JP2020061778A - Base station, receiving method, and integrated circuit - Google Patents

Abstract

To ensure a running time while preventing a deterioration in transmission characteristic of an uplink signal.SOLUTION: A base station comprises: a control unit that, when a first narrow band used in a first sub frame that receives a first channel and a second narrow band used in a second sub frame that continues from the first sub frame and receives a second channel are different from each other, punctures two symbols and sets as a returning time; and a receiving unit that receives the first channel and second channel. When the first channel and second channel are a PUSCH (physical uplink shared channel), punctures the last one symbol in the first sub frame and the first one symbol in the second sub frame, and when the first channel is a PUSCH and the second channel is a PUCCH (physical uplink control channel), punctures the last two symbols in the first sub frame.SELECTED DRAWING: Figure 9

Description

  The present disclosure relates to a base station, a reception method, and an integrated circuit.

  In 3GPP LTE (3rd Generation Partnership Project Long Term Evolution), OFDMA (Orthogonal Frequency Division Multiple Access) is adopted, and SC-FDMA (Single Carrier-Frequency Division Multiple Access) is adopted as an uplink communication method from a terminal to a base station (for example, refer to Non-Patent Documents 1-3).

  In LTE, a base station performs communication by allocating a resource block (RB: Resource Block) within a system band to a terminal for each time unit called a subframe. FIG. 1 shows an example of a subframe structure of an LTE uplink shared channel (PUSCH: Physical Uplink Shared Channel). As shown in FIG. 1, one subframe is composed of two time slots. A plurality of SC-FDMA data symbols and a demodulation reference signal (DMRS) are time-multiplexed in each slot. Upon receiving PUSCH, the base station performs channel estimation using DMRS. After that, the base station demodulates / decodes SC-FDMA data symbols using the channel estimation result.

  Further, in LTE, HARQ (Hybrid Automatic Repeat Request) is applied to downlink data. That is, the terminal feeds back a response signal indicating an error detection result of downlink data to the base station. The terminal performs a CRC (Cyclic Redundancy Check) on the downlink data, and if there is no error in the CRC calculation result, an acknowledgment (ACK: Acknowledgement), and if there is an error in the CRC calculation result, a negative acknowledgment (NACK: Negative Acknowledgment) is sent back to the base station as a response signal. For feedback of this response signal (that is, ACK / NACK signal), an uplink control channel such as PUCCH (Physical Uplink Control Channel) is used.

  A plurality of formats are used according to the situation when the terminal transmits the ACK / NACK signal on PUCCH. For example, when there is no control information to be transmitted other than the ACK / NACK signal and the uplink scheduling request, PUCCH format 1a / 1b is used. On the other hand, when the transmission of the ACK / NACK signal and the feedback of the CSI (Channel State Information) that is periodically transmitted on the uplink overlap, PUCCH format 2a / 2b is used.

  Multiple ACK / NACK signals transmitted from multiple terminals in PUCCH format 1a / 1b are spread by a ZAC (Zero Auto-correlation) sequence having a Zero Auto-correlation characteristic on the time axis as shown in FIG. (Multiplied by ZAC sequence) and code-multiplexed in PUCCH. In FIG. 2, (W (0), W (1), W (2), W (3)) represents a Walsh sequence with a sequence length of 4, and (F (0), F (1), F (2)) represents a DFT (Discrete Fourier Transform) sequence with a sequence length of 3.

  As shown in FIG. 2, in a terminal, an ACK / NACK signal is first spread on the frequency axis by a ZAC sequence (sequence length 12) to frequency components corresponding to 1SC-FDMA symbols. That is, the ZAC sequence having a sequence length of 12 is multiplied by the ACK / NACK signal component represented by a complex number. Next, the ACK / NACK signal after primary spreading and the ZAC sequence as the reference signal are a Walsh sequence (sequence length 4: W (0) to W (3)) and a DFT sequence (sequence length 3: F, respectively). (0) to F (2)) causes secondary diffusion. That is, an orthogonal code sequence (OCC: Orthogonal Cover Code, Walsh sequence or DFT sequence) is added to each component of a signal having a sequence length of 12 (ACK / NACK signal after primary spreading or ZAC sequence as a reference signal). ) Are multiplied. Further, the second-spread signal is converted into a signal having a sequence length of 12 on the time axis by an inverse discrete Fourier transform (IDFT: Inverse Discrete Fourier Transform or IFFT). Then, a cyclic prefix (CP: Cyclic Prefix) is added to each of the signals after the IFFT to form a signal of one slot composed of seven SC-FDMA symbols.

  Further, as shown in FIG. 3, PUCCH is assigned to each terminal in subframe units.

  ACK / NACK signals from different terminals are spread using ZAC sequences defined by different cyclic shift amounts (Cyclic Shift Index) or orthogonal code sequences corresponding to different sequence numbers (OC Index: Orthogonal Cover Index). Has been (multiplied). The orthogonal code sequence is a set of Walsh sequence and DFT sequence. The orthogonal code sequence may also be referred to as a block-wise spreading code sequence. Therefore, the base station can separate these code-multiplexed ACK / NACK signals by using the conventional despreading and correlation processing (for example, see Non-Patent Document 4).

  By the way, in recent years, M2M (Machine-to-Machine) communication that realizes a service by autonomous communication between devices without relying on user's judgment is expected as a mechanism for supporting the future information society. There is a smart grid as a concrete application example of the M2M system. The smart grid is an infrastructure system that efficiently supplies lifelines such as electricity or gas. For example, a smart grid performs M2M communication between a smart meter installed in each home or building and a central server to autonomously and effectively adjust the resource demand balance. Other application examples of the M2M communication system include monitoring systems for article management, environmental sensing or telemedicine, and remote management of vending machine inventory or billing.

  In the M2M communication system, the use of a cellular system having a wide communication area has attracted attention. In 3GPP, in the standardization of LTE and LTE-Advanced, sophistication of a cellular network for M2M called Machine Type Communication (MTC) has been standardized (for example, Non-Patent Document 5) and low cost. Specifications are being pursued under the requirements of optimization, power consumption reduction, and coverage enhancement. In particular, unlike a handset terminal that is often used by a user while moving, it is an absolutely necessary condition for providing a service in a terminal such as a smart meter that hardly moves in order to provide a service. Therefore, even if the terminal (MTC terminal) corresponding to the location that cannot be used in the existing LTE and LTE-Advanced communication areas such as the basement of the building is installed, it is possible to further expand the communication area by "coverage expansion". (Extending MTC coverage) is an important issue to consider.

  In order to further expand the communication area, the “repeation” technique of repeatedly transmitting the same signal over a plurality of times is being considered for MTC coverage extension. In repetition, by combining signals transmitted by repetition on the transmission side, the received signal power is improved and the coverage (communication area) is expanded.

  In order to reduce the cost of terminals, the specifications of LTE-Advanced Release 13 (Rel. 13) are under study in MTC, and terminals (hereinafter sometimes referred to as MTC terminals) have a frequency band of 1.4 MHz. It only supports width (sometimes called narrow band or narrowband region). Therefore, “frequency hopping” is introduced in which a 1.4 MHz frequency band used by a terminal for transmission is hopped for each fixed subframe within the system band (for example, see Non-Patent Document 6). At the time of frequency hopping, a carrier frequency switching time (Retuning time) is required. It is considered that the Retuning time requires a maximum of about 2 symbols (see Non-Patent Document 7, for example).

3GPP TS 36.211 V12.7.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation (Release 12),” September 2015. 3GPP TS 36.212 V12.6.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding (Release 12),” September 2015. 3GPP TS 36.213 V12.7.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 12),” September 2015. 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. RP-141660, Ericsson, Nokia Networks, “New WI proposal: Further LTE Physical Layer Enhancements for MTC,” September 2014 R1-151454, MCC Support, “Final Report of 3GPP TSG RAN WG1 # 80 v1.0.0,” February 2015 R1-155051, RAN4, Ericsson, “Reply LS on retuning time between narrowband regions for MTC,” August 2015

  In the downlink, since the Rel.13 MTC terminal does not receive the existing LTE downlink control channel (PDCCH: Physical Downlink Control Channel), the 2 OFDM symbols at the beginning of the subframe, which is the area of the existing LTE PDCCH, are retuning time. It is possible to

  On the other hand, in the uplink, an MTC terminal of Rel. 13 can transmit PUSCH or PUCCH using all SC-FDMA symbols in a subframe, as in existing LTE terminals. Therefore, in order to apply frequency hopping to the MTC terminal, it is necessary to stop part of the PUSCH or PUCCH transmission at the time of retuning and secure a retuning time of about 2 SC-FDMA symbols.

The following four methods 1 to 4 will be described as methods for ensuring the uplink retuning time.
Method 1 (FIG. 4): 2SC at the end of one subframe immediately before Retuning-method of discarding (puncturing) the FDMA symbol and setting it as Retuning time Method 2 (FIG. 5): 2SC-at the beginning of one subframe immediately after Retuning Method for discarding FDMA symbol and setting it as Retuning time Method 3 (FIG. 6): Discarding the last 1SC-FDMA of one subframe immediately before Retuning and the first 1SC-FDMA symbol of one subframe immediately after Retuning and discarding the Retuning time Method 4 (FIG. 7): Method of providing guard subframe (1 subframe) for Retuning

  Among the methods for securing the above-mentioned Retuning time, Method 4 requires a Retuning time of one subframe each time frequency hopping is performed, so that all repetition transmission is performed compared to other methods 1 to 3. The time required to complete (or the number of subframes) increases and resource utilization efficiency decreases.

  For example, when the frequency hopping cycle is Y subframes, the resource utilization efficiency in method 4 is (Y-1) / Y. On the other hand, the resource utilization efficiency in methods 1 to 3 is (Y-1 + (12/14)) / Y. Therefore, for example, when Y = 4, the methods 1 to 3 can improve the resource utilization efficiency by about 28% as compared with the method 4.

  Then, in methods 1 to 3, there are the following two methods as formats for transmitting data in a Retuning subframe (a subframe in which 1 or 2 SC-FDMA symbols are used as Retuning time) at the time of PUSCH repetition.

  The first method is to puncture SC-FDMA symbols for retuning time after mapping data to 12 SC-FDMA symbols excluding DMRS as shown in FIG. 1 as with other subframes. . In this method, between Retuning subframes and other subframes, the same signal is transmitted on symbols other than SC-FDMA symbols punctured due to Retuning time, so in-phase combining is performed on the base station side. Can be easily realized.

