Base station device and wireless communication method

The present invention relates to a base station apparatus and a wireless communication method.

In mobile communication, ARQ (Automatic Repeat Request) is applied to downlink data from a wireless communication base station device (hereinafter abbreviated as a base station) to a wireless communication mobile station device (hereinafter abbreviated as a mobile station). Will be done. That is, the mobile station feeds back the response signal indicating the error detection result of the downlink data to the base station. The mobile station performs CRC (Cyclic Redundancy Check) on the downlink data, and if CRC = OK (no error), ACK (Acknowledgment), and if CRC = NG (error), NACK (Negative Acknowledgment). It feeds back to the base station as a response signal. This response signal is transmitted to the base station using an uplink control channel such as PUCCH (Physical Uplink Control Channel).

In addition, the base station transmits control information for notifying the resource allocation result of downlink data to the mobile station. This control information is transmitted to the mobile station using a downlink control channel such as L1 / L2 CCH (L1 / L2 Control Channel). Each L1 / L2CCH occupies one or more CCEs. When one L1 / L2CCH occupies a plurality of CCEs (Control Channel Elements), one L1 / L2CCH occupies a plurality of consecutive CCEs. According to the number of CCEs required to notify the control information, the base station assigns one of the L1 / L2CCHs among the multiple L1 / L2CCHs to each mobile station, and the CCE (Control Channel Element) occupied by each L1 / L2CCH. ), Map the control information to the physical resource and send it.

In addition, in order to efficiently use downlink communication resources, it is being considered to associate CCE with PUCCH. According to this association, each mobile station can determine the PUCCH used for transmitting the response signal from its own station from the CCE corresponding to the physical resource to which the control information to its own station is mapped.

Further, as shown in FIG. 1, it has been studied to code-multiplex a plurality of response signals from a plurality of mobile stations by spreading them using a ZC (Zadoff-Chu) series and a Walsh series (Walsh series). See Non-Patent Document 1). In Figure 1 (W₀, W₁, W₂, W₃) Represents the Walsh series with a series length of 4. As shown in FIG. 1, in the mobile station, the ACK or NACK response signal is first first diffused in one symbol by the ZC sequence (series length 12) on the frequency axis. Next, the response signal after the primary diffusion is W₀~ W₃IFFT (Inverse Fast Fourier Transform) is performed corresponding to each. The response signal diffused by the ZC sequence having a sequence length of 12 on the frequency axis is converted by this IFFT into a ZC sequence having a sequence length of 12 on the time axis. Then, the signal after IFFT is further secondarily diffused using the Walsh sequence (series length 4). That is, one response signal has four symbols S₀~ S₃Are placed in each. Similarly, in other mobile stations, the response signal is spread using the ZC series and the Walsh series. However, between different mobile stations, ZC series having different Cyclic Shift amounts on the time axis or Walsh series having different amounts from each other are used. Here, since the series length of the ZC series on the time axis is 12, 12 ZC series having a cyclic shift amount of 0 to 11 generated from the same ZC series can be used. Moreover, since the series length of the Walsh series is 4, four Walsh series different from each other can be used. Therefore, in an ideal communication environment, response signals from a maximum of 48 (12 × 4) mobile stations can be code-multiplexed.

Here, the cross-correlation between ZC series having different cyclic shift amounts generated from the same ZC series is 0. Therefore, in an ideal communication environment, as shown in FIG. 2, a plurality of response signals diffused and code-multiplexed in ZC series (circular shift amounts 0 to 11) having different cyclic shift amounts are correlated at the base station. By processing, it can be separated on the time axis without intersymbol interference.

However, due to the influence of transmission timing shift in the mobile station, delay wave due to multipath, frequency offset, etc., a plurality of response signals from a plurality of mobile stations do not always reach the base station at the same time. For example, as shown in FIG. 3, when the transmission timing of the response signal diffused in the ZC series with a cyclic shift amount of 0 is delayed from the correct transmission timing, the correlation peak of the ZC series with a cyclic shift amount of 0 is the cyclic shift amount 1. Appears in the detection window of the ZC series. Further, as shown in FIG. 4, when the response signal diffused in the ZC series having a circulation shift amount of 0 has a delay wave, interference leakage due to the delay wave appears in the detection window of the ZC series having a circulation shift amount of 1. It ends up. That is, in these cases, the ZC series having a cyclic shift amount of 1 receives interference from the ZC series having a circular shift amount of 0. Therefore, in these cases, the separation characteristic between the response signal diffused in the ZC series having a circulation shift amount of 0 and the response signal diffused in the ZC series having a circulation shift amount of 1 deteriorates. That is, if ZC series having cyclic shift amounts adjacent to each other are used, the separation characteristic of the response signal may deteriorate.

