JP2014096805A - Mobile terminal device, radio communication method and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently transmit feedback control information on a physical uplink control channel.SOLUTION: A mobile terminal device comprises: an ACK/NACK signal encoding unit that generates multiple-bit ACK/NACK information by jointly encoding ACK/NACK information in response to a downlink shared data channel signal among multiple basic frequency blocks; a channel encoding unit that channel encodes the multiple-bit ACK/NACK information; a DFT unit that applies DFT to the channel encoded signal; and a block spreading unit that applies block spreading to the signal after DFT by block spreading codes. The block spreading unit applies a condensed format if the multiple-bit ACK/NACK information is transmitted in a sub-frame in which symbols to transmit a sounding reference signal (SRS) for channel quality measurement are multiplexed in time, and applies a normal format if transmitted in a sub-frame not including symbols to transmit the SRS.

Description

  The present invention relates to a mobile terminal apparatus, a radio communication method, and a radio communication system in a next generation mobile communication system.

  In a UMTS (Universal Mobile Telecommunications System) network, HSDPA (High Speed Downlink Packet Access) or HSUPA (High Speed Uplink Packet Access) is adopted for the purpose of improving frequency utilization efficiency and peak data rate. A system based on CDMA (Wideband Code Division Multiple Access) is maximally extracted. For this UMTS network, Long Term Evolution (LTE) has been studied for the purpose of further improving frequency utilization efficiency and peak data rate, and reducing delay (Non-Patent Document 1). In LTE, unlike W-CDMA, as a multi-access method, a method based on OFDMA (Orthogonal Frequency Division Multiple Access) is used for the downlink (downlink), and SC-FDMA (Single Carrier) is used for the uplink (uplink). A method based on Frequency Division Multiple Access) is used.

  As shown in FIG. 1, a signal transmitted in the uplink is mapped to an appropriate radio resource and transmitted from the mobile terminal apparatus to the radio base station apparatus. In this case, user data (UE (User Equipment) # 1, UE # 2) is allocated to an uplink shared channel (PUSCH: Physical Uplink Shared Channel), and when control information is transmitted simultaneously with user data, PUSCH and When time-multiplexed and only control information is transmitted, it is assigned to an uplink control channel (PUCCH: Physical Uplink Control Channel). The control information transmitted on the uplink includes downlink quality information (CQI: Channel Quality Indicator), a downlink shared channel retransmission response (ACK / NACK), and the like.

  PUCCH typically employs different subframe configurations when transmitting CQI and ACK / NACK (FIGS. 2A and 2B). The PUCCH subframe configuration includes seven SC-FDMA symbols in one slot (1/2 subframe). Further, one SC-FDMA symbol includes 12 information symbols (subcarriers). Specifically, as shown in FIG. 2 (a), the CQI subframe configuration (CQI format) includes a reference signal (RS :) for the second symbol (# 2) and the sixth symbol (# 6) in the slot. Reference Signal) is multiplexed, and control information (CQI) is multiplexed to other symbols (first symbol, third symbol to fifth symbol, seventh symbol). In addition, as shown in FIG. 2B, the ACK / NACK subframe configuration (ACK / NACK format) includes reference signals (RS) in the third symbol (# 3) to the fifth symbol (# 5) in the slot. : Reference Signal) is multiplexed, and control information (ACK /) is transferred to other symbols (first symbol (# 1), second symbol (# 2), sixth symbol (# 6), and seventh symbol (# 7)). NACK) is multiplexed. In one subframe, the slot is repeated twice. Also, as shown in FIG. 1, the PUCCH is multiplexed on radio resources at both ends of the system band, and frequency hopping (Inter-slot FH) is applied between two slots having different frequency bands in one subframe. The PUSCH subframe configuration includes seven SC-FDMA symbols in one slot.

3GPP, TR25.912 (V7.1.0), "Feasibility study for Evolved UTRA and UTRAN", Sept. 2006

  The third generation system (W-CMDA) can generally achieve a transmission rate of about 2 Mbps at the maximum on the downlink using a fixed band of 5 MHz. On the other hand, in the LTE system, a transmission rate of about 300 Mbps at the maximum in the downlink and about 75 Mbps in the uplink can be realized using a variable band of 1.4 MHz to 20 MHz. In addition, in the UMTS network, a successor system of LTE is also studied for the purpose of further improving the frequency utilization efficiency and the peak data rate (for example, LTE advanced or LTE enhancement (hereinafter referred to as “the LTE advanced”). LTE-A ")).

  In the LTE-A system, with the goal of further improving the frequency utilization efficiency, peak throughput, and the like, allocation of frequencies wider than LTE is being studied. In LTE-A (for example, Rel. 10), one requirement is to have backward compatibility with LTE. For this reason, a basic frequency block having a bandwidth that can be used by LTE. A transmission band configuration in which a plurality of (component carriers) (CC) are arranged is employed. For this reason, the feedback control information for the data channel transmitted by a plurality of downlink CCs simply increases to the number of CCs. For this reason, since the amount of feedback control information increases, it is necessary to study a method for transmitting feedback control information in an uplink channel.

  The present invention has been made in view of such points, and an object thereof is to provide a mobile terminal device, a radio communication method, and a radio communication system that can efficiently transmit feedback control information through a physical uplink control channel. .

  The mobile terminal apparatus of the present invention includes an ACK / NACK signal encoder that jointly encodes ACK / NACK information for a downlink shared data channel signal between a plurality of basic frequency blocks to generate a plurality of bits of ACK / NACK information, A channel coding unit that channel-codes multi-bit ACK / NACK information, a DFT unit that performs DFT (Discrete Fourier Transform) on the channel-coded signal, and a block that performs block spreading on the signal after DFT with a block spreading code A spreader, wherein the block spreader is a subframe in which the multi-bit ACK / NACK information is time-multiplexed with symbols for transmitting channel quality measurement SRS (Sounding Reference Signal). 1 of symbols for ACK / NACK information in subframe when transmitted When the abbreviated format is deleted and the ACK / NACK information of multiple bits is transmitted in a subframe that does not include a symbol for transmitting the SRS, the normal format in which the number of symbols is not deleted It is characterized by applying.

  According to this configuration, it is possible to efficiently transmit feedback control information through the physical uplink control channel.

