repetition transmission of the ACK / NACK signal is performed, and in the subframe below the repetition level of PDCCH, among the PUCCH resources for the terminal in the MTC coverage enhancement mode, the terminal 200 Use the PUCCH resource associated with the CCE used for the PDCCH to send the ACK / NACK signal, and for subframes that exceed the PDCCH repetition level, use one of the preset PUCCH resources to ACK. Send a / NACK signal.

By doing so, when there are terminals in MTC coverage enhancement mode with different repetition levels of PDCCH and PUCCH, ACK / NACK signals can be sent simultaneously between terminals in MTC coverage enhancement mode that transmitted PDCCH using the same CCE. Even if a subframe to be transmitted occurs, it is possible to prevent the PUCCH resources that transmit the ACK / NACK signal from colliding with each other.

The present embodiment may be combined with the operations of the first to fourth embodiments. That is, a method of applying the present embodiment to a method of avoiding a collision of PUCCH resources between terminals in MTC coverage enhancement mode and a method of avoiding a collision of PUCCH resources between a terminal in MTC coverage enhancement mode and a terminal in normal mode. Any of the first to fourth embodiments may be applied to the above.

(Embodiment 6)
In the fifth embodiment, terminals having different repetition levels of PDCCH and PUCCH have been described. On the other hand, in the present embodiment, a case where the repetition levels of PDCCH and PUCCH in each terminal are the same but the repetition levels between the terminals are different will be described.

In this case, if the PUCCH resource number is implicitly notified between the terminals in the MTC coverage enhancement mode in association with the CCE number in the same way as in the existing system, the ACK / NACK signal is output between the terminals using the same PUCCH resource. It is sent at the same time, and PUCCH resource conflicts may occur.

FIG. 17 shows an example of a case where PUCCH resources collide between terminals in the MTC coverage enhancement mode. In FIG. 17, the repetition level of PDCCH, PDSCH, and PUCCH of terminal 1 (UE # 1) is 8, and the repetition level of PDCCH, PDSCH, and PUCCH of terminal 2 (UE # 2) is 4.

Further, in FIG. 17, the terminal 1 transmits PDCCH from CCE # 0 using CCE # 3. On the other hand, the terminal 2 transmits the PDCCH from CCE # 0 to CCE # 3 from the next subframe after the PDCCH of the terminal 1 has completed transmission. That is, both the terminal 1 and the terminal 2 transmit the ACK / NACK signal using the PUCCH resource associated with CCE # 0.

As shown in FIG. 17, the terminal 1 receives the PDCCH over eight subframes and receives the PDSCH over the next eight subframes. On the other hand, the terminal 2 receives the PDCCH over four subframes from the next subframe after the terminal 1 has completed receiving the PDCCH, and receives the PDSCH over the next four subframes. That is, the terminal 1 and the terminal 2 have the same PDSCH reception completion timing (or ACK / NACK signal transmission start timing).

In this case, at the same timing, the terminal 1 transmits an ACK / NACK signal over 8 subframes, and the terminal 2 transmits an ACK / NACK signal over 4 subframes. Therefore, as shown in FIG. 17, PUCCH resources collide with each other in the four subframes of the first half of the PUCCH repetition of the terminal 1 and the subframes corresponding to all four subframes of the PUCCH repetition of the terminal 2. It ends up.

Therefore, in the present embodiment, a method of avoiding collision of PUCCH resources that transmit ACK / NACK signals between terminals in MTC coverage enhancement modes having different repetition levels will be described.

Since the basic configuration of the base station and the terminal according to the present embodiment is the same as that of the first embodiment, it will be described with reference to FIGS. 8 (base station 100) and 9 (terminal 200).

Specifically, the terminal 200 (terminal in MTC coverage enhancement mode) is a PUCCH resource that is implicitly notified to the CCE number (that is, the minimum CCE number) used for transmitting the PDCCH in the PUCCH repetition. Is used to transmit the ACK / NACK signal. However, the terminal 200 transmits an ACK / NACK signal using the PUCCH resource specified by using a different offset value for each set repetition level.