Therefore, conventionally, when a plurality of response signals are code-multiplexed by spreading the ZC series, the difference in the amount of cyclic shift (circular shift interval) sufficient to prevent intersymbol interference between the ZC series is set in the ZC series. It is provided in between. For example, assuming that the difference in the cyclic shift amount between the ZC series is 4, only the three ZC series with the cyclic shift amounts 0, 4, and 8 out of the 12 ZC series with the cyclic shift amounts 0 to 11 are the primary response signals. Used for diffusion. Therefore, when a Walsh sequence having a sequence length of 4 is used for the secondary diffusion of the response signal, the response signal from a mobile station with a maximum of 12 (3 × 4) can be code-multiplexed.

<p><nplcit num="1"><text>Multiplexing capability of CQIs and ACK / NACKs form different UEs (ftp://ftp.3gpp.org/TSG_RAN/WG1_RL1/TSGR1_49/Docs/R1-072315.zip)</text></nplcit></p>

<p> As mentioned above, the Walsh series with a series length of 4 (W) for secondary diffusion₀, W₁, W₂, W₃), One response signal has four symbols (S)₀~ S₃) Are placed respectively. Therefore, in a base station that receives a response signal from a mobile station, it is necessary to back-diffuse the response signal over a 4-symbol time. On the other hand, when the mobile station moves at high speed, there is a high possibility that the propagation path state between the mobile station and the base station will change during the above four symbol times. Therefore, in the presence of a mobile station that moves at high speed, the orthogonality between the Walsh series used for secondary diffusion may be disrupted. That is, in the presence of a mobile station that moves at high speed, intersymbol interference between the Walsh series is more likely to occur than intersymbol interference between the ZC series, and as a result, the separation characteristics of the response signal deteriorate. ..</p><p> If some of the mobile stations move at high speed and the other mobile stations are stationary, the mobile stations that move at high speed and the stationary mobile stations that are multiplexed on the Walsh axis may also be present. Affected by intersymbol interference.</p><p> An object of the present invention is to provide a base station apparatus and a wireless communication method capable of minimizing deterioration of the separation characteristic of a code-multiplexed response signal.</p>

<p> The wireless communication device according to one of the aspects of the present invention includes a first spreading means for first-diffusing a response signal using any of a plurality of first series that can be separated from each other by different circulation shift amounts, and a primary spreading means. A second diffusion means for secondarily diffusing the spread response signal using any of a plurality of second sequences, and a cyclic shift between the first sequences combined with different second sequences adjacent to each other. The difference in quantity is smaller than the difference in the amount of cyclic shift between the first series combined with the same second series.</p>

<p> According to the present invention, deterioration of the separation characteristic of the response signal code-multiplexed can be minimized.</p>

<figref num="1">The figure which shows the diffusion method of a response signal (conventional)</figref><figref num="2">Diagram showing the correlation processing of response signals spread in the ZC series (in the case of an ideal communication environment)</figref><figref num="3">Diagram showing correlation processing of response signals spread in ZC series (when there is a deviation in transmission timing)</figref><figref num="4">Diagram showing the correlation processing of the response signal spread in the ZC series (when there is a delayed wave)</figref><figref num="5">Block diagram showing the configuration of the base station according to the first embodiment of the present invention.</figref><figref num="6">A block diagram showing a configuration of a mobile station according to the first embodiment of the present invention.</figref><figref num="7">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 1 of this invention (the 1).</figref><figref num="8">The figure which shows the correspondence between the 1st series, the 2nd series and PUCCH which concerns on Embodiment 1 of this invention.</figref><figref num="9">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 1 of this invention (the 2)</figref><figref num="10">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 1 of this invention (the 3)</figref><figref num="11">Walsh series according to Embodiment 2 of the present invention</figref><figref num="12">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 2 of this invention.</figref><figref num="13">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 3 of this invention (the 1)</figref><figref num="14">The figure which shows the correspondence between ZC series, Walsh series and PUCCH which concerns on Embodiment 3 of this invention (the 2)</figref><figref num="15">The figure which shows the diffusion method of a reference signal</figref>

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

(Embodiment 1) The configuration of the base station 100 according to the present embodiment is shown in FIG. 5, and the configuration of the mobile station 200 according to the present embodiment is shown in FIG.