  The second method is 10 or 11 SC-FDMA except the SC-FDMA symbol for the Retuning time as the format for transmitting data in the Retuning subframe, by changing the coding rate for the data from other subframes. This is a method of mapping data to symbols (Rate matching). Since this method is used in existing LTE that does not assume repetition transmission, it does not require modification from existing standards. However, since different signals are transmitted in each symbol between the Retuning subframe and other subframes, in-phase combining cannot be performed on the base station side.

  Since neither method has a large influence on data transmission in PUSCH, it is desirable to use methods 1 to 3 in PUSCH repetition from the viewpoint of resource utilization efficiency.

  Also, in PUCCH repetition, it is desirable to use methods 1 to 3 from the viewpoint of resource utilization efficiency and the commonality of operation between PUCCH and PUSCH. However, in methods 1 to 3, since a part of SC-FDMA symbols encoded by the orthogonal code sequence (OCC) is not used, the orthogonality between orthogonal sequences is broken, and the characteristics due to intersymbol interference occur. It may deteriorate.

  One aspect of the present disclosure is to provide a base station, a receiving method, and an integrated circuit that can secure Retuning time while suppressing deterioration of transmission characteristics of an uplink signal (PUSCH or PUCCH).

  A terminal according to an aspect of the present disclosure uses a plurality of orthogonal code sequences to spread a ACK / NACK signal for downlink data and a plurality of spreading ACK / NACK signals. Of the repetition unit, a signal allocation unit that maps the repeated ACK / NACK signal to a narrow band for MTC terminals, and the first subframe among the plurality of subframes When the narrow band used in the first sub-frame and the narrow band used in the second sub-frame continuous with the first sub-frame are different, the last two symbols of the first sub-frame or the first two symbols of the second sub-frame A puncturing control unit and a transmission unit for transmitting the ACK / NACK signal in the narrow band, each of the plurality of orthogonal code sequences is a subframe head. It is composed of a first partial sequence consisting of codes corresponding to two symbols and a second partial sequence consisting of codes corresponding to the last two symbols, and the first partial sequence and the second partial sequence are the plurality of orthogonal patterns. A configuration in which code sequences are partially orthogonal to each other is adopted.

  A terminal according to an aspect of the present disclosure, a spreading unit that spreads an ACK / NACK signal for downlink data, a repetition unit that repeats the spread ACK / NACK signal over a plurality of subframes, and the repeater. A signal allocator that maps the partitioned ACK / NACK signal to a narrow band for MTC terminals, a narrow band used in the first sub-frame of the plurality of sub-frames, and a contiguous sequence to the first sub-frame. When the narrow band used in the second subframe is different, a control unit that punctures the last 1 symbol of the first subframe and the first 1 symbol of the second subframe, and the ACK in the narrow band. / NACK signal transmitting section, the spreading section, the ACK / NACK signal mapped to the first subframe and the second subframe, Spreading using the Shortened PUCCH format, the transmitting unit transmits the ACK / NACK signal mapped in the first subframe according to the Shortened PUCCH format, and the ACK / NACK signal in the first subframe in the first 1 A configuration is used in which symbols other than symbols are used for transmission.

  A transmission method according to an aspect of the present disclosure spreads an ACK / NACK signal for downlink data using any one of a plurality of orthogonal code sequences, and distributes the spread ACK / NACK signal to a plurality of sub-codes. Repeating over a frame, mapping the repeated ACK / NACK signal to a narrow band for MTC terminals, and narrowing the narrow band used in the first sub-frame among the plurality of sub-frames and the first sub-frame. If the narrow band used in the second sub-frame continuous to the sub-frame is different, the last two symbols of the first sub-frame or the first two symbols of the second sub-frame are punctured and the ACK is sent in the narrow band. / NACK signal is transmitted, and each of the plurality of orthogonal code sequences corresponds to the first partial sequence consisting of codes corresponding to the first two symbols of the subframe and the last two symbols. Is composed of a second partial series consisting of codes, the first part sequence and the second partial series are respectively partially orthogonal between said plurality of orthogonal code sequences.

  A transmission method according to an aspect of the present disclosure spreads an ACK / NACK signal for downlink data, repeats the spread ACK / NACK signal over a plurality of subframes, and repeats the ACK / NACK signal. A signal is mapped to a narrow band for MTC terminals, and a narrow band used in the first sub-frame and a narrow band used in the second sub-frame that is continuous with the first sub-frame are included in the plurality of sub-frames. If different, punctures the last 1 symbol of the first subframe and the first 1 symbol of the second subframe, transmits the ACK / NACK signal in the narrowband, and transmits the ACK / NACK signal. The ACK / NACK signal mapped to the second subframe is spread using a Shortened PUCCH format to generate the ACK / NACK signal mapped to the first subframe. The ACK / NACK signal transmitted according to the Shortened PUCCH format and mapped in the second subframe is transmitted with symbols other than the first one symbol.

  Note that these comprehensive or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium, and any of the system, the apparatus, the method, the integrated circuit, the computer program, and the recording medium. It may be realized by any combination.

  According to one aspect of the present disclosure, it is possible to secure the retuning time while suppressing the deterioration of the transmission characteristics of the uplink signal (PUSCH or PUCCH).

  Further advantages and effects of one aspect of the present disclosure will be apparent from the specification and the drawings. Such advantages and / or effects are provided by the features described in several embodiments and in the description and drawings, respectively, but not necessarily all to obtain one or more of the same features. There is no.

Diagram showing an example of PUSCH subframe configuration Diagram showing an example of response signal generation processing in PUCCH Diagram showing an example of PUCCH format 1a / 1b subframe configuration Diagram showing setting example of Retuning time (method 1) Diagram showing example of Retuning time setting (method 2) Diagram showing example of Retuning time setting (method 3) Figure showing method of setting Retuning time (method 4) FIG. 3 is a block diagram showing the main 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 an example of the frequency hopping which concerns on Embodiment 1. The figure which shows an example of the frequency hopping which concerns on Embodiment 2. FIG. 5 is a diagram showing an example of ACK / NACK signal mapping according to the second embodiment. The figure which shows an example of the frequency hopping which concerns on Embodiment 3. The figure which shows an example of the frequency hopping which concerns on the modification of Embodiment 2 or 3. The figure which shows an example of the frequency hopping which concerns on Embodiment 4. The figure which shows an example of the frequency hopping which concerns on Embodiment 4. The figure which shows an example of the frequency hopping which concerns on Embodiment 5. The figure which shows an example of the frequency hopping which concerns on Embodiment 5. Diagram showing an example of PUCCH format 2 / 2a / 2b subframe configuration

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

[Outline of communication system]
The communication system according to each embodiment of the present disclosure includes, for example, a base station 100 and a terminal 200 compatible with the LTE-Advanced system. The terminal 200 is an MTC terminal.

  FIG. 8 is a block diagram showing a main configuration of terminal 200 according to each embodiment of the present disclosure. In terminal 200 shown in FIG. 8, spreading section 215 spreads an ACK / NACK signal for downlink data using any one of a plurality of orthogonal code sequences (OCC sequences). The repetition unit 216 repeats the spread ACK / NACK signal over a plurality of subframes. The signal allocation unit 217 maps the repeated ACK / NACK signal to a narrow band for MTC terminals. When the narrow band used in the first sub frame and the narrow band used in the second sub frame continuous to the first sub frame are different from each other among the plurality of sub frames (that is, when the retuning is performed) , The last two symbols of the first subframe or the first two symbols of the second subframe are punctured. The transmitter 220 transmits an ACK / NACK signal in a narrow band. Each of the plurality of orthogonal code sequences is composed of a first partial sequence consisting of codes corresponding to the first 2 symbols of the subframe and a second partial sequence consisting of codes corresponding to the last 2 symbols of the subframe. The first partial sequence and the second partial sequence are partially orthogonal between a plurality of orthogonal code sequences.

(Embodiment 1)
[Base station configuration]
FIG. 9 is a block diagram showing a configuration of base station 100 according to Embodiment 1 of the present disclosure. In FIG. 9, 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 data coding unit 105, a retransmission control unit 106, and data. Modulating section 107, signal allocating section 108, IFFT (Inverse Fast Fourier Transform) section 109, CP (Cyclic Prefix) adding section 110, transmitting section 111, antenna 112, receiving section 113, and CP removing section 114. An FFT (Fast Fourier Transform) unit 115, an extraction unit 116, a demapping unit 117, a channel estimation unit 118, an equalization unit 119, a demodulation unit 120, a decoding unit 121, a determination unit 122, The despreading unit 123, the correlation processing unit 124, and the determination unit 125 are included.

  The control unit 101 determines PDSCH and PUSCH allocation for the terminal 200. At this time, the control unit 101 determines the frequency allocation resource and the modulation / coding method to be instructed to the terminal 200, and outputs the information regarding the determined parameter to the control signal generation unit 102.

  Further, the control unit 101 determines the coding rate for the control signal and outputs the determined coding rate to the control signal coding unit 103. In addition, the control unit 101 determines a radio resource (downlink resource) to which the control signal and the downlink data are mapped, and outputs information regarding the determined radio resource to the signal allocation unit 108. Further, the control unit 101 determines a coding rate used when transmitting downlink data (transmission data) to the resource allocation target terminal 200, and outputs the determined coding rate to the data coding unit 105. .

  Further, the control unit 101 determines the coverage extension level of the terminal 200 (MTC terminal), and determines the information regarding the determined coverage extension level, or the number of repetitions required for PUSCH transmission or PUCCH transmission at the determined coverage extension level. , To the control signal generation unit 102 and the extraction unit 116. Further, the control unit 101 determines a frequency hopping method (frequency hopping On / Off, frequency hopping cycle, etc.) in PUSCH repetition transmission or PUCCH repetition transmission, and outputs information about the determined frequency hopping method to the control signal generation unit 102. Output to.

  Further, the control unit 101 determines resources (cyclic shift, orthogonal code sequence, frequency) for the terminal 200 to transmit PUCCH. The control unit 101 outputs the cyclic shift amount (ZAC sequence) and the orthogonal code sequence, which may be used for PUCCH transmission, to the despreading unit 123 and the correlation processing unit 124, and the frequency used for PUCCH transmission. The information about the resource is output to the extraction unit 116. Information regarding these PUCCH resources may be notified Implicitly to the terminal 200, or may be notified to the terminal 200 (a control unit 209 described later) by signaling of an upper layer unique to the terminal 200.