For example, the repeated tee Deployment level PUCCH resource numbers n _{PUCCH_MTC_4} in the case of 4 and,, PUCCH resource numbers n _{PUCCH_MTC_8} the case of the repeated tee Deployment level 8 is determined according to the following equation.
n _{PUCCH_MTC_4} = n _CCE + N _{PUCCH_MTC_4} ⁽¹⁾ (6)
n _{PUCCH_MTC_8} = n _CCE + N _{PUCCH_MTC_8} ⁽¹⁾ (7)

In the formulas (6) and (7), n _CCE indicates the CCE number (integer of 0 or more) occupied by PDCCH. Further, in the equations (6) and (7), N _{PUCCH_MTC_4} ⁽¹⁾ indicates an offset value for specifying the PUCCH resource number from the CCE number when the repetition level is 4, and N _{PUCCH_MTC_8} ⁽¹⁾ is The offset value for specifying the PUCCH resource number from the CCE number when the repetition level is 8 is shown.

Different values are set for N _{PUCCH_MTC_4} ⁽¹⁾ and N _{PUCCH_MTC_8} ⁽¹⁾ . In other words, the PUCCH resource available to the terminal 200 is divided into at least a PUCCH resource when the repetition level is 4 and a PUCCH resource when the repetition level is 8. That is, the PUCCH resource group that can be used by the terminal 200 is composed of a plurality of sub-resource groups for each repetition level of the ACK / NACK signal.

Here, the case where the repetition level is 4 or 8 will be described, but the repetition level is not limited to 4 or 8, and if another value can be taken, the offset value is similarly set for that value. Set.

FIG. 18 shows the transmission timing of each channel according to the present embodiment. In FIG. 18, as in FIG. 17, the repetition level of PDCCH, PDSCH, and PUCCH of terminal 1 (UE # 1) is 8, and the repetition level of PDCCH, PDSCH, and PUCCH of terminal 2 (UE # 2) is 4. Is. Further, in FIG. 18, terminal 1 transmits PDCCH from CCE # 0 using CCE # 3. On the other hand, the terminal 2 transmits the PDCCH from CCE # 0 to CCE # 3 from the next subframe after the PDCCH of the terminal 1 has been transmitted.

In this case, as shown in FIG. 18, in the PUCCH repetition, the terminal 1 outputs an ACK / NACK signal using the PUCCH resource of N _{PUCCH_MTC_8} ⁽¹⁾ + n _CCE = N _{PUCCH_MTC_8} ⁽¹⁾ according to the equation (6). Send. On the other hand, in the PUCCH repetition, the terminal 2 transmits an ACK / NACK signal using the PUCCH resource of N _{PUCCH_MTC_4} ⁽¹⁾ + n _CCE = N _{PUCCH_MTC_4} ⁽¹⁾ according to the equation (7).

As mentioned above, N _{PUCCH_MTC_4} ⁽¹⁾ and N _{PUCCH_MTC_8} ⁽¹⁾ are different from each other. Therefore, as shown in FIG. 18, in the four subframes of the first half of the PUCCH repetition of the terminal 1 and the subframes corresponding to all four subframes of the PUCCH repetition of the terminal 2, both the terminal 1 and the terminal 2 have each other. Different PUCCH resources are used. Therefore, a collision of PUCCH resources between the terminal 1 and the terminal 2 does not occur.

By doing so, even if a subframe that transmits PDCCH using the same CCE and simultaneously transmits ACK / NACK signals occurs between terminals in MTC coverage enhancement mode with different repetition levels, ACK / It is possible to prevent the PUCCH resources that transmit the NACK signal from colliding with each other.

The present embodiment may be implemented in combination with the operations of the first to fourth embodiments. That is, a method of applying the present embodiment to a method of avoiding a collision of PUCCH resources between terminals in MTC coverage enhancement mode and a method of avoiding a collision of PUCCH resources between a terminal in MTC coverage enhancement mode and a terminal in normal mode. Any of the first to fourth embodiments may be applied to the above.

The embodiments of the present disclosure have been described above.

In each of the above embodiments, the case where one aspect of the present disclosure is configured by hardware has been described as an example, but the present disclosure can also be realized by software.

Further, each functional block used in the description of each of the above embodiments is typically realized as an LSI which is an integrated circuit. These may be individually integrated into one chip, or may be integrated into one chip so as to include a part or all of them. Although it is referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of circuit cells inside the LSI may be used.

Furthermore, if an integrated circuit technology that replaces an LSI appears due to advances in semiconductor technology or another technology derived from it, it is naturally possible to integrate functional blocks using that technology. There is a possibility of applying biotechnology.