  According to the present invention, it is possible to efficiently transmit feedback control information through a physical uplink control channel.

It is a figure for demonstrating the channel structure which maps the signal of an uplink. It is a figure which shows a physical uplink control channel format. It is a figure which shows the encoding table which defined the encoding data of ACK / NACK / DTX according to the number of codewords. (A) It is a figure for demonstrating orthogonal multiplexing by CS (cyclic shift) base using a CAZAC code sequence, (b) It is a figure for demonstrating orthogonal multiplexing by OCC (orthogonal cover code) base. It is a figure for demonstrating the orthogonality between users in case SRS is multiplexed in the code multiplexing of CS (cyclic shift) base. It is a figure for demonstrating the orthogonality between users in case SRS is multiplexed in the code multiplexing of an OCC (orthogonal cover code) base. (A) It is a conceptual diagram of the method of time-multiplexing simultaneously in PUSCH, (b) It is a conceptual diagram of the method of transmitting PUCCH and PUSCH simultaneously. It is a figure which shows schematic structure of the mobile terminal device which concerns on Embodiment 1 of this invention. It is a figure which shows schematic structure of the radio base station apparatus which concerns on Embodiment 1, 2 of this invention. It is a figure which shows schematic structure of the mobile terminal apparatus which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[PDCCH not detected (DTX) notification method]
In LTE (Rel. 8), in the notification of ACK / NACK (Format 1a / 1b) for the downlink data channel (PDSCH), the following multiple states can be notified.

  In the case of 1 codeword transmission, there are three states of ACK, NACK, and DTX. State.

  Here, DTX is a state in which no response is transmitted on the uplink (PDCCH undetected state) because the user terminal UE has not received the PDCCH. The base station can determine that it is DTX when the received power in the resource allocated to ACK / NACK in the uplink is equal to or less than a predetermined value.

  The code word indicates a coding unit of channel coding (error correction coding), and one or a plurality of code words are transmitted when MIMO multiple transmission is applied. In LTE, a maximum of 2 codewords are used in single user MIMO. In the case of two-layer transmission, each layer is an independent codeword, and in the case of four-layer transmission, one codeword is provided for every two layers.

  When transmitting PDSCH using multiple CCs, if the user terminal UE tries to be able to notify the above-described 3 states (1 codeword) or 5 states (2 codewords) for each CC, the maximum number of encoded bits is There is a growing problem.

  In one aspect of the present invention, ACK / NACK information for a downlink data channel is jointly encoded between a plurality of CCs to generate a multi-bit ACK / NACK information, and the multi-bit ACK / NACK information is transmitted in the uplink. In this case, the ACK / NACK information is notified by encoding the ACK / NACK information so that the DTX information bits are not transmitted independently depending on conditions, and reducing the maximum number of encoded bits.

(1) DTX notification is turned ON / OFF corresponding to the number of code words.
In the case of 1 codeword transmission, information bits are individually assigned and notified for 3 states (ACK, NACK, DTX) per CC, but in the case of 2 codeword transmission, information bits are not assigned to DTX independently. Thus, notification is performed by individually allocating information bits with respect to four states (ACK / ACK, ACK / NACK, NACK / ACK, NACK / NACK, or DTX) per CC. That is, DTX is encoded and notified only for one codeword, but is not notified for two codewords.

  FIG. 3 is a configuration example of a coding table applied to the DTX (PDCCH not detected) notification method of the present invention.

  In the case of 1 codeword transmission, 3 states (ACK, NACK, DTX) are defined per CC, and information bits of “00” are assigned to DTX, “01” is assigned to NACK, and “10” is assigned to ACK. ing.

  In the case of 2-codeword transmission, 4 states (ACK / ACK, ACK / NACK, NACK / ACK, NACK / NACK or DTX) are defined per CC, and NACK / NACK or DTX is “00”, NACK / ACK. Is assigned information bits of “01”, ACK / NACK is “10”, and ACK / ACK is “11”. That is, in the case of two codewords, one information bit (00) is assigned to the DTX or NACK / NACK state, and the number of states is reduced. Encoding is performed so that information bits are not notified by DTX alone. The base station repeats retransmission until ACK is notified on the uplink.

  As a result, the number of states to be notified is reduced to four states when transmitting two codewords, so that the maximum number of encoded bits can be reduced. For example, when the number of CCs = 5 and the number of states to be notified = 4, the maximum number of encoded bits is 10 bits. As in the conventional method, when the number of CCs is 5 and the number of states to be notified is 5, the maximum number of encoded bits is 12 bits, so 2 bits can be reduced.

(2) DTX notification is turned ON / OFF corresponding to the number of CCs.
When the number of CCs is less than or equal to X, 5 states (information bits are individually assigned to DTX) are encoded so that they can be notified when transmitting 2 codewords. When the number of CCs is greater than X, 4 states are transmitted when transmitting 2 codewords. The state (NACK / NACK or DTX common information bits are allocated) is encoded so as to be notified. That is, only when the number of CCs is less than or equal to X, DTX is independently encoded and notified in the uplink.

  For example, when the number of CCs is 4 or less, 3 states are notified when 1 codeword is transmitted, and 5 states are notified when 2 codewords are transmitted. When the number of CCs = 4 and the number of states to be notified = 4, the maximum number of encoded bits is 10 bits. When the number of CCs is larger than 4, 3 states are notified when 1 codeword is transmitted, and 4 states are notified when 2 codewords are transmitted. When the number of CCs = 5 and the number of states to be notified = 4, the maximum number of encoded bits is 10 bits.

  Thus, by turning ON / OFF the notification of DTX alone depending on the conditions, it is possible to reduce the maximum number of encoded bits when encoding and transmitting ACK / NACK information.

  As described above, the ACK / NACK information in which the number of states is conditionally reduced for each CC is encoded into a plurality of bits of ACK / NACK information by collectively encoding a plurality of CCs for each user. Uplink control information (ACK / NACK information, CQI information, reference signal (RS)) transmitted from each user terminal UE in the uplink is multiplexed between users.