  The control signal generation unit 102 generates a control signal for the terminal 200. The control signal includes a cell-specific upper layer signal, a terminal-specific upper layer signal, an uplink grant instructing PUSCH allocation, or downlink allocation information instructing PDSCH allocation.

  The uplink grant is composed of a plurality of bits, and includes information indicating a frequency allocation resource, a modulation / coding method, and the like. Further, the uplink grant may include information about the coverage extension level or information about the number of repetitions required for PUSCH transmission.

  The downlink allocation information is composed of a plurality of bits and includes information indicating a frequency allocation resource, a modulation / coding system, and the like. The downlink allocation information may also include information on coverage extension level or information on the number of repetitions required for PUCCH transmission.

  The control signal generation unit 102 uses the control information input from the control unit 101 to generate a control information bit string, and outputs the generated control information bit string (control signal) to the control signal coding unit 103. Since the control information may be transmitted to a plurality of terminals 200, the control signal generation unit 102 generates a bit string by including the terminal ID of each terminal 200 in the control information for each terminal 200. For example, CRC (Cyclic Redundancy Check) bits masked by the terminal ID of the destination terminal are added to the control information.

  The control signal encoding unit 103 encodes the control signal (control information bit string) received from the control signal generating unit 102 according to the encoding rate instructed by the control unit 101, and outputs the encoded control signal to the control signal modulating unit 104. Output to.

  Control signal modulation section 104 modulates the control signal received from control signal coding section 103, and outputs the modulated control signal (symbol sequence) to signal allocation section 108.

  The data coding unit 105 performs error correction coding such as turbo coding on transmission data (downlink data) according to the coding rate received from the control unit 101, and sends the coded data signal to the retransmission control unit 106. Output.

  Retransmission control section 106 holds the coded data signal received from data coding section 105 and outputs it to data modulation section 107 at the time of initial transmission. Retransmission control section 106 holds the encoded data signal for each destination terminal. Further, upon receiving NACK for the transmitted data signal from determination section 125, retransmission control section 106 outputs corresponding held data to data modulation section 107. Retransmission control section 106, upon receiving an ACK for the transmitted data signal from determination section 125, deletes the corresponding held data.

  Data modulation section 107 modulates the data signal received from retransmission control section 106 and outputs the data modulation signal to signal allocation section 108.

  The signal allocation unit 108 maps the control signal (symbol sequence) received from the control signal modulation unit 104 and the data modulation signal received from the data modulation unit 107 onto the radio resource instructed by the control unit 101. The control channel to which the control signal is mapped may be a PDCCH (downlink control channel) for MTC or an EPDCCH (Enhanced PDCCH). The signal allocating unit 108 outputs the signal of the downlink subframe including the PDCCH or EPDCCH for MTC to which the control signal is mapped, to the IFFT unit 109.

  The IFFT unit 109 transforms the frequency domain signal into a time domain signal by performing IFFT processing on the signal received from the signal allocation unit 108. IFFT section 109 outputs the time domain signal to CP adding section 110.

  CP adding section 110 adds a CP to the signal received from IFFT section 109 and outputs the signal after the CP addition (OFDM signal) to transmitting section 111.

  The transmission unit 111 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 110, and wirelessly transmits it to the terminal 200 via the antenna 112. Send a signal.

  The receiving unit 113 performs RF processing such as down conversion or A / D (Analog-to-Digital) conversion on the uplink signal (PUSCH or PUCCH) from the terminal 200 received via the antenna 112, The received signal thus obtained is output to CP removing section 114. The uplink signal (PUSCH or PUCCH) transmitted from terminal 200 includes a signal subjected to repetition processing over a plurality of subframes.

  CP removing section 114 removes the CP added to the received signal received from receiving section 113, and outputs the signal after CP removal to FFT section 115.

  FFT section 115 applies FFT processing to the signal received from CP removing section 114, decomposes it into a signal sequence in the frequency domain, and extracts a signal corresponding to a PUSCH or PUCCH subframe. The FFT unit 115 outputs the obtained signal to the extraction unit 116.

  The extraction unit 116 extracts the PUSCH or PUCCH based on the information regarding the PUSCH or PUCCH resource input from the control unit 101. Further, the extraction unit 116 combines PUSCHs or PUCCHs over a plurality of repetition-transmitted subframes by using information (repetition information) on repetition transmissions of PUSCHs or PUCCHs input from the control unit 101. The extraction unit 116 outputs the combined signal to the demapping unit 117.

  The demapping unit 117 extracts the PUSCH portion assigned to the terminal 200 from the signal received from the extracting unit 116. Further, demapping section 117 decomposes the extracted PUSCH of terminal 200 into DMRS and data symbols, outputs DMRS to channel estimation section 118, and outputs data symbols (SC-FDMA data symbols) to equalization section 119. To do. Further, demapping section 117 decomposes the PUCCH received from extracting section 116 into a DMRS and an ACK / NACK signal, outputs the DMRS to channel estimating section 118, and outputs the ACK / NACK signal to equalizing section 119.

  The channel estimation section 118 performs channel estimation using the DMRS input from the demapping section 117. Channel estimation section 118 outputs the obtained channel estimation value to equalization section 119.

  Equalization section 119 equalizes the SC-FDMA data symbol or ACK / NACK signal input from demapping section 117, using the channel estimation value input from channel estimation section 118. Equalization section 119 outputs the equalized SC-FDMA data symbols to demodulation section 120, and outputs the equalized ACK / NACK signal to despreading section 123.

  Demodulation section 120 applies IDFT to the SC-FDMA data symbols in the frequency domain input from equalization section 119, converts the signals into time domain signals (symbol sequences), and then performs data demodulation. Specifically, demodulation section 120 converts the symbol sequence into a bit sequence based on the modulation scheme instructed to terminal 200, and outputs the obtained bit sequence to decoding section 121.

  Decoding section 121 performs error correction decoding on the bit sequence input from demodulation section 120, and outputs the decoded bit sequence to determination section 122.

  The determination unit 122 performs error detection on the bit sequence input from the decoding unit 121. Error detection is performed using the CRC bit added to the bit sequence. If there is no error in the CRC bit determination result, the determination unit 122 extracts the received data and notifies the control unit 101 of ACK (not shown). On the other hand, if the result of the CRC bit determination is erroneous, the determination unit 122 notifies the control unit 101 of NACK (not shown).

  The despreading unit 123 uses the orthogonal code sequence received from the control unit 101 (orthogonal code sequence to be used by the terminal 200) to despread the signal corresponding to the ACK / NACK signal in the signal received from the equalization unit 119. Then, the despread signal is output to the correlation processing unit 124.

  Correlation processing section 124 obtains the correlation value between the ZAC sequence input from control section 101 (ZAC sequence that terminal 200 may use. Cyclic shift amount) and the signal input from despreading section 123, The correlation value is output to the determination unit 125.

  The determination unit 125 determines whether the ACK / NACK signal transmitted from the terminal 200 indicates ACK or NACK for the transmitted data, based on the correlation value received from the correlation processing unit 124. The determination unit 125 outputs the determination result to the retransmission control unit 106.

[Terminal configuration]
FIG. 10 is a block diagram showing a configuration of terminal 200 according to Embodiment 1 of the present disclosure. In FIG. 9, terminal 200 has antenna 201, receiving section 202, CP removing section 203, FFT section 204, extracting section 205, data demodulating section 206, data decoding section 207, CRC section 208, The control unit 209, the data encoding unit 210, the CSI signal generation unit 211, the response signal generation unit 212, the modulation unit 213, the DFT unit 214, the spreading unit 215, the repetition unit 216, and the signal allocation 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 wireless signal (PDCCH or EPDCCH for MTC) and the data signal (PDSCH) from the base station 100 received via the antenna 201, Obtain a baseband OFDM signal. The receiving unit 202 outputs the OFDM signal to the CP removing unit 203.

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

  The FFT unit 204 transforms 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 the frequency domain signal to the extraction unit 205.

  The extraction unit 205 extracts the PDCCH or EPDCCH for MTC from the frequency domain signal received from the FFT unit 204, performs blind decoding on the PDCCH or EPDCCH for MTC, and attempts to decode the control signal addressed to itself. The CRC masked by the terminal ID of the terminal 200 is added to the control signal addressed to the terminal 200. Therefore, the extraction unit 205 extracts the control information and outputs it to the control unit 209 if the result of the blind decoding is that the CRC determination is OK. Further, the extraction unit 205 extracts downlink data (PDSCH signal) from the signal received from the FFT unit 204 and outputs it to the data demodulation unit 206.

  The data demodulation unit 206 demodulates the downlink data received from the extraction unit 205 and outputs the demodulated downlink data to the data decoding unit 207.

  The data decoding unit 207 decodes the downlink data received from the data demodulation unit 206, and outputs the decoded downlink data to the CRC unit 208.

  CRC section 208 performs error detection on the downlink data received from data decoding section 207 using CRC, and outputs the error detection result to response signal generation section 212. Further, CRC section 208 outputs downlink data, which is determined to be error-free as a result of error detection, as received data.

  The control unit 209 controls PUSCH transmission based on the control signal input from the extraction unit 205. Specifically, the control unit 209 instructs the signal allocation unit 217 to allocate resources at the time of PUSCH transmission, based on the PUSCH resource allocation information included in the control signal. Further, the control unit 209 instructs the data coding unit 210 and the modulation unit 213, respectively, on the coding system and the modulation system during PUSCH transmission based on the information on the coding system and the modulation system included in the control signal. Further, the control unit 209 determines the number of repetitions during PUSCH repetition transmission based on the information about the coverage extension level included in the control signal or the number of repetitions required for PUSCH transmission, and indicates the determined number of repetitions. The information is instructed to the repetition unit 216. Further, the control unit 209 instructs the repetition unit 216 to perform frequency hopping for PUSCH repetition based on the information regarding the frequency hopping method included in the control signal.