The terminal of the present disclosure determines the resources used for the response signal to the downlink data based on the control information indicating the allocation of the downlink data, the receiving unit that receives the downlink data, and the control information. The control unit includes a control unit for transmitting the response signal and a transmission unit for transmitting the response signal using the determined resource. In the transmission unit, the own terminal receives the control information, the downlink data, and the response signal. In the case of the first terminal to which the repetition transmission is applied, the response signal is transmitted using the resources in the first resource group, and the own terminal is the second terminal to which the repetition transmission is not applied. In the case of a terminal, the response signal is transmitted using a resource in a second resource group different from the first resource group.

In the terminal of the present disclosure, the control unit adds a first offset value to the index of the control channel element (CCE) used for the control information, and adds the first offset value to the response signal in the first resource group. The resource to be used is calculated, the index of the CCE used for the control information is added with the second offset value, the resource used for the response signal in the second resource group is calculated, and the resource is calculated. The first offset value and the second offset value are different.

In the terminal of the present disclosure, the control unit adds an offset value to the index of the control channel element (CCE) used for the control information, and is used for the response signal in the first resource group. The resource is calculated, and the index of the CCE used for the control information is subtracted from the offset value to calculate the resource used for the response signal in the second resource group.

In the terminal of the present disclosure, each resource of the first resource group and the second resource group is defined by a combination of the orthogonal code sequence and the cyclic shift amount, and is defined as each resource of the first resource group. The difference in the amount of cyclic shifts adjacent to each other in the same orthogonal code series among the above combinations is the amount of cyclic shifts adjacent to each other in the same orthogonal code series among the combinations defined as each resource of the second resource group. Less than the difference.

In the terminal of the present disclosure, one resource of the first resource group is associated with a plurality of control channel elements (CCEs) used for the control information.

In the terminal of the present disclosure, the plurality of CCEs are the number of CCEs occupied by the allocation information.

In the terminal of the present disclosure, the transmission unit is among the plurality of subframes in which the repetition transmission of the response signal is performed, and in the subframe equal to or less than the number of repetitions of the control information, among the first resource group. , The response signal is transmitted using the resource associated with the control channel element (CCE) used for the control information, and is preset in the subframe exceeding the repetition number of the control information. The response signal is transmitted using the resource.

In the terminal of the present disclosure, the first resource group is composed of a plurality of sub-resource groups for each repetition number of the response signal.

The base station of the present disclosure provides control information indicating the allocation of downlink data, a transmission unit for transmitting the downlink data, and resources used for a response signal to the downlink data based on the control information. It includes a control unit for determining and a receiving unit for receiving the response signal using the determined resource, and the receiving unit has repetition with respect to the control information, the downlink data, and the response signal. The response signal transmitted from the first terminal to which transmission is applied is received by using the resources in the first resource group, and the response transmitted from the second terminal to which the repetition transmission is not applied. The signal is received using a resource in a second resource group different from the first resource group.

The transmission method of the present disclosure includes control information indicating allocation of downlink data, a receiving process for receiving the downlink data, and resources used for a response signal to the downlink data based on the control information. A control step for determining and a transmission step for transmitting the response signal using the determined resource are included, and the transmission step is a repetition with respect to the control information, the downlink data, and the response signal. The first terminal to which the transmission is applied transmits the response signal using the resources in the first resource group, and the second terminal to which the repetition transmission is not applied is different from the first resource group. The response signal is transmitted using the resources in the second resource group.

The receiving method of the present disclosure includes control information indicating allocation of downlink data, a transmission step of transmitting the downlink data, and resources used for a response signal to the downlink data based on the control information. A control step for determining the control step and a reception step for receiving the response signal using the determined resource are included, and the reception step includes repetition for the control information, the downlink data, and the response signal. The response signal transmitted from the first terminal to which transmission is applied is received by using the resources in the first resource group, and the response transmitted from the second terminal to which the repetition transmission is not applied. The signal is received using a resource in a second resource group different from the first resource group.

One aspect of the present disclosure is useful for mobile communication systems.