[Abbreviated format configuration considering simultaneous transmission with SRS]
Here, a physical uplink control channel (PUCCH) format using orthogonal multiplexing will be described. When multiplexing uplink control channel signals of a plurality of users on the PUCCH, the uplink control channel signals are orthogonalized so that the uplink control channel signals can be separated for each user in the radio base station apparatus. Examples of such an orthogonal multiplexing method include an orthogonal multiplexing method using a cyclic shift of a CAZAC (Constant Amplitude Zero Auto Correlation) code sequence and an orthogonal multiplexing method using block spreading.

An orthogonal multiplexing method using a cyclic shift of a CAZAC code sequence is a sequence CAZAC # 1 (Δp) obtained by cyclically shifting a CAZAC code sequence having a code length L by Δp, and a sequence obtained by cyclically shifting the CAZAC code sequence by Δq. CAZAC # 1 (Δq) is an orthogonal multiplexing method utilizing orthogonality to each other. Therefore, in this method, the entire SC-FDMA symbol is mapped (block modulated) with control information on the SC-FDMA symbol to which the CAZAC code sequence having a different cyclic shift amount is mapped. Signals can be orthogonally multiplexed for each user. For example, as shown in FIG. 4A, a CAZAC code sequence having a specific cyclic shift amount (Δp) in a subframe configuration (format 2 / 2a / 2b) for transmitting ACK / NACK information is assigned to each SC. -Map to FDMA symbols. Then, block modulation is performed by the uplink control signals (ACK / NACK signal series) p _{1 to} p ₅ after data modulation. By assigning different cyclic shift amounts for each user, it is possible to orthogonalize uplink control channel signals between users. Thereby, in the radio base station apparatus, it is possible to separate the uplink control channel signal for each user. Note that the cyclic shift interval of the CAZAC code sequence assigned to the user is preferably set longer than the maximum delay amount of multipath.

Block spreading is an orthogonal multiplexing method that applies an orthogonal code (OCC) in the time direction. For example, as shown in FIG. 4B, a signal (ACK / NACK signal sequence) A in 1SC-FDMA is duplicated, and five SC-FDMA symbols (first symbol, third symbol to fifth symbol, first symbol) are copied. 7 symbols). Further, the spread codes Wp _{1 to} Wp ₅ are multiplied by the entire SC-FDMA symbol (first symbol, second symbol to fifth symbol, seventh symbol). By using spreading codes (orthogonal codes) that are orthogonal between different users, the uplink control channel signal can be orthogonalized between users, and the uplink control channel signal for each user can be separated in the radio base station apparatus. .

  Another aspect of the present invention is to jointly encode ACK / NACK information for a downlink data channel between multiple CCs to generate multi-bit ACK / NACK information, and transmit the multi-bit ACK / NACK information in the uplink. In this case, the shortened format is applied only to users who simultaneously transmit ACK / NACK information of multiple bits and SRS (Sounding Reference Signal) for channel quality measurement in the same subframe, and CS (Cyclic Shift) based code multiplexing ACK / NACK information notification method that maintains orthogonality between users.

  FIG. 5 is a conceptual diagram in which ACK / NACK information is orthogonalized between users by CS-based code multiplexing. A shortened format in which the last symbol for ACK / NACK information in the subframe is puncture is applied to user #p that simultaneously transmits ACK / NACK information of multiple bits and SRS in the same subframe. The SRS is transmitted at the last symbol position deleted in the frame. Also, a normal format in which the final symbol for ACK / NACK information in the subframe is not deleted is applied to user #q that does not transmit ACK / NACK information and SRS of multiple bits in the same subframe at the same time.

Different cyclic shifts Δp and Δq are assigned to the same CAZAC sequence (the same root sequence) for each of users #p and #q. User #p maps the CAZAC sequence (cyclic shift Δp) to the four symbols for ACK / NACK information in the short format, and maps the SRS to the final symbol of the subframe. User #q maps the CAZAC sequence (cyclic shift Δq) to five symbols for ACK / NACK information in the normal format. Each CAZAC sequence mapped to a symbol for ACK / NACK information is block-modulated by an ACK / NACK signal sequence (UE # p = p _{1 to} p ₄ , UE # q = q _{1 to} q ₅ ) after data modulation.

  Thereby, when ACK / NACK information is orthogonal between users by CS-based code multiplexing, SRS can be mapped and transmitted in the same subframe, and the orthogonality between users can be maintained.

  Another aspect of the present invention is to jointly encode ACK / NACK information for a downlink data channel between multiple CCs to generate multi-bit ACK / NACK information, and transmit the multi-bit ACK / NACK information in the uplink. In this case, the shortened format is applied only to users who simultaneously transmit multi-bit ACK / NACK information and SRS for channel quality measurement in the same subframe, and ACK that maintains orthogonality between users by OCC-based code multiplexing. / NACK information notification method.

  FIG. 6 is a conceptual diagram in which ACK / NACK information is orthogonalized between users by OCC-based code multiplexing. A shortened format in which the last symbol for ACK / NACK information in the subframe is puncture is applied to user #p that simultaneously transmits ACK / NACK information of multiple bits and SRS in the same subframe. The SRS is transmitted at the last symbol position deleted in the frame. In addition, a normal format in which the final symbol for ACK / NACK information in a subframe is not deleted is applied to user #q that does not simultaneously transmit ACK / NACK information and SRS of multiple bits in the same subframe. The last symbol in the subframe is not transmitted. If the OCC sequence length differs between users, the orthogonality between users is lost. In order to maintain orthogonality, it is necessary to match the number of symbols to which the ACK / NACK signal sequence is mapped between users. For this reason, one symbol of user #q that does not transmit SRS is not transmitted.

  Thereby, when ACK / NACK information is orthogonal between users by OCC-based code multiplexing, SRS can be mapped and transmitted in the same subframe, and the orthogonality between users can be maintained.

[Control of number of bits of ACK / NACK information when PUCCH is transmitted simultaneously with PUSCH]
In LTE (Rel. 8), when ACK / NACK (PUCCH) and data (PUSCH) are transmitted in the same subframe, ACK / NACK (PUCCH) is time-multiplexed and transmitted in PUSCH.

  When transmitting ACK / NACK information of multiple bits formed by jointly encoding ACK / NACK information of multiple CCs in uplink, as in LTE (Rel. 8), as shown in FIG. And a method of simultaneous transmission in time multiplexing and a method of simultaneous transmission of PUCCH and PUSCH as shown in FIG. In any of the methods, there is a possibility that the data throughput deteriorates as the number of bits of the ACK / NACK information increases.