  The control unit 209 also controls PUCCH transmission based on the control signal input from the extraction unit 205. Specifically, the control unit 209 specifies the PUCCH resource (frequency, cyclic shift amount, and orthogonal code sequence) based on the information on the PUCCH resource included in the control signal, and allocates the specified information to the spreading unit 215 and the signal allocation. Instruct the section 217. Further, the control unit 209 determines the number of repetitions at the time of PUCCH repetition transmission based on the information about the coverage extension level or the information about the number of repetitions required for PUCCH transmission, and information indicating the determined number of repetitions, Instruct the repetition unit 216. Further, the control unit 209 instructs the repetition unit 216 to perform frequency hopping for PUCCH repetition based on the information regarding the frequency hopping method included in the control signal. Also, the control unit 209 instructs the spreading unit 215 about the transmission format of each subframe in PUCCH repetition.

  The data coding unit 210 adds CRC bits masked by the terminal ID of the terminal 200 to the input transmission data, performs error correction coding, and outputs the coded bit sequence to the modulation unit 213. .

  CSI signal generation section 211 generates CSI feedback information based on the CSI measurement result of terminal 200 and outputs the CSI feedback information to modulation section 213.

  The response signal generation unit 212 generates a response signal (ACK / NACK signal) for the received downlink data (PDSCH signal) based on the error detection result received from the CRC unit 208. Specifically, the response signal generator 212 generates NACK when an error is detected and ACK when no error is detected. The response signal generator 212 outputs the generated ACK / NACK signal to the modulator 213.

  Modulating section 213 modulates the bit sequence received from data encoding section 210 and outputs the modulated signal (symbol sequence) to DFT section 214. Further, modulator 213 modulates the CSI feedback information received from CSI signal generator 211 and the ACK / NACK signal received from response signal generator 212, and outputs the modulated signal (symbol sequence) to spreader 215. To do.

  The DFT unit 214 applies DFT to the signal input from the modulation unit 213 to generate a frequency domain signal, and outputs the frequency domain signal to the repetition unit 216.

  The spreading unit 215 uses the ZAC sequence defined by the cyclic shift amount set by the control unit 209 and the orthogonal code sequence to generate the reference signal and the CSI feedback information and ACK / NACK signal received from the modulation unit 213. The spread signal is output to the repetition unit 216. At this time, spreading section 215 spreads the ACK / NACK signal using the transmission format of each subframe in the PUCCH repetition set by control section 209.

  When the own terminal is in the MTC coverage extension mode, the repetition unit 216 distributes the signal input from the DFT unit 214 or the spreading unit 215 over a plurality of subframes based on the number of repetitions instructed by the control unit 209. Repeating and generating a repetition signal. The repetition unit 216 outputs the repetition signal to the signal allocation unit 217.

  The signal allocation unit 217 maps the signal received from the repetition unit 216 to the time / frequency resource of the PUSCH or PUCCH instructed by the control unit 209. The signal allocation unit 217 outputs the PUSCH or PUCCH signal to which the signal is mapped to the IFFT unit 218.

  The IFFT unit 218 generates a time domain signal by performing an IFFT process on the PUSCH signal or PUCCH signal in the frequency domain input from the signal allocation unit 217. The IFFT section 218 outputs the generated signal to the CP adding section 219.

  CP adding section 219 adds a CP to the time domain signal received from IFFT section 218, and outputs the signal after the CP addition to transmitting section 220.

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

[Operations of Base Station 100 and Terminal 200]
The operations of base station 100 and terminal 200 having the above configurations will be explained in detail.

  In the present embodiment, method 1 (FIG. 4) or method 2 (FIG. 5) is used among methods 1 to 4 for securing the above-mentioned Retuning time. That is, the terminal 200 (control unit 209) switches the narrow band to be used by frequency hopping, discards the trailing 2SC-FDMA data symbol of one subframe immediately before Retuning and sets it as Retuning time, or 1 immediately after Retuning. The first 2SC-FDMA data symbols of the subframe may be discarded to set Retuning time.

The base station 100 notifies the terminal 200 in advance of the number of _PUSCH repetitions (N _PUSCH ) or the number of PUCCH repetitions (N _PUCCH ) before transmitting / receiving the PUSCH or PUCCH. The repetition times N _PUSCH and N _PUCCH may be notified from the base station 100 to the terminal 200 via an upper layer specific to the terminal, or may be notified using the PDCCH for MTC.

  Also, the base station 100 notifies the terminal 200 in advance of the frequency hopping method (frequency hopping On / Off, frequency hopping cycle Y) before transmitting / receiving the PUSCH or PUCCH. The frequency hopping period Y may be notified from the base station 100 to the terminal 200 via a cell-specific upper layer as a cell-specific parameter, and as a terminal-specific parameter, the base station 100 may be terminal-specific to the terminal 200. May be notified via the upper layer of. Further, the frequency hopping period Y may be a predefined parameter in the standard.

Terminal 200 _{repeats PUSCH} or _PUCCH by the repetition count (N _PUSCH or N _PUCCH ) notified from base station 100.

Further, when frequency hopping is On, terminal 200 transmits a repetition signal in continuous Y subframes using the same resource when the number of repetitions (N _PUSCH or N _PUCCH ) is larger than Y, The terminal 200 changes the frequency band of 1.4 MHz used for transmitting the repetition signal (frequency hopping), and again transmits the repetition signal in continuous Y subframes using the same resource. When performing frequency hopping, terminal 200 secures Retuning time for 2SC-FDMA data symbols immediately before or immediately after Retuning according to Method 1 (FIG. 4) or Method 2 (FIG. 5).

<In case of PUSCH repetition>
At the time of PUSCH repetition, the terminal 200, in the Retuning subframe (one subframe immediately before Retuning in Method 1, one subframe immediately after Retuning in Method 2), the 12SC-FDMA data symbols excluding DMRS (for example, see FIG. 2SC-FDMA data symbols for retunin time (the last two symbols in Method 1 and the first two symbols in Method 2) are punctured.

  Alternatively, the terminal 200 maps data on 10SC-FDMA data symbols other than 2SC-FDMA data symbols for DMRS and Retuning time in the Retuning subframe (Rate matching).

<In case of PUCCH repetition>
During PUCCH repetition, terminal 200 maps an ACK / NACK signal and a reference signal in a Retuning subframe using a normal PUCCH format, and then maps 2SC-FDMA symbols for Retuning time. Puncture.

  FIG. 11 shows how frequency hopping is performed in PUCCH repetition when method 1 and Y = 4. As shown in FIG. 11, when terminal 200 transmits the repetition signal in Y = 4 subframes in succession, terminal 200 changes the frequency band by frequency hopping, and again transmits the repetition signal in 4 subframes. In method 1, terminal 200 punctures the 2SC-FDMA symbol immediately before Retuning (that is, at the end) in one subframe immediately before Retuning.

  Also, in the present embodiment, terminal 200 limits the number of orthogonal code sequence candidates used for spreading ACK / NACK signals to two.

  For example, the terminal 200 uses (W (0), W (1), W (2), W (3)) = (1, 1, 1, 1) and (1, -1 as candidates for the orthogonal code sequence. , 1, -1), or (W (0), W (1), W (2), W (3)) = (1, 1, 1, 1) and (1, -1 , -1, 1), the orthogonal code sequence used for spreading the ACK / NACK signal is set.

  Here, the partial sequence (1, 1) consisting of the first two codes of the orthogonal code sequence (1, 1, 1, 1) is the first two codes of the orthogonal code sequence (1, -1, 1, -1). Of the orthogonal code sequence (1, -1, -1, -1) and the partial sequence (1, -1) of the first half of the orthogonal code sequence (1, -1, -1). The partial sequence (1, 1) consisting of the latter two codes of the orthogonal code sequence (1, 1, 1, 1) is the latter two codes of the orthogonal code sequence (1, -1, 1, -1). And the partial sequence (-1, 1) of the latter half of the orthogonal code sequence (1, -1, -1, 1).

  That is, the orthogonal code sequence (1, 1, 1, 1) is partially orthogonal to the orthogonal code sequence (1, -1, 1, -1) and the orthogonal code sequence (1, -1, -1, 1). Among the orthogonal code sequences that are partially orthogonal to each other, among the four symbols corresponding to the sequence length, the sequence of the first two symbols (the sequence consisting of the first two codes) is orthogonal to each other, and the sequence of the second two symbols (the second half 2). Sequences consisting of one code) are also mutually orthogonal.

  That is, terminal 200 (spreading section 215) has a partial sequence consisting of codes corresponding to the first two symbols of the subframe (a sequence of the first two symbols) and a partial sequence consisting of codes corresponding to the last two symbols (the latter half). The ACK / NACK signal is spread using any of a plurality of orthogonal code sequences in which a sequence of 2 symbols) is partially orthogonal.

  By this means, base station 100 can separate the plurality of ACK / NACK signals code-multiplexed by the orthogonal code sequence into the first two symbols and the second two symbols. Therefore, even if the tail 2SC-FDMA symbol (method 1) or the head 2SC-FDMA symbol (method 2) is punctured and the signal is transmitted in the Retuning subframe, the orthogonal code sequences that are partially orthogonal to each other are orthogonal. There is no loss of sex. That is, even if either one of the first two symbols and the second two symbols of the four symbols corresponding to the sequence length is punctured, the other sequence does not lose orthogonality.

Here, for example, the orthogonal code sequence (OCC sequence) used in the existing LTE terminal is derived from the PUCCH resource number using the following equation.

In the formulas (1) to (3), n _OC represents an OCC sequence number, n _OC = 0 represents (1, 1, 1, 1), and n _OC = 1 represents (1, -1, 1, 1. -1), and n _OC = 2 represents (1, -1, -1, -1). Also, Δ _shift ^PUCCH indicates the difference between adjacent cyclic shift amounts, N _CS ⁽¹⁾ indicates the cyclic shift amount used for PUCCH format 1 / 1a / 1b, and N _SC ^RB indicates the number of subcarriers per RB. , N _PUCCH ⁽¹⁾ indicates the PUCCH resource number.

  Further, in the above equation, c = 3 represents the number of terminals that can be multiplexed with the orthogonal code sequence, that is, the number of candidates for the orthogonal code sequence that spreads the ACK / NACK signal. Therefore, in the present embodiment, terminal 200 to which frequency hopping is applied (MTC terminal) derives an OCC sequence from a PUCCH resource number with c = 2 in the above equation, and thereby spreads the ACK / NACK signal. The number of code sequence candidates can be limited to two.