100 Base station 200 Terminal 101,213 Control unit 102 Control signal generation unit 103 Control signal coding unit 104 Control signal modulation unit 105 Notification signal generation unit 106 Data coding unit 107 Retransmission control unit 108 Data modulation unit 109 Signal allocation unit 110, 218 IFFT section 111,219 CP addition section 112, 220 Transmission section 113 Antenna 114, 202 Receiver section 115, 203 CP removal section 116 PUCCH extraction section 117 Series control section 118 Reverse diffusion section 119 Correlation processing section 120, 209 Judgment section 204 FFT Part 205 Extraction unit 206 Notification signal reception unit 207 Control signal demodulation unit 208 Control signal decoding unit 210 Data demodulation unit 211 Data decoding unit 212 CRC unit 214 ACK / NACK generation unit 215 Modulation unit 216 Primary diffusion unit 217 Secondary diffusion unit

Claims (12)

A transmitter that transmits downlink control information and downlink data to a terminal,
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. A receiver that receives a response signal to the transmitted downlink data, and
Equipped with
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
When the coverage enhancement mode capable of transmitting the response signal over a plurality of subframes is set in the terminal, the difference in the cyclic shift amount is such that the coverage enhancement mode is set in the terminal. It is set independently of the difference in the cyclic shift amount when it is not set.
base station. A transmitter that transmits downlink control information and downlink data to a terminal,
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. A receiver that receives a response signal to the transmitted downlink data, and
Equipped with
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
The difference in the amount of the cyclic shift when the downlink control information capable of repeating transmission over a plurality of subframes in which the coverage enhancement mode is set is transmitted to the terminal is the case where the coverage enhancement mode is not set. It is set independently of the difference in the amount of the cyclic shift.
base station. In the coverage enhancement mode, the transmitter transmits the downlink control information by repetition over a plurality of subframes.
The base station according to claim 1 or 2. The correspondence in the coverage enhancement mode is different from the correspondence in the case where the coverage enhancement mode is not set.
The base station according to any one of claims 1 to 3. The difference in the cyclic shift amount in the coverage enhancement mode is different from the difference in the cyclic shift amount when the coverage enhancement mode is not set.
The base station according to any one of claims 1 to 4. In the coverage enhancement mode, the receiving unit receives the response signal that is repeatedly transmitted from the terminal over a plurality of subframes.
The base station according to any one of claims 1 to 5. In the coverage enhancement mode, the receiving unit receives the response signal after a predetermined number of subframes from the subframe in which the terminal received the downlink data.
The base station according to any one of claims 1 to 6. In the coverage enhancement mode, the transmitter transmits the downlink data by repetition over a plurality of subframes.
The base station according to any one of claims 1 to 7. The base station
A transmission process for transmitting downlink control information and downlink data to a terminal, and
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. A receiving process for receiving the transmitted response signal to the downlink data, and
Equipped with
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
When the coverage enhancement mode capable of transmitting the response signal over a plurality of subframes is set in the terminal, the difference in the cyclic shift amount is such that the coverage enhancement mode is set in the terminal. It is set independently of the difference in the cyclic shift amount when it is not set.
Communication method. The base station
A transmission process for transmitting downlink control information and downlink data to a terminal, and
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. A receiving process for receiving the transmitted response signal to the downlink data, and
Equipped with
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
The difference in the amount of the cyclic shift when the downlink control information capable of repeating transmission over a plurality of subframes in which the coverage enhancement mode is set is transmitted to the terminal is the case where the coverage enhancement mode is not set. It is set independently of the difference in the amount of the cyclic shift.
Communication method. Transmission processing to send downlink control information and downlink data to the terminal,
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. Reception processing for receiving the transmitted response signal to the downlink data,
Control and
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
When the coverage enhancement mode capable of transmitting the response signal over a plurality of subframes is set in the terminal, the difference in the cyclic shift amount is such that the coverage enhancement mode is set in the terminal. It is set independently of the difference in the cyclic shift amount when it is not set.
Integrated circuit. Transmission processing to send downlink control information and downlink data to the terminal,
From the terminal using a combination of one of a plurality of orthogonal code sequences and one of a plurality of cyclic shift amounts identified from the association with the uplink control channel resource determined based on the control information. Reception processing for receiving the transmitted response signal to the downlink data,
Control and
The association is based on the difference in the amount of adjacent cyclic shifts combined in one Walsh-Hadamard sequence.
The difference in the amount of the cyclic shift when the downlink control information capable of repeating transmission over a plurality of subframes in which the coverage enhancement mode is set is transmitted to the terminal is the case where the coverage enhancement mode is not set. It is set independently of the difference in the amount of the cyclic shift.
Integrated circuit.

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