According to another aspect of the present invention, ACK / NACK information for a downlink data channel is jointly encoded between a plurality of CCs to generate a plurality of bits of ACK / NACK information. This is a notification method of ACK / NACK information that limits the number of bits of ACK / NACK information when transmitting simultaneously in the same subframe as (PUSCH).
By applying spatial bundling, each state is encoded such that when two codewords are transmitted, ACK is returned only when both of the two codewords are ACK, and NACK is returned otherwise.

  Thereby, the encoded data of ACK / NACK information can be reduced to 2 states (1 bit) irrespective of the number of codewords per CC. For example, even if the number of CC aggregations is 5, the maximum number of encoded bits can be suppressed to 5 bits.

  Alternatively, CC bundling is applied, and each state is encoded so that ACK is returned only when all CCs are ACK, and NACK is returned otherwise.

  Thereby, the encoded data of the ACK / NACK information can be reduced to a total of 1-2 bits regardless of the number of CCs.

  Further, DTX is reduced to reduce it to 2 states (1 bit) when transmitting one code word, and to 4 states (2 bits) when transmitting 2 code words. Thereby, even if it is 5 CC, it can be suppressed to a maximum of 10 bits.

(Embodiment 1)
In this embodiment, when uplink control information is transmitted from the mobile terminal apparatus in the uplink, a plurality of users are orthogonally multiplexed using a cyclic shift of the CAZAC code sequence, and an ACK / NACK signal that is feedback control information Will be described.

  FIG. 8 is a diagram illustrating a schematic configuration of the mobile terminal apparatus according to Embodiment 1 of the present invention. The mobile terminal apparatus shown in FIG. 8 includes a transmission unit and a reception unit. The transmission unit includes an ACK / NACK signal processing unit 100, a reference signal processing unit 101, and a time multiplexing unit 102 that time-multiplexes the ACK / NACK signal and the reference signal. Although the processing block for transmitting data (PUSCH) is not shown in the functional block of the transmission unit, the data (PUSCH) is multiplexed by the time multiplexing unit 102.

  The ACK / NACK signal processing unit 100 includes a CAZAC code generation unit 1001 that generates a CAZAC code sequence corresponding to the CAZAC number, a channel encoding unit 1003 that performs error correction encoding on the ACK / NACK bit sequence, and data modulation that performs data modulation. Unit 1004, a block modulation unit 1002 that performs block modulation on the generated CAZAC code sequence with a data-modulated signal, a cyclic shift unit 1005 that performs cyclic shift on the block-modulated signal, and a signal after cyclic shift. It includes a subcarrier mapping unit 1006 that maps to a carrier, an IFFT unit 1007 that performs inverse fast Fourier transform (IFFT) on the mapped signal, and a CP adding unit 1008 that adds CP (Cyclic Prefix) to the signal after IFFT.

  The reference signal processing unit 101 includes a CAZAC code generation unit 1011 that generates a CAZAC code sequence corresponding to a CAZAC number, a cyclic shift unit 1012 that performs a cyclic shift on a reference signal configured by the CAZAC code sequence, and a post-cyclic shift Block spreading unit 1013 that performs block spreading (multiply by orthogonal codes) on the signal of the signal, subcarrier mapping unit 1014 that maps the signal after block spreading to the subcarrier, IFFT unit 1015 that performs IFFT on the signal after mapping, and IFFT A CP assigning unit 1016 for assigning a CP to a later signal. The uplink reference signal includes SRS and RS. SRS is a reference signal for estimating the uplink channel state of each UE necessary for scheduling (and timing control) at the base station, and is used as the last SC-FDMA symbol in the second slot independently of PUSCH and PUCCH. Is multiplexed. The RS is multiplexed on the second symbol and the sixth symbol of each slot.

  The mobile terminal apparatus determines ACK / NACK for a signal received on the downlink shared data channel (PDSCH), and generates an ACK / NACK bit sequence corresponding thereto. The data modulation unit 1004 of the ACK / NACK signal processing unit 100 modulates the ACK / NACK bit sequence channel-coded by the channel coding unit 1003 into a polar coordinate component signal. Data modulation section 1004 outputs the data-modulated signal to block modulation section 1002. The CAZAC code generation unit 1001 prepares a CAZAC code sequence corresponding to the CAZAC number assigned to the user. The CAZAC code generation unit 1001 outputs the generated CAZAC code sequence to the block modulation unit 1002. The block modulation unit 1002 performs block modulation on the CAZAC code sequence for each time block corresponding to the 1SC-FDMA symbol with the control signal after data modulation. Block modulation section 1002 outputs the signal after block modulation to cyclic shift section 1005.

  Cyclic shift section 1005 cyclically shifts the time domain signal by a predetermined cyclic shift amount. Note that the cyclic shift amount differs for each user and is associated with a cyclic shift number. Cyclic shift section 1005 outputs the signal after cyclic shift to subcarrier mapping section 1006. Subcarrier mapping section 1006 maps the signal after the cyclic shift to a subcarrier based on the resource mapping information. Subcarrier mapping section 1006 outputs the mapped signal to IFFT section 1007.

  The IFFT unit 1007 performs IFFT on the mapped signal and converts it into a time domain signal. IFFT section 1007 outputs the signal after IFFT to CP giving section 1008. CP assigning section 1008 assigns a CP to the mapped signal. CP assigning section 1008 outputs a signal provided with CP to time multiplexing section 102.

  The CAZAC code generation unit 1011 of the reference signal processing unit 101 prepares a CAZAC code sequence corresponding to the CAZAC number assigned to the user and uses it as a reference signal. The CAZAC code generation unit 1011 outputs the reference signal to the cyclic shift unit 1012.

  Cyclic shift section 1012 shifts the time domain reference signal by a predetermined cyclic shift amount. Note that the cyclic shift amount differs for each user and is associated with a cyclic shift number. Cyclic shift section 1012 outputs the reference signal after the cyclic shift to block spreading section 1013. The block spreading unit (orthogonal code multiplication means) 1013 multiplies the reference signal after the cyclic shift by an orthogonal code (OCC) ({1, 1}, {1, -1}) (block spreading). Here, the OCC (block spreading code number) used for the reference signal may be notified from the upper layer by RRC signaling or the like, or the OCC previously associated with the CS of the data symbol may be used. Block spreading section 1013 outputs the signal after block spreading to subcarrier mapping section 1014.