  As described above, in the present embodiment, when frequency hopping is applied during uplink repetition transmission, terminal 200 punctures the trailing or leading 2SC-FDMA symbol in the Retuning subframe and transmits the signal. To do. At this time, terminal 200 limits the orthogonal code sequence that spreads the ACK / NACK signal in PUCCH to two orthogonal code sequences that are partially orthogonal. By doing so, the retuning time for changing the 1.4 MHz frequency band used by the terminal 200 for transmitting the repetition signal can be secured without causing the orthogonality to be broken due to the puncture. Therefore, according to the present embodiment, it is possible to secure the Retuning time while suppressing the deterioration of the transmission characteristics of the uplink signal (PUSCH or PUCCH).

(Embodiment 2)
The base station and terminal according to the present embodiment have the same basic configuration as base station 100 and terminal 200 according to Embodiment 1, and will be described with reference to FIGS. 9 and 10.

  In the present embodiment, Method 3 (FIG. 6) is used among Methods 1 to 4 for securing the above-mentioned Retuning time. That is, when switching the narrow band to be used by frequency hopping, terminal 200 (control section 209) has the last 1SC-FDMA data symbol of one subframe immediately before Retuning and the first 1SC-FDMA data symbol of one subframe immediately after Retuning. Discard and (puncture) and set Retuning time.

The base station 100 notifies the terminal 200 in advance of the number of _PUSCH repetitions (N _PUSCH ) or the number of PUCCH repetitions (N _PUCCH ) before transmitting / receiving the PUSCH or PUCCH. The repetition times N _PUSCH and N _PUCCH may be notified from the base station 100 to the terminal 200 via an upper layer specific to the terminal, or may be notified using the PDCCH for MTC.

  Also, the base station 100 notifies the terminal 200 in advance of the frequency hopping method (frequency hopping On / Off, frequency hopping cycle Y) before transmitting / receiving the PUSCH or PUCCH. The frequency hopping period Y may be notified from the base station 100 to the terminal 200 via a cell-specific upper layer as a cell-specific parameter, and as a terminal-specific parameter, the base station 100 may be terminal-specific to the terminal 200. May be notified via the upper layer of. Further, the frequency hopping period Y may be a predefined parameter in the standard.

Terminal 200 _{repeats PUSCH} or _PUCCH by the repetition count (N _PUSCH or N _PUCCH ) notified from base station 100.

Further, when frequency hopping is On, terminal 200 transmits a repetition signal in continuous Y subframes using the same resource when the number of repetitions (N _PUSCH or N _PUCCH ) is larger than Y, The terminal 200 changes the frequency band of 1.4 MHz used for transmitting the repetition signal (frequency hopping), and again transmits the repetition signal in continuous Y subframes using the same resource. When frequency hopping, terminal 200 secures Retuning time for 2SC-FDMA data symbols in one subframe immediately before Retuning and one subframe immediately after Retuning according to Method 3 (FIG. 6).

<In case of PUSCH repetition>
At the time of PUSCH repetition, the terminal 200 maps data to 12SC-FDMA data symbols (for example, refer to FIG. 1) excluding DMRS in a retuning subframe (one subframe immediately before retuning and one subframe immediately after retuning). After that, 2SC-FDMA data symbols for Retunin time (one SC-FDMA data symbol in each Retuning subframe) are punctured.

  Alternatively, the terminal 200 maps data in 11SC-FDMA data symbols other than 1SC-FDMA data symbols for DMRS and Retuning time in each Retuning subframe (Rate matching).

<In case of PUCCH repetition>
At the time of PUCCH repetition, terminal 200 spreads and maps the ACK / NACK signal in the first half Retuning subframe (one subframe immediately before Retuning) using the Shortened PUCCH format defined in Rel.12. After that, puncture the tail 1SC-FDMA symbol for Retuning time.

  On the other hand, the terminal 200 spreads an ACK / NACK signal in the latter half of the retuning subframe (one subframe immediately after retuning) using the Shortened PUCCH format defined in Rel. The spread ACK / NACK signal is mapped to the first 1 SC-FDMA symbol and the 7 SC-FDMA symbol excluding DMRS.

  That is, the terminal 200 (spreading unit 215) spreads the ACK / NACK signals mapped in the first and second Retuning subframes using the Shortened PUCCH format. Then, terminal 200 (transmitting section 220) transmits an ACK / NACK signal mapped according to the Shortened PUCCH format in the first half Retuning subframe, and transmits the ACK / NACK signal in the second half Retuning subframe other than the first one symbol. Send with the symbol.

  FIG. 12 shows a state of frequency hopping in PUCCH repetition when method 3 and Y = 4. As illustrated in FIG. 12, when the terminal 200 transmits the repetition signal in Y = 4 subframes in succession, the frequency band is changed by frequency hopping and the repetition signal is transmitted again in 4 subframes in succession. At this time, the terminal 200 punctures the 1SC-FDMA symbol at the tail of one subframe immediately before Retuning and the 1SC-FDMA data symbol at the beginning of one subframe immediately after Retuning.

  Also, as shown in FIG. 12, in the first half of the Retuning subframe, the ACK / NACK signal is spread and mapped using the Shortened PUCCH format. In the Shortened PUCCH format, in the first half slot of a subframe, an ACK / NACK signal is spread by a Walsh sequence with the same sequence length of 4 as in the Normal PUCCH format, and a DFT sequence of sequence length 3 is used in the latter half slot of the subframe. The ACK / NACK signal is spread. Therefore, in one subframe (14 symbols), the total number of symbols of the ACK / NACK signal (7 symbols) and DMRS (6 symbols) after spreading is 13 symbols. That is, by using the Shorted PUCCH format, one symbol at the end of one subframe is not used and can be secured as one symbol for Retuning time.

  On the other hand, as shown in FIG. 12, in the latter half of the retuning subframe, the ACK / NACK signal is spread using the Walsh sequence of sequence length 4 and the DFT sequence of sequence length 3 in the same manner as in the Shortened PUCCH format. The terminal 200 maps the spread ACK / NACK signal to the first SC-FDMA symbol for the retuning time and the 7SC-FDMA symbol excluding the DMRS (6 symbols). At this time, terminal 200 makes the mapping of the ACK / NACK signal after spreading in the second half Retuning subframe the same between terminals. By doing so, the base station 100 can separate a plurality of response signals code-multiplexed by the orthogonal code sequence (Walsh sequence and DFT sequence) in the latter half of the Retuning subframe.

  Next, a mapping method of the ACK / NACK signal after spreading in the latter half of the Retuning subframe will be described.

  FIG. 13 shows mapping examples 1 to 3 of the ACK / NACK signal.

  In mapping example 1, terminal 200 changes the order of ACK / NACK signals after spreading using the Shortened PUCCH format (inverts) and maps to the first 1SC-FDMA symbol and 7SC-FDMA symbol excluding DMRS. are doing.

  In Mapping Example 2, terminal 200 maps the ACK / NACK signals after spreading using the Shortened PUCCH format without changing the order of the first 1SC-FDMA symbol and 7SC-FDMA symbols excluding DMRS. That is, the symbols of the ACK / NACK signal after spreading are shifted by one symbol as compared with the mapping of the Shortened PUCCH format.

In mapping example 3, terminal 200 replaces the first half slot and the second half slot of the ACK / NACK signal after spreading using the Shorted PUCCH format, and then spreads the ACK / NACK signal (S ′ ₀ , S ′ ₀ , The order of S ′ ₁ and S ′ ₂ ) is exchanged (inverted) and mapped to the first 1SC-FDMA symbol and the 3SC-FDMA symbol excluding DMRS.

  The mapping method of the ACK / NACK signal after spreading in the Retuning subframe in the latter half has been described above. The mapping method of the ACK / NACK signal after spreading in the latter half of the Retuning subframe is not limited to the above mapping examples 1 to 3. It is sufficient that the mapping of the ACK / NACK signal of the latter half of the retuning subframe is the same between the terminals 200 to which code multiplexing is performed.

  Thus, in the present embodiment, in the first half of the Retuning subframe, since symbols that are not used for ACK / NACK signal and DMRS mapping in Shortened PUCCH format are used for Retuning time, orthogonality between orthogonal code sequences is provided. There is no loss of sex. Also, in the latter half of the retuning subframe, the ACK / NACK signal is spread in the same manner as the Shortened PUCCH format and mapped to symbols other than the first SC-FDMA data symbol and DMRS, so the orthogonality between orthogonal code sequences is broken. Does not occur. Therefore, the orthogonality between orthogonal code sequences does not collapse in each Retuning subframe.

  Further, in the present embodiment, since there is no limitation on the use of the orthogonal code sequence (OCC sequence), the maximum value of the number of terminals that can be multiplexed by the orthogonal code sequence is 3 (that is, equation (2) Can be maintained at c = 3).

(Embodiment 3)
The base station and terminal according to the present embodiment have the same basic configuration as base station 100 and terminal 200 according to Embodiment 1, and will be described with reference to FIGS. 9 and 10.

  In the present embodiment, Method 3 (FIG. 6) is used among Methods 1 to 4 for securing the above-mentioned Retuning time. That is, when switching the narrow band to be used by frequency hopping, terminal 200 (control section 209) has the last 1SC-FDMA data symbol of one subframe immediately before Retuning and the first 1SC-FDMA data symbol of one subframe immediately after Retuning. Discard and (puncture) and set Retuning time.

  The present embodiment differs from Embodiment 2 only in the processing for the ACK / NACK signal in one subframe immediately after Retuning (the latter half of the Retuning subframe). Therefore, here, the description of the operation before the transmission / reception of PUSCH or PUCCH and the operation at the time of PUSCH repetition is omitted.

  In this embodiment, at the time of PUCCH repetition, terminal 200 uses the Shortened PUCCH format defined in Rel.12 in the first half Retuning subframe (one subframe immediately before Retuning) and uses the ACK / NACK signal. , And then puncture the tail 1SC-FDMA symbol for Retuning time.

  On the other hand, the terminal 200 spreads the ACK / NACK signal in the latter half of the retuning subframe (one subframe immediately after the retuning) using the Shortened PUCCH format defined in Rel.12, and then the trailing 1SC-FDMA symbol. Puncture. Further, in the present embodiment, terminal 200 adds a timing offset of one symbol to the transmission timing of the second half Retuning subframe.

  FIG. 14 shows how frequency hopping is performed in PUCCH repetition when method 3 and Y = 4. As shown in FIG. 14, when terminal 200 transmits the repetition signal in Y = 4 consecutive subframes, terminal 200 changes the frequency band by frequency hopping and transmits the repetition signal again in four consecutive subframes. At this time, the terminal 200 punctures the 1SC-FDMA symbol at the tail of one subframe immediately before Retuning and the 1SC-FDMA data symbol at the beginning of one subframe immediately after Retuning.

  Further, as shown in FIG. 14, in the first half Retuning subframe, the ACK / NACK signal is mapped using the Shortened PUCCH format, as in the second embodiment. Therefore, as shown in FIG. 14, in the first half of the Retuning subframe, the tail 1SC-FDMA symbol in which the signal is not mapped in the Shortened PUCCH format can be reserved for the Retuning time.

  On the other hand, as shown in FIG. 14, in the second half of the retuning subframe, the ACK / NACK signal is spread using the Walsh sequence with a sequence length of 4 and the DFT sequence with a sequence length of 3 as in the Shortened PUCCH format. Also, the terminal 200 adds a timing offset of 1 SC-FDMA symbol to the transmission timing of the latter half of the Retuning subframe. As a result, as shown in FIG. 14, in the latter half of the Retuning subframe, the signal of Shortened PUCCH format is transmitted from the second symbol. By this means, the first 1SC-FDMA symbol of the latter half Retuning subframe can be secured for Retuning time. Further, in the latter half of the Retuning subframe shown in FIG. 14, since the Shortened PUCCH format is applied as it is, there is no need to define a new PUCCH format and it is not necessary to change the ACK / NACK signal mapping method.

  Thus, in the present embodiment, in the first half of the Retuning subframe, since symbols that are not used for ACK / NACK signal and DMRS mapping in Shortened PUCCH format are used for Retuning time, orthogonality between orthogonal code sequences is provided. There is no loss of sex. In the latter half of the Retuning subframe, the ACK / NACK signal is spread in the same manner as in the Shortened PUCCH format, and the signal is transmitted with a timing offset of 1 SC-FDMA symbol added. By this means, even if a symbol for Retuning is secured, the signal of the Shortened PUCCH format is maintained as it is, and therefore orthogonality between orthogonal code sequences does not collapse. Therefore, the orthogonality between orthogonal code sequences does not collapse in each Retuning subframe.

  Further, in the present embodiment, since there is no limitation on the use of the orthogonal code sequence (OCC sequence), the maximum value of the number of terminals that can be multiplexed by the orthogonal code sequence is 3 (that is, equation (2) Can be maintained at c = 3).

[Modification of Second Embodiment or Third Embodiment]
Embodiments 2 and 3 have described the case where a format in which the Shortened PUCCH format or the mapping of the Shortened PUCCH format is partially changed is used as the format for transmitting the ACK / NACK signal in the Retuning subframe. On the other hand, in the present modification, when frequency hopping is applied in uplink transmission, terminal 200 is not limited to the Retuning subframe, but in all subframes to which repetition is applied, Shortened PUCCH format or Shortened PUCCH repetition transmission is performed using a format in which the mapping of PUCCH format is partially changed.

  FIG. 15 shows a state of frequency hopping in PUCCH repetition when Y = 4.

  As shown in FIG. 15, when terminal 200 transmits the repetition signal in Y = 4 subframes in succession, terminal 200 changes the frequency band by frequency hopping and transmits the repetition signal in 4 consecutive subframes again. At this time, the Shortened PUCCH format is used in all 4 subframes before Retuning, and the format in which the mapping of the Shortened PUCCH format is partially changed is used in all 4 subframes after Retuning.

  By doing this, the ACK / NACK signal is multiplied by the same OCC sequence in the Retuning subframe and the other subframes, so that the base station 100 performs channel estimation of a plurality of subframes using the Y subframe and Symbol level synthesis can be performed. In other words, the Retuning subframe and other subframes are multiplied by different OCC sequences for the ACK / NACK signal (specifically, DFT sequences for Retuning subframes and Walsh sequences for other subframes). Therefore, it is possible to prevent the demodulation process from becoming complicated because the signal before despreading cannot be in-phase combined on the base station 100 side.

(Embodiment 4)
When the terminal transmits PUCCH and PUSCH in consecutive subframes, respectively, and the 1.4 MHz frequency band (narrow band) for PUCCH transmission and the 1.4 MHz frequency band (narrow band) for PUSCH transmission are different , Retuning is also required between PUCCH transmission and PUSCH transmission.

  Embodiments 1 to 3 have described Retuning in frequency hopping when PUSCH or PUCCH is transmitted by repetition. On the other hand, the present embodiment describes Retuning in PUCCH transmission after PUSCH transmission or PUSCH transmission after PUCCH transmission.

  The base station and terminal according to the present embodiment have the same basic configuration as base station 100 and terminal 200 according to Embodiment 1, and will be described with reference to FIGS. 9 and 10.

  In this embodiment, Method 1 (FIG. 4) and Method 2 (FIG. 5) are used among Methods 1 to 4 for securing the above-mentioned Retuning time. That is, the terminal 200 switches the narrow band to be used by frequency hopping, discards the trailing 2SC-FDMA data symbol of one subframe immediately before Retuning and sets it as Retuning time, or the first 2SC of one subframe immediately after Retuning. -The FDMA data symbol may be discarded and set as Retuning time.

  In addition, in the present embodiment, when PUSCH transmission and PUCCH transmission are performed in consecutive subframes, orthogonalization is performed by setting a Retuning subframe as in Embodiment 1 (for example, FIG. 11). Retuning for changing the 1.4 MHz frequency band transmitted by the terminal 200 may be ensured without causing the orthogonality of the code sequence to collapse.

In the present embodiment, base station 100 notifies terminal 200 of the number of repetitions of _PUSCH (N _PUSCH ) or the number of repetitions of _PUCCH (N _PUCCH ) in advance before transmission / reception of PUSCH or PUCCH. The repetition times N _PUSCH and N _PUCCH may be notified from the base station 100 to the terminal 200 via an upper layer specific to the terminal, or may be notified using the PDCCH for MTC.

Terminal 200 _{repeats PUSCH} or _PUCCH by the repetition count (N _PUSCH or N _PUCCH ) notified from base station 100.

  In addition, when terminal 200 performs PUCCH repetition transmission from the subframe subsequent to the subframe in which PUSCH repetition transmission has ended, terminal 200 has a 1.4 MHz frequency band for PUSCH transmission and a 1.4 MHz frequency band for PUCCH transmission. 16 is different, puncturing the last 2SC-FDMA symbol of the PUSCH subframe immediately before Retuning is ensured as Retuning time according to Method 1 (see FIG. 4).

  On the other hand, when terminal 200 performs PUSCH repetition transmission from the subframe subsequent to the subframe in which PUCCH repetition transmission is completed, terminal 200 has a 1.4 MHz frequency band for PUSCH transmission and a 1.4 MHz frequency band for PUCCH transmission. 17, the first 2SC-FDMA symbol of the PUSCH subframe immediately after Retuning is punctured and secured as Retuning time according to Method 2 (see FIG. 5), as shown in FIG.

  That is, when Retuning is required immediately before PUCCH repetition transmission, terminal 200 discards the trailing 2SC-FDMA symbol of one subframe immediately before PUCCH repetition starts and sets it as Retuning time. Also, when Retuning is required immediately after PUCCH repetition transmission, terminal 200 discards the first 2SC-FDMA symbols of one subframe immediately after PUCCH repetition ends and sets it as Retuning time.

  In other words, when PUSCH repetition transmission and PUCCH repetition transmission are performed in consecutive subframes and PUSCH transmission and PUCCH transmission have different 1.4 MHz frequency bands, terminal 200 transmits PUSCH. Puncture the 2SC-FDMA symbol immediately before (FIG. 16) or immediately after (1.4) the 1.4 MHz frequency band (narrow band) in the subframe is switched to secure the retuning time.

  In this way, when PUSCH transmission and PUCCH transmission are continuous, the following problem can be solved by setting the Retuning subframe on the PUSCH side.

  First, Retuning from PUSCH transmission to PUCCH transmission shown in FIG. 16 will be described.

  At this time, the base station 100 transmits an uplink grant instructing the terminal 200 to allocate the PUSCH via the downlink control channel for MTC, before the PUSCH is transmitted / received.

  The terminal 200 can transmit the PUSCH when the uplink grant can be correctly decoded. In this case, when PUCCH transmission is performed in consecutive subframes after PUSCH transmission, terminal 200 performs Retuning and starts PUCCH transmission, and thus requires Retuning time between PUSCH transmission and PUCCH transmission. .

  On the other hand, the terminal 200 does not transmit the PUSCH when the uplink grant cannot be correctly decoded. In this case, since PUSCH transmission immediately before PUCCH transmission is not performed, terminal 200 does not need to perform Retuning immediately before PUCCH transmission. In such a case, if the Retuning subframe is set on the PUCCH side, the base station 100 assumes that the first subframe of the PUCCH repetition is the Retuning subframe, whereas the terminal 200 actually sets the first subframe of the PUCCH repetition in the same manner as a normal subframe and transmits an ACK / NACK signal. Therefore, in the first subframe of the PUCCH repetition, a mismatch occurs between the PUCCH assumed by the base station 100 and the PUCCH actually transmitted by the terminal 200.

  On the other hand, in the present embodiment, when PUCCH transmission is performed in consecutive subframes after PUSCH transmission, the Retuning subframe is set only on the PUSCH side. By doing so, the head subframe of PUCCH repetition can always be used as a normal subframe, without depending on the success or failure of decoding of the uplink grant. Therefore, there is no mismatch in PUCCH between base station 100 and terminal 200. Also, since the Retuning subframe is set only on the PUSCH side, the setting of Retuning time does not affect the orthogonality of OCC sequences on PUCCH.

  Next, Retuning from PUCCH transmission to PUSCH transmission shown in FIG. 17 will be described.

  Retuning from PUCCH transmission to PUSCH transmission can be considered in the same way as Retuning from PUSCH transmission to PUCCH transmission. That is, the base station 100 transmits the uplink grant instructing the terminal 200 to allocate the PUSCH via the downlink control channel for MTC, before the PUSCH is transmitted / received.