  The subcarrier mapping unit 1014 maps the frequency domain signal to the subcarrier based on the resource mapping information. Subcarrier mapping section 1014 outputs the mapped reference signal to IFFT section 1015. The IFFT unit 1015 performs IFFT on the mapped signal and converts it into a time domain reference signal. IFFT section 1015 outputs the reference signal after IFFT to CP adding section 1016. CP assigning section 1016 assigns a CP to the reference signal after orthogonal code multiplication. The CP assigning unit 1016 outputs the reference signal provided with the CP to the time multiplexing unit 102.

  The time multiplexing unit 102 time-multiplexes the uplink control signal from the ACK / NACK signal processing unit 100 and the reference signal from the reference signal processing unit 101 to obtain a transmission signal including the uplink control channel signal. The present invention applies a shortened format in which the final symbol of a subframe is reduced to a user in which ACK / NACK information and SRS are transmitted simultaneously (time multiplexed in the same subframe), and deletes the final symbol position. SRS is inserted into (Fig. 5). For a user who does not transmit SRS at the same time, a normal format in which the final symbol of the subframe is not reduced is applied even if it is a subframe in which another user may simultaneously transmit SRS.

As shown in FIG. 5, in the case of a user to which the shortened format is applied, the number of symbols that are block-modulated with ACK / NACK information in one time slot is 4 symbols, so that only the ACK / NACK signal sequence for the user is p. consisting of ₁ to _{p 4.} Since other users have 5 symbols that are block-modulated with ACK / NACK information in one time slot, they are ACK / NACK signal sequences q ₁ to q _{5 of} other users.

  The receiving unit determines ACK / NACK based on the OFDM signal demodulating unit 103 that demodulates the OFDM signal, the BCH (Broadcast Channel) signal, the BCH signal that decodes the downlink control signal, the downlink control signal decoding unit 104, and the downlink signal. An ACK / NACK determination unit 105 and an ACK / NACK signal encoding unit 106 are included.

  The OFDM signal demodulation unit 103 receives and demodulates the downlink OFDM signal. That is, CP is removed from the downlink OFDM signal, fast Fourier transform is performed, subcarriers to which the BCH signal or downlink control signal is assigned are extracted, and data demodulation is performed. OFDM signal demodulation section 103 outputs the signal after data demodulation to BCH signal and downlink control signal decoding section 104. Further, OFDM signal demodulation section 103 outputs the downlink signal to ACK / NACK determination section 105.

  The BCH signal and downlink control signal decoding section 104 decodes the signal after data demodulation to obtain a CAZAC number, resource mapping information (including resource block number), a cyclic shift number, and a block spreading code number. BCH signal and downlink control signal decoding section 104 outputs the CAZAC number to CAZAC code generation sections 1001 and 1011, outputs resource mapping information to subcarrier mapping sections 1006 and 1014, and cyclic shift numbers to cyclic shift sections 1005 and 1012. The block spreading code number (OCC number) is output to the block spreading unit 1014.

  The ACK / NACK determination unit 105 determines whether or not the received downlink shared data channel signal (PDSCH signal) can be received without error. If the downlink shared data channel signal can be received without error, an ACK or error is detected. If NACK and downlink shared data channel signal are not detected, each state of DTX is output as a determination result. The ACK / NACK determination unit 105 determines the above three states for each codeword. When transmitting two code words, the above three states are determined for each code word. When a plurality of CCs are allocated for communication with the base station, it is determined whether or not the downlink shared data channel signal can be received without error for each CC.

  The ACK / NACK signal encoding unit 106 receives the determination result determined for each codeword by the ACK / NACK determination unit 105. The ACK / NACK signal encoding unit 106 can encode the determination result using the encoding table shown in FIG. In the case of one code word, information bits are individually assigned to three states of ACK, NACK, and DTX. If the determination result is DTX, it is encoded to “00”, if the determination result is NACK, it is encoded to “01”, and if the determination result is ACK, it is encoded to “10”. In the case of two code words, the number of encoded bits in the state related to DTX is reduced. In the coding table of FIG. 3 (in the case of two codewords), ACK / ACK indicates that the determination results of the two codewords are ACK, and ACK / NACK indicates that the determination result of one codeword is ACK, It shows that the determination result of the other code word is NACK. NACK / ACK indicates that the determination result of one codeword is NACK and the determination result of the other codeword is ACK. Information bits are individually defined for these three states. On the other hand, information bits are not individually defined for DTX. One information bit (00) is assigned to each state of DTX / ACK, DTX / NACK, ACK / DTX, NACK / DTX, DTX / DTX, and NACK / NACK. Since the occurrence probability of DTX or NACK / NACK is low, retransmission is performed in the same manner as NACK / NACK. The state of DTX / DTX may be untransmitted as in LTE.

  Thus, when DTX is included in the determination result of at least one codeword, the number of states that can be notified is limited to four by assigning the same information bits as NACK / NACK, and the NACK / NACK information The maximum number of bits of encoded data is suppressed.

  Alternatively, the individual information bits are determined for the DTX only when the number of CCs is equal to or less than the predetermined number X. However, when the number of CCs is larger than the predetermined number X and when two code words are used, the information bits are not determined by DTX alone. Also good. The ACK / NACK signal encoding unit 106 sets, for example, a threshold number X of CCs = 4. When the number of CCs is 4 or less, 5 states can be notified if the number of codewords is 2 codewords. When the number of CCs exceeds the threshold X and is 5, if the number of codewords is 2 codewords, 4 states are notified. In this case, the maximum number of bits is 10 bits (= 2 × 5).

  Alternatively, when ACK / NACK information is simultaneously transmitted in the same subframe as data (PUSCH) on the uplink, the number of bits of ACK / NACK information may be limited. For each CC, the ACK / NACK signal encoding unit 106 assigns ACK information bits (for example, “0”) to ACK / ACK that is in the ACK state in the case of two codewords for each CC. NACK information bits (for example, “1”) are assigned to all states other than ACK. Thereby, the state that can be notified per CC is reduced to 2 states (1 bit) regardless of the number of code words.

  Alternatively, the ACK / NACK signal encoding unit 106 assigns an ACK information bit (for example, “0”) only to a plurality of CCs when the determination result of all CCs is ACK, and otherwise, NACK information A bit (for example, “1”) may be assigned. Thereby, ACK / NACK information can be reduced to a total of 1-2 bits regardless of the number of CCs.

  Alternatively, the ACK / NACK signal encoding unit 106 does not allocate information bits to the determination result including DTX, and ACK / NACK is in two states (1 bit) for one codeword, and ACK / NACK is used for two codewords. Two information bits may be assigned to four states (2 bits) of ACK, ACK / NACK, NACK / ACK, and NACK / NACK.

  The ACK / NACK signal encoding unit 106 encodes ACK / NACK information of a plurality of CCs at once after reducing the number of bits of ACK / NACK information as described above. A method of collectively encoding ACK / NACK information of multiple CCs is not limited in the present invention. When the number of CC aggregations is 1, ACK / NACK information encoded by the above method is used as it is.

  FIG. 9 is a diagram illustrating a schematic configuration of the radio base station apparatus according to Embodiment 1 of the present invention. The radio base station apparatus shown in FIG. 9 includes a transmission unit and a reception unit. The transmission unit includes an uplink resource allocation information signal generation unit 701, an OFDM signal generation unit 702 that multiplexes another downlink channel signal and an uplink resource allocation information signal to generate an OFDM signal. Other downlink channel signals include data, reference signals, control signals, and the like, and uplink resource allocation information signals include CAZAC numbers, resource mapping information, cyclic shift numbers, and block spreading code numbers (OCC numbers).

  The CAZAC number, resource mapping information, cyclic shift number, and block spreading code number (OCC number) may be transmitted to the mobile terminal apparatus using BCH, and the mobile terminal apparatus may be transmitted using a downlink control channel (PDCCH: Physical Downlink Control Channel). You may send to. Alternatively, the CAZAC number, resource mapping information, cyclic shift number, and block spreading code number (OCC number) may be notified to the mobile terminal apparatus in the upper layer.

  The OFDM signal generation unit 702 maps downlink signals including other downlink channel signals and uplink resource allocation information signals to subcarriers, performs inverse fast Fourier transform (IFFT), and adds a CP by adding a CP. Generate.

  The receiving unit includes a CP removing unit 703 that removes CP from the received signal, an FFT unit 704 that performs fast Fourier transform (FFT) on the received signal, a subcarrier demapping unit 705 that demaps the signal after FFT, A block despreading unit 706 that despreads the demapped signal using a block spreading code (OCC), and a cyclic shift separation unit 707 that removes a cyclic shift from the signal after despreading and separates the target user's signal. A channel estimation unit 708 that performs channel estimation on the demapped signal after user separation, a data demodulation unit 709 that demodulates the signal after subcarrier demapping using the channel estimation value, and a signal after data demodulation And a data decoding unit 710 for data decoding.

  CP removing section 703 removes a portion corresponding to CP and extracts an effective signal portion. CP removing section 703 outputs the signal after CP removal to FFT section 704. The FFT unit 704 performs FFT on the received signal and converts it to a frequency domain signal. FFT section 704 outputs the signal after FFT to subcarrier demapping section 705.

  Subcarrier demapping section 705 extracts an ACK / NACK signal, which is an uplink control channel signal, from the frequency domain signal using resource mapping information. Subcarrier demapping section 705 outputs the extracted ACK / NACK signal to data demodulation section 709. Subcarrier demapping section 705 outputs the extracted reference signal to block despreading section 706.

  In the block despreading section 706, received signals orthogonally multiplexed using block spreading, that is, orthogonal code (OCC) (block spreading code), are converted into orthogonal codes ({1, 1}, {1, -1}). Block despreading section 706 outputs the despread signal to cyclic shift separation section 707.

  Cyclic shift separation section 707 separates control signals orthogonally multiplexed using cyclic shift using cyclic shift numbers. The uplink control channel signal from the mobile terminal apparatus is cyclically shifted with a different cyclic shift amount for each user. Therefore, by performing a cyclic shift in the reverse direction by the same cyclic shift amount as that performed at the mobile terminal apparatus, it is possible to separate the control signal of the user to be subjected to reception processing. Cyclic shift separation section 707 outputs the signal after user separation to channel estimation section 708.

  The channel estimation unit 708 separates the reference signal orthogonally multiplexed using the cyclic shift and the orthogonal code using the cyclic shift number and, if necessary, the OCC number. Channel estimation section 708 performs cyclic shift in the reverse direction using the cyclic shift amount corresponding to the cyclic shift number. Further, despreading is performed using an orthogonal code corresponding to the OCC number. Thereby, it becomes possible to isolate | separate a user's signal (reference signal). Further, the channel estimation unit 708 extracts the reference signal received from the frequency domain signal using the resource mapping information. Then, channel estimation is performed by correlating the CAZAC code sequence corresponding to the CAZAC number with the received CAZAC code sequence.

  Data demodulator 709 demodulates the ACK / NACK signal and outputs the data to data decoder 710. At this time, the data demodulation unit 709 demodulates data based on the channel estimation value from the channel estimation unit 708. Further, data decoding section 710 performs data decoding on the demodulated ACK / NACK signal and outputs it as ACK / NACK information. The data decoding unit 710 decodes the ACK / NACK signal for each CC when the ACK / NACK signals of a plurality of CCs are encoded at once, and further receives the ACK / NACK information encoded for each CC. Decrypt. In the mobile terminal device, if encoding is performed using the encoding table shown in FIG. 3, decoding is performed using the same encoding table. Data demodulating section 709 performs decoding using a decoding method corresponding to the ACK / NACK information encoding method in the mobile terminal apparatus.

(Embodiment 2)
In the present embodiment, when uplink control information is transmitted from the mobile terminal apparatus in the uplink, a plurality of users are orthogonally multiplexed using block spreading and an ACK / NACK signal as feedback control information is transmitted. Will be described.