  The terminal 200 can transmit the PUSCH when the uplink grant can be correctly decoded. In this case, when PUSCH transmission is performed in consecutive subframes after PUCCH transmission, terminal 200 performs Retuning and starts PUSCH transmission, and thus requires Retuning time between PUCCH transmission and PUSCH transmission. .

  On the other hand, the terminal 200 does not transmit the PUSCH when the uplink grant cannot be correctly decoded. In this case, since PUSCH transmission immediately after PUCCH transmission is not performed, terminal 200 does not need to perform Retuning immediately after PUCCH transmission. In such a case, if the Retuning subframe is set on the PUCCH side, the base station 100 assumes that the last subframe of the PUCCH repetition is the Retuning subframe. Terminal 200 actually sets the subframe at the end of the PUCCH repetition in the same manner as a normal subframe and transmits an ACK / NACK signal. For this reason, in the subframe at the end of the PUCCH repetition, a mismatch occurs between the PUCCH assumed by the base station 100 and the PUCCH actually transmitted by the terminal 200.

  On the other hand, in the present embodiment, when PUSCH transmission is performed in consecutive subframes after PUCCH transmission, the Retuning subframe is set only on the PUSCH side. By doing so, the rear subframe of PUCCH repetition can always be used as a normal subframe without depending on the success or failure of decoding of the uplink grant. Therefore, there is no mismatch in PUCCH between base station 100 and terminal 200. Moreover, since the Retuning subframe is set only on the PUSCH side, the setting of the Retuning time does not affect the orthogonality of OCC of PUCCH.

(Embodiment 5)
The base station and terminal according to the present embodiment have the same basic configuration as base station 100 and terminal 200 according to Embodiment 1, and will be described with reference to FIGS. 9 and 10.

  In the method of securing the retuning time based on any of the methods 1 to 3 described in the first to fourth embodiments, resources in the terminal 200 are compared with method 4 in which a guard subframe (1 subframe) is provided for retuning. Use efficiency can be improved. When the frequency hopping period is Y subframes, the resource utilization efficiency of Method 4 is (Y-1) / Y. On the other hand, the resource utilization efficiency of Methods 1 to 3 is (Y-1 + (12/14)) / Y. For example, when Y = 4, methods 1 to 3 can improve resource utilization efficiency by 28% as compared with method 4.

  On the other hand, in the case of PUCCH, a plurality of terminals 200 can be multiplexed within the same time / frequency resource by the orthogonal code sequence (OCC sequence). Therefore, in addition to the resource utilization efficiency in the terminal 200, the resource utilization efficiency in the network is also an important index.

  The resource utilization efficiency of PUCCH in the network is obtained by multiplying the resource utilization efficiency of terminal 200 by the number of terminals that can be multiplexed by the orthogonal code sequence (for example, c in equation (2)). That is, the PUCCH resource utilization efficiency in the network is 2 * (Y-1 + (12/14)) / Y in the first and fourth embodiments (method 1 or method 2. c = 2). In 2 and 3 (method 3, c = 3), 3 * (Y-1 + (12/14)) / Y is obtained. On the other hand, method 4, that is, the PUCCH resource utilization efficiency in the network when the guard subframe (1 subframe) is provided for Retuning is 3 * (Y-1) / Y.

  From the above, it can be said that the PUCCH resource utilization efficiency in the network is highest in the second and third embodiments. On the other hand, in the first or fourth embodiment, the number of terminals that can be multiplexed by OCC is limited to 3 to 2, so that the resource utilization efficiency of PUCCH in the network decreases.

  Specifically, as described above, the resource utilization efficiency of PUCCH in the network of the method of Embodiment 1 is 2 * (Y-1 + (12/14)) / Y, and method 4 (for Retuning) The resource utilization efficiency of PUCCH in the network of the method of providing a guard subframe) is 3 * (Y-1) / Y. Therefore, comparing the resource utilization efficiencies of both, when Y> 2.72, that is, when the frequency hopping period Y is 3 or more, the method 4 has a PUCCH resource utilization efficiency in the network more than the method of the first embodiment. Grows larger.

  Therefore, in the present embodiment, a case will be described in which the method of Embodiment 1 and method 4 (method of providing a guard subframe for Retuning) are used in combination in consideration of PUCCH resource utilization efficiency in the network. . Specifically, terminal 200 switches between the method of Embodiment 1 and method 4 (a method of providing a guard subframe for Retuning) according to the frequency hopping cycle.

  FIG. 18 shows a state of frequency hopping in PUCCH repetition when Y = 2 (<3), and FIG. 19 shows a state of frequency hopping in PUCCH repetition when Y = 4 (≧ 3).

  As shown in FIG. 18, when the frequency hopping period is less than 3, terminal 200 performs the method of Embodiment 1, that is, punctures the tail 2SC-FDMA symbol of the subframe immediately before Retuning and sets Retuning time. Secure. On the other hand, as shown in FIG. 19, when the frequency hopping period is 3 or more, the terminal 200 does not perform puncturing of the 2SC-FDMA symbols, and the method 4, that is, the guard sub between the subframes before and after Retuning. Provide a frame to secure Retuning time.

  In this way, the terminal 200 can optimize the resource utilization efficiency of PUCCH in the network by switching the method for securing the Retuning time according to the frequency hopping cycle. Further, in method 4, since the entire subframe is discarded in the Retuning subframe, the orthogonality of PUCCH does not collapse.

  However, the method is not limited to the case where terminal 200 determines which method (method of Embodiment 1 or method 4) to use based on the frequency hopping cycle. For example, the base station 100 may notify the terminal 200 of which method (the method of the first embodiment or the method 4) to be used via the cell-specific upper layer, and the terminal 200 is notified to the terminal 200. It may be notified via a unique upper layer.

  Further, the operation of determining which method (the method of the first embodiment or the method 4) the terminal 200 uses may be an operation that is determined to be predefined in the standard. For example, when terminal 200 is in coverage expansion mode A (No / small repetition) (that is, when the number of repeated subframes is short), the frequency hopping cycle is also assumed to be short, and therefore the first embodiment When the terminal 200 is in the coverage extension mode B (Large repetition) (that is, the number of subframes to be repeated is long), it is assumed that the frequency hopping cycle is long. Can also be used.

Further, the threshold value Y _th for switching the method for ensuring the Retuning time may be used as a parameter. Y _th may be reported as a cell-specific parameter to the terminal 200 by the base station 100 via a cell-specific upper layer, and as a terminal-specific parameter, the base station 100 may be terminal-specific to the terminal 200. May be notified via the upper layer of. In addition, Y _th may be a parameter that is defined as predefined in the standard.

(Embodiment 6)
PUCCH not only transmits ACK / NACK signals, but also transmits CSI feedback that is periodically transmitted in the uplink. When CSI feedback transmission or CSI feedback transmission and ACK / NACK signal transmission overlap, PUCCH format 2 / 2a / 2b is used. FIG. 20 shows a subframe configuration example of PUCCH format 2 / 2a / 2b. As shown in FIG. 20, two DMRSs and five SC-FDMA data symbols (CSI feedback information) are time-multiplexed in each slot.

  Therefore, in the present embodiment, the operation of Retuning for PUCCH format 2 / 2a / 2b will be described.

  Note that repetition transmission of PUCCH format 2 / 2a / 2b is not assumed. In the following, as an example, the operation in the case where repetition transmission using PUCCH format 1 / 1a / 1b or repetition transmission of PUSCH and transmission using PUCCH format 2 / 2a / 2b occur in consecutive subframes. explain.

  When the subframe using PUCCH format 2 / 2a / 2b is a Retuning subframe, as in Method 1 (FIG. 4) or Method 2 (FIG. 5), the end of one subframe immediately before Retuning or immediately after Retuning When the leading 2SC-FDMA symbol of one subframe is punctured, DMRS is punctured. In this case, the base station 100 cannot use DMRS, which makes demodulation difficult.

  Therefore, in the present embodiment, terminal 200 drops one subframe of one of the channels before and after Retuning, when Retuning is required before and after transmission using PUCCH format 2 / 2a / 2b.

  Which channel is prioritized (or dropped) before and after Retuning depends on the priority standard. For example, in the current standard, the priority is generally in the order of ACK / NACK signal> PUSCH> periodic CSI. In this case, PUCCH format 2 / 2a / 2b immediately before or immediately after Retuning has a low priority and is therefore dropped.

  In this way, by dropping either one of the channels according to the priority, it is possible to prevent the influence on the channel with high priority in Retuning. For example, when the priority of the ACK / NACK signal is increased, the influence on the PUCCH format 1 / 1a / 1b due to the drop can be prevented, so that the orthogonality of the PUCCH is not broken. On the contrary, even when the priority of the ACK / NACK signal is lowered, the entire subframe of the ACK / NACK signal is discarded, so that the orthogonality of PUCCH is not affected.

  Note that method 3 (FIG. 6) may be applied when Retuning is required before and after transmission using PUCCH format 2 / 2a / 2b. That is, terminal 200 may puncture the last 1 symbol of one subframe immediately before Retuning and the first 1 symbol of one subframe immediately after Retuning. In this case, DMRS is not punctured even if the subframe using PUCCH format 2 / 2a / 2b becomes the Retuning subframe. Therefore, the puncture does not affect the demodulation in the base station 100.

  The embodiments of the present disclosure have been described above.

  Note that, although cases have been described with the above embodiment as examples where an aspect of the present disclosure is configured by hardware, the present disclosure can also be implemented by software in cooperation with hardware.

  Further, each functional block used in the description of the above embodiments is typically realized as an LSI which is an integrated circuit. The integrated circuit may control each functional block used in the description of the above embodiment, and may have an input and an output. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  The method of circuit integration is not limited to LSI, and it may be realized by a dedicated circuit or a general-purpose processor. A field programmable gate array (FPGA) that can be programmed after the LSI is manufactured, or a reconfigurable processor capable of reconfiguring the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. The application of biotechnology is possible.

  A terminal according to the present disclosure spreads an ACK / NACK signal for downlink data over a plurality of subframes by using a spreading unit that spreads an ACK / NACK signal for downlink data using any one of a plurality of orthogonal code sequences. A repetition section that repeats, a signal allocation section that maps the repeated ACK / NACK signal to a narrow band for MTC terminals, and a narrow band used in the first sub-frame among a plurality of sub-frames, When the narrow band used in the second sub-frame continuous to the first sub-frame is different, the control unit puncturing the last two symbols of the first sub-frame or the first two symbols of the second sub-frame, and the narrow band A transmission unit for transmitting an ACK / NACK signal, wherein each of the plurality of orthogonal code sequences includes a first partial sequence including a code corresponding to the first two symbols of the subframe. It is composed of a second partial series consisting of codes corresponding to the two symbols of the tail, the first partial series and the second partial series are respectively partially orthogonal among a plurality of orthogonal code sequences.