  FIG. 10 is a diagram illustrating a schematic configuration of the mobile terminal apparatus according to Embodiment 2 of the present invention. The mobile terminal apparatus shown in FIG. 10 includes a transmission unit and a reception unit. The transmission unit includes an ACK / NACK signal processing unit 130, a reference signal processing unit 131, and a time multiplexing unit 132 that time-multiplexes the ACK / NACK signal and the reference signal. Although the processing block for transmitting data (PUSCH) is not shown in the functional block of the transmission unit, the data (PUSCH) is multiplexed by the time multiplexing unit 132.

  The ACK / NACK signal processing unit 130 includes a channel coding unit 1301 that performs error correction coding on the ACK / NACK bit sequence, a data modulation unit 1302 that performs data modulation on the ACK / NACK bit sequence, and DFT ( Discrete Fourier Transform) DFT section 1303, block spreading section 1305 that performs block spreading on the DFT signal using a block spreading code, subcarrier mapping section 1306 that maps the block spread signal to subcarriers, and the mapped signal An IFFT unit 1307 that performs IFFT, and a CP assigning unit 1308 that assigns a CP to the signal after IFFT. Data modulation section 1302, subcarrier mapping section 1306, IFFT section 1307, and CP assignment section 1308 are the same as data modulation section 1004, subcarrier mapping section 1006, IFFT section 1007, and CP assignment section 1008 in Embodiment 1, respectively. Therefore, detailed description thereof is omitted.

  The reference signal processing unit 131 includes a CAZAC code generation unit 1311 that generates a CAZAC code sequence corresponding to the CAZAC number, a cyclic shift unit 1312 that performs a cyclic shift on a reference signal configured by the CAZAC code sequence, and a post-cyclic shift Block spreading unit 1313 that performs block spreading on the signal with a block spreading code, subcarrier mapping unit 1314 that maps the signal after block spreading to a subcarrier, IFFT unit 1315 that performs IFFT on the signal after mapping, and a signal after IFFT And a CP giving unit 1316 for giving a CP. Note that the CAZAC code generation unit 1311, the cyclic shift unit 1312, the block spreading unit 1313, the subcarrier mapping unit 1314, the IFFT unit 1315, and the CP assignment unit 1316 are the CAZAC code generation unit 1011, the cyclic shift unit 1012, and the cyclic shift unit 1012, respectively. Since the block spreading unit 1013, the subcarrier mapping unit 1014, the IFFT unit 1015, and the CP assigning unit 1016 are the same, detailed description thereof is omitted.

  Since the block spreading sections 1305 and 1313 generate a signal for one symbol (12 subcarriers) after DFT, the block spreading sections 1305 and 1313 generate a plurality of symbols and multiply by orthogonal codes. As shown in FIG. 6, the block spreading code W is different for each user and is associated with a block spreading code number. Further, the block spreading unit 1313 multiplies the reference signal after the cyclic shift by a block spreading code (orthogonal code (OCC) ({1, 1}, {1, -1})). Here, as the OCC used for the reference signal, it is preferable to use the OCC previously associated with the block spread code of the data symbol. Block spreading sections 1305 and 1313 output the block spread signals to subcarrier mapping sections 1306 and 1314, respectively.

  The receiving unit includes an OFDM signal demodulating unit 133 that demodulates an OFDM signal, a BCH signal, a BCH signal that decodes a downlink control signal, a downlink control signal decoding unit 134, and a downlink shared data channel signal (PDSCH (Physical Downlink Shared Channel)). Has an ACK / NACK determination unit 135 that determines whether or not an error has been received without error, and an ACK / NACK signal encoding unit 136. The OFDM signal demodulating unit 133 and the BCH signal and the downlink control signal decoding unit 134 are the same as the OFDM signal demodulating unit 103 and the BCH signal and the downlink control signal decoding unit 104 in the first embodiment, respectively. Omitted.

  The ACK / NACK determination unit 135 determines whether or not the received downlink shared data channel signal (PDSCH signal) can be received without error, and outputs a determination result. The determination result has three states of ACK, NACK, and DTX bits. The ACK / NACK determination unit 135 outputs an ACK / NACK / DTX determination result to the ACK / NACK signal encoding unit 136. When downlink shared data channel signals are received in parallel by a plurality of CCs, the above three states are determined for each CC.

  The ACK / NACK signal encoding unit 136 receives the determination result determined for each codeword by the ACK / NACK determination unit 135. The ACK / NACK signal encoding unit 136 has the same function as the ACK / NACK signal encoding unit 106 of the first embodiment. That is, after reducing the number of states that can be individually reported, the states that the ACK / NACK determination unit 135 outputs for each CC corresponding to the multiple downlink shared data channel signals received in parallel by the multiple CCs are collected. Encode.

ACK / NACK signal processing unit 130 is provided with ACK / NACK information encoded in a state where the maximum number of encoded bits is limited in ACK / NACK signal encoding unit 136. Channel coding section 1301 performs error correction coding on ACK / NACK information, duplicates the number of symbols allocated to one slot, and sequentially modulates the duplicated ACK / NACK information (p ₁ to p _{12 in} FIG. 6). Part 1302. The DFT unit 1303 converts the time domain ACK / NACK information into the frequency domain, and then orthogonalizes between users by multiplying the entire duplicate symbol by an orthogonal code (W _p1 to W _p4 ).

  At this time, as shown in FIG. 6, when the SRS is transmitted in the same subframe as the ACK / NACK information, a shortened format in which the last symbol of the subframe is deleted is applied. An SRS is inserted at the end of the shortened format (deleted last symbol position) and transmitted.

  On the other hand, in the format of other users who do not transmit SRS, the last symbol at the same position as SRS is not transmitted. For this reason, the radio base station apparatus transmits UL grant to another user #q so that the other user #q does not transmit ACK / NACK information in the final symbol of the subframe in which the user #p transmits SRS. Instruct. Also, the radio base station apparatus instructs all users #p and #q with UL grant to reduce the sequence length of the orthogonal codes Wp and Wq by one. Thereby, the sequence length of the orthogonal code applied to ACK / NACK information among a plurality of users is uniform among users, and the orthogonality between users is maintained.

  The BCH signal / downlink control signal decoding unit 134 decodes the signal after data demodulation to obtain a CAZAC number, resource mapping information (including resource block number), a cyclic shift number, and a block spreading code number. The BCH signal and downlink control signal decoding unit 134 outputs the CAZAC number to the CAZAC code generation unit 1311, outputs the resource mapping information to the subcarrier mapping units 1306 and 1314, and outputs the cyclic shift number to the cyclic shift unit 1312. The block spreading code number is output to block spreading sections 1305 and 1313.