  The terminal of the present disclosure, a spreading unit that spreads an ACK / NACK signal for downlink data, a repetition unit that repeats the spread ACK / NACK signal over a plurality of subframes, and a repeated ACK / NACK signal. A signal allocation unit that maps a signal to a narrow band for MTC terminals, a narrow band used in a first subframe of a plurality of subframes, and a narrow band used in a second subframe that is continuous with the first subframe. When the bands are different, a control unit that punctures one symbol at the tail of the first subframe and one symbol at the beginning of the second subframe, and a transmission unit that transmits an ACK / NACK signal in a narrow band are provided. Then, the spreading unit spreads the ACK / NACK signal mapped to the first subframe and the second subframe using the Shortened PUCCH format, and the transmitting unit spreads to the first subframe. The mappings ACK / NACK signal transmitted according Shortened PUCCH format, and transmits the ACK / NACK signal symbol other than the first one symbol to the second sub-frame.

  In the terminal of the present disclosure, the control unit further includes a narrow band used in the third subframe in which the ACK / NACK signal is transmitted and a fourth subframe in which the uplink data is transmitted, which is continuous with the third subframe. When the narrow band used is different, the two symbols immediately before or after the narrow band in the fourth subframe is switched are punctured.

  In the terminal of the present disclosure, the control unit performs a frequency hopping cycle by hopping a narrow band used in each of a plurality of subframes or a puncturing of two symbols when the length of the plurality of subframes is less than a threshold. Alternatively, a guard subframe is provided between the first subframe and the second subframe without performing puncturing of two symbols when the lengths of the plurality of subframes are equal to or greater than the threshold value.

  In the terminal according to the present disclosure, the signal allocation unit maps the spread ACK / NACK signal in the second subframe to symbols other than the first one symbol and the symbol to which the reference signal is mapped.

  In the terminal of the present disclosure, the signal allocation unit maps the spread ACK / NACK signal in the second subframe according to the Shortened PUCCH format, and the transmission unit has a timing of one symbol at the transmission timing of the second subframe. Add an offset.

  The transmission method of the present disclosure spreads an ACK / NACK signal for downlink data using any one of a plurality of orthogonal code sequences, and repeats the spread ACK / NACK signal over a plurality of subframes. The ACK / NACK signal subjected to the repetition and repetition to the narrow band for the MTC terminal, and the narrow band used in the first sub-frame and the second sub-frame that is continuous in the first sub-frame among the plurality of sub-frames. If the narrow band used in the frame is different, the last two symbols of the first subframe or the first two symbols of the second subframe are punctured, ACK / NACK signals are transmitted in the narrow band, and a plurality of orthogonal code sequences are transmitted. Each of the first sub-sequences is composed of a first partial sequence consisting of codes corresponding to the first two symbols of the subframe and a second partial sequence consisting of codes corresponding to the last two symbols of the sub-frame. Min sequence and second partial series are respectively partially orthogonal among a plurality of orthogonal code sequences.

  The transmission method of the present disclosure spreads ACK / NACK signals for downlink data, repeats spread ACK / NACK signals over a plurality of subframes, and repeats ACK / NACK signals for MTC terminals. If the narrow band used in the first sub-frame and the narrow band used in the second sub-frame consecutive to the first sub-frame are different from each other in the plurality of sub-frames by mapping to the narrow band, The ACK / NACK signal that is mapped to the first subframe and the second subframe by puncturing the last 1 symbol and the first 1 symbol of the second subframe and transmitting the ACK / NACK signal in a narrow band is The ACK / NACK signal spread using the Shortened PUCCH format and mapped to the first subframe is transmitted according to the Shortened PUCCH format, and mapped to the second subframe. The ACK / NACK signal is transmitted in symbols other than the beginning of one symbol.

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

100 base station 200 terminal 101,209 control unit 102 control signal generation unit 103 control signal coding unit 104 control signal modulation unit 105,210 data coding unit 106 retransmission control unit 107 data modulation unit 108,217 signal allocation unit 109,218 IFFT section 110, 219 CP addition section 111, 220 Transmission section 112, 201 Antenna 113, 202 Reception section 114, 203 CP removal section 115, 204 FFT section 116, 205 Extraction section 117 Demapping section 118 Channel estimation section 119 Equalization section 120 demodulation section 121 decoding section 122, 125 determination section 123 despreading section 124 correlation processing section 206 data demodulation section 207 data decoding section 208 CRC section 211 CSI signal generation section 212 response signal generation section 213 modulation section 214 DFT section 215 spreading section 216 Repetition department

Claims (21)

A first narrow band used in a first sub-frame for receiving a first channel and a second narrow band used in a second sub-frame that is continuous with the first sub-frame and receives a second channel If is different from, a control unit that punctures 2 symbols and sets as Retuning time,
A receiver for receiving the first channel and the second channel,
The control unit is
When the first channel and the second channel are PUSCH (Physical Uplink Shared CHannel), the last one symbol of the first subframe and the first one symbol of the second subframe are punctured. ,
If the first channel is the PUSCH and the second channel is the PUCCH (Physical Uplink Control CHannel), puncture the last two symbols of the first subframe,
base station. The control unit punctures the first two symbols of the second subframe when the first channel is the PUCCH and the second channel is the PUSCH.
The base station according to claim 1. When the first channel and the second channel are the PUCCH and an ACK / NACK signal is received on the PUCCH, in the first subframe, a sequence having the same sequence length of 4 in the first half slot and a sequence in the second half slot are used. A sequence having a sequence length of 3 is used, and in the second subframe, a sequence having a sequence length of 3 is used in the first half slot and a sequence having a sequence length of 4 is used in the second half slot.
The base station according to claim 1. The control unit, when the first channel and the second channel are the PUCCH, and when receiving a CSI (Channel State information) signal on the PUCCH, with the last 1 symbol of the first subframe, Puncture the first 1 symbol of the second subframe,
The base station according to claim 1. The control unit switches from the first narrow band to the second narrow band by frequency hopping.
The base station according to claim 1. The first narrow band and the second narrow band are set for MTC (Machine Type Communication) terminals,
The base station according to claim 1. When the PUCCH is used as the first channel and the second channel and PUCCH Format 2 is used in the PUCCH, the control unit controls the last 1 symbol of the first subframe and the second subframe. Puncture the first 1 symbol of a subframe,
The base station according to claim 1. A first narrow band used in a first sub-frame for receiving a first channel and a second narrow band used in a second sub-frame that is continuous with the first sub-frame and receives a second channel If is different, puncture 2 symbols and set as Retuning time,
Receiving the first channel and the second channel,
When the first channel and the second channel are PUSCH (Physical Uplink Shared CHannel), the last 1 symbol of the first subframe and the first 1 symbol of the second subframe are punctured. ,
If the first channel is the PUSCH and the second channel is the PUCCH (Physical Uplink Control CHannel), puncture the last two symbols of the first subframe,
Receiving method. Puncturing the first two symbols of the second subframe when the first channel is the PUCCH and the second channel is the PUSCH;
The receiving method according to claim 8. When the first channel and the second channel are the PUCCH and an ACK / NACK signal is received on the PUCCH, in the first subframe, a sequence with the same sequence length of 4 in the first half slot and a sequence in the second half slot are used. A sequence with a sequence length of 3 is used, and in the second subframe, a sequence with a sequence length of 3 is used in the first half slot, and a sequence with a sequence length of 4 is used in the latter half slot.
The receiving method according to claim 8. When the first channel and the second channel are the PUCCH and a CSI (Channel State information) signal is received on the PUCCH, the last one symbol of the first subframe and the second subframe Puncture the first 1 symbol of the frame,
The receiving method according to claim 8. Switching from the first narrowband to the second narrowband by frequency hopping,
The receiving method according to claim 8. The first narrow band and the second narrow band are set for MTC (Machine Type Communication) terminals,
The receiving method according to claim 8. When the first channel and the second channel are the PUCCH and PUCCH Format 2 is used in the PUCCH, the last one symbol of the first subframe and the first symbol of the second subframe are used. Puncture one symbol,
The receiving method according to claim 8. A first narrow band used in a first sub-frame for receiving a first channel and a second narrow band used in a second sub-frame that is continuous with the first sub-frame and receives a second channel If and are different, the process of puncturing 2 symbols and setting as Retuning time,
Controlling the process of receiving the first channel and the second channel,
When the first channel and the second channel are PUSCH (Physical Uplink Shared CHannel), the last 1 symbol of the first subframe and the first 1 symbol of the second subframe are punctured. ,
If the first channel is the PUSCH and the second channel is the PUCCH (Physical Uplink Control CHannel), puncture the last two symbols of the first subframe,
Integrated circuit. Puncturing the first two symbols of the second subframe when the first channel is the PUCCH and the second channel is the PUSCH;
The integrated circuit according to claim 15. When the first channel and the second channel are the PUCCH and an ACK / NACK signal is received on the PUCCH, in the first subframe, a sequence with the same sequence length of 4 in the first half slot and a sequence in the second half slot are used. A sequence with a sequence length of 3 is used, and in the second subframe, a sequence with a sequence length of 3 is used in the first half slot, and a sequence with a sequence length of 4 is used in the latter half slot.
The integrated circuit according to claim 15. When the first channel and the second channel are the PUCCH and a CSI (Channel State information) signal is received on the PUCCH, the last one symbol of the first subframe and the second subframe Puncture the first 1 symbol of the frame,
The integrated circuit according to claim 15. Switching from the first narrowband to the second narrowband by frequency hopping,
The integrated circuit according to claim 15. The first narrow band and the second narrow band are set for MTC (Machine Type Communication) terminals,
An integrated circuit according to any one of claims 15 to 19. When the first channel and the second channel are the PUCCH and PUCCH Format 2 is used in the PUCCH, the last one symbol of the first subframe and the first symbol of the second subframe are used. Puncture one symbol,
The integrated circuit according to claim 15.

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