  In the mobile terminal apparatus configured as described above, the ACK / NACK bit sequence output from the ACK / NACK determination unit 135 is the maximum number of encoded bits in the ACK / NACK signal encoding unit 136 as in the first embodiment. Are encoded in a restricted state. In the case of multiple CCs, ACK / NACK information is encoded at once.

  As long as it does not deviate from the scope of the present invention, the number of processing units and processing procedures in the above description can be appropriately changed and implemented. Each element shown in the figure represents a function, and each functional block may be realized by hardware or software. Other modifications can be made without departing from the scope of the present invention.

100, 130 ACK / NACK signal processing unit 101, 131 Reference signal processing unit 102, 132 Time multiplexing unit 103, 133 OFDM signal demodulation unit 104, 134 BCH signal, downlink control signal decoding unit 105, 135 ACK / NACK determination unit 106, 136 ACK / NACK signal encoding unit 701 uplink resource allocation information signal generation unit 702 OFDM signal generation unit 703 CP removal unit 704 FFT unit 705 subcarrier demapping unit 706 block despreading unit 707 cyclic shift demultiplexing unit 708 channel estimation unit 709 data Demodulator 710 Data decoder 1001, 1011, 1311 CAZAC code generator 1002 Block modulator 1003, 1301 Channel encoder 1004, 1302 Data modulator 1005, 1012, 1312 Cyclic Shift unit 1006, 1014, 1306, 1314 Subcarrier mapping unit 1007, 1015, 1307, 1315 IFFT unit 1008, 1016, 1308, 1316 CP assigning unit 1013, 1305, 1313 Block spreading unit

Claims (9)

An ACK / NACK signal encoding unit that jointly encodes ACK / NACK information for a downlink shared data channel signal between a plurality of basic frequency blocks to generate a plurality of bits of ACK / NACK information;
A channel coding unit for channel-coding the ACK / NACK information of the plurality of bits;
A DFT unit that performs DFT (Discrete Fourier Transform) on the channel-encoded signal;
A block spreading unit that performs block spreading on the signal after DFT with a block spreading code,
The block spreading unit transmits a subframe when the multi-bit ACK / NACK information is transmitted in a subframe in which symbols for transmitting a channel quality measurement SRS (Sounding Reference Signal) are time-multiplexed. When a shortened format in which one of the symbols for ACK / NACK information is deleted is applied, the multi-bit ACK / NACK information is transmitted in a subframe that does not include a symbol for transmitting the SRS. Is applied with a normal format in which the number of symbols is not deleted.   And a multiplexing unit for multiplexing the ACK / NACK information on the first symbol, the third symbol to the fifth symbol, and the seventh symbol, and multiplexing the reference signal on the second symbol and the sixth symbol. The mobile terminal device according to claim 1.   The ACK / NACK signal encoding unit is capable of individually reporting the ACK, NACK, and DTX states for a plurality of downlink shared data channel signals received in parallel at a plurality of basic frequency blocks for each basic frequency block. The mobile terminal apparatus according to claim 1, wherein encoding is performed in a lump after reducing the number of the mobile terminals.   The ACK / NACK signal encoding unit allocates information bits individually for the three states of ACK, NACK, and DTX per basic frequency block in the case of 1 codeword transmission, and is independent for DTX in the case of 2 codeword transmission. The mobile terminal apparatus according to claim 3, wherein the number of states is reduced without assigning information bits.   The ACK / NACK signal encoding unit assigns an information bit independently to DTX only when the number of basic frequency blocks is equal to or less than a predetermined value, and separately for DTX when the number of basic frequency blocks is larger than a predetermined value. The mobile terminal apparatus according to claim 3, wherein the number of states is reduced without assigning information bits. A wireless communication method between a mobile terminal device and a wireless base station device,
A step of jointly encoding ACK / NACK information for a downlink shared data channel signal between a plurality of basic frequency blocks to generate a plurality of bits of ACK / NACK information; a step of channel-coding the plurality of bits of ACK / NACK information; And, after performing DFT (Discrete Fourier Transform) on the channel-coded encoded data, block spreading with a block spreading code,
When the multi-bit ACK / NACK information is transmitted in a subframe in which symbols for transmitting channel quality measurement SRS (Sounding Reference Signal) are time-multiplexed, ACK / NACK information in the subframe When a shortened format in which one of the symbols is deleted is applied and the multi-bit ACK / NACK information is transmitted in a subframe that does not include a symbol for transmitting the SRS, the number of symbols A wireless communication method characterized by applying a normal format that is not deleted.   The ACK / NACK information is multiplexed on the first symbol, the third symbol to the fifth symbol, and the seventh symbol, and the reference signal is multiplexed on the second symbol and the sixth symbol. Wireless communication method. A wireless communication system comprising a mobile terminal device and a wireless base station device,
The mobile terminal apparatus jointly encodes ACK / NACK information for a downlink shared data channel signal transmitted from the radio base station apparatus between a plurality of basic frequency blocks to generate ACK / NACK information of multiple bits. A signal encoding unit; a channel encoding unit that performs channel encoding on the multi-bit ACK / NACK information; a DFT unit that performs DFT (Discrete Fourier Transform) on the channel encoded signal; and a block after the DFT signal A block spreading unit that performs block spreading with a spreading code,
The block spreading unit transmits a subframe when the multi-bit ACK / NACK information is transmitted in a subframe in which symbols for transmitting a channel quality measurement SRS (Sounding Reference Signal) are time-multiplexed. When a shortened format in which one of the symbols for ACK / NACK information is deleted is applied, the multi-bit ACK / NACK information is transmitted in a subframe that does not include a symbol for transmitting the SRS. In the radio communication system, a normal format in which the number of symbols is not deleted is applied. The mobile terminal apparatus further includes a multiplexing unit that multiplexes the ACK / NACK information into the first symbol, the third symbol to the fifth symbol, and the seventh symbol, and multiplexes the reference signal into the second symbol and the sixth symbol. The wireless communication system according to claim 8, further comprising:

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