In order to avoid complicating the explanation, FIG. 5 shows a component related to transmission of downlink data closely related to the present invention and reception of a response signal to the downlink data on the uplink. It will be shown and the illustration and description of the components related to the reception of uplink data will be omitted. Similarly, FIG. 6 shows a component related to reception of downlink data closely related to the present invention and transmission of a response signal to the downlink data on the uplink, and a configuration related to transmission of uplink data. Illustration and description of parts will be omitted.

Further, in the following description, a case where the ZC series is used for the primary diffusion and the Walsh series is used for the secondary diffusion will be described. However, for the primary diffusion, a series other than the ZC series, which can be separated from each other by different cyclic shift amounts, may be used. Similarly, an orthogonal series other than the Walsh series may be used for the secondary diffusion.

In the following explanation, the ZC series with a series length of 12 and the Walsh series with a series length of 4 (W)₀, W₁, W₂, W₃) Will be described. However, the present invention is not limited to these series lengths.

In the following explanation, 12 ZCs with cyclic shift amounts 0 to 11 are referred to as ZC # 0 to ZC # 11, respectively, and the four Walsh series with series numbers 0 to 3 are W # 0 to W # 3, respectively. Notated as.

In the following explanation, L1 / L2CCH # 1 is CCE # 1, L1 / L2CCH # 2 is CCE # 2, L1 / L2CCH # 3 is CCE # 3, and L1 / L2CCH # 4 is CCE # 4 and CCE # 5. , L1 / L2CCH # 5 shall occupy CCE # 6 and CCE # 7, L1 / L2CCH # 6 shall occupy CCE # 8 ~ CCE # 11 ..., respectively.

Further, in the following description, it is assumed that the CCE number and the PUCCH number defined by the cyclic shift amount of the ZC series and the Walsh series number are associated with each other on a one-to-one basis. That is, CCE # 1 and PUCCH # 1, CCE # 2 and PUCCH # 2, CCE # 3 and PUCCH # 3 ... correspond to each other.

In the base station 100 shown in FIG. 5, the resource allocation result of downlink data is input to the control information generation unit 101 and the mapping unit 104.

The control information generation unit 101 generates control information for notifying the resource allocation result for each mobile station and outputs the control information to the coding unit 102. The control information for each mobile station includes mobile station ID information indicating which mobile station the control information is addressed to. For example, the CRC masked by the ID number of the mobile station to which the control information is notified is included in the control information as the mobile station ID information. The control information for each mobile station is encoded by the coding unit 102, modulated by the modulation unit 103, and input to the mapping unit 104. Further, the control information generation unit 101 assigns one of a plurality of L1 / L2CCHs to each mobile station according to the number of CCEs required to notify the control information, and assigns the assigned L1 / L2CCH to the assigned L1 / L2CCH. The corresponding CCE number is output to the mapping unit 104. For example, since the number of CCEs required to notify the mobile station # 1 of control information is 1, when L1 / L2CCH # 1 is assigned to the mobile station # 1, the control information generator 101 has the CCE number # 1. 1 is output to the mapping unit 104. Further, since the number of CCEs required to notify the mobile station # 1 of control information is 4, when L1 / L2CCH # 6 is assigned to the mobile station # 1, the control information generation unit 101 is assigned the CCE number # 1. Outputs 8 to # 11 to the mapping unit 104.

On the other hand, the coding unit 105 encodes the transmission data (downlink data) to each mobile station and outputs it to the retransmission control unit 106.

At the time of initial transmission, the retransmission control unit 106 holds the encoded transmission data for each mobile station and outputs the encoded data to the modulation unit 107. The retransmission control unit 106 holds the transmission data until the ACK from each mobile station is input from the determination unit 116. Further, the retransmission control unit 106 outputs the transmission data corresponding to the NACK to the modulation unit 107 when the NACK from each mobile station is input from the determination unit 116, that is, at the time of retransmission.

The modulation unit 107 modulates the encoded transmission data input from the retransmission control unit 106 and outputs it to the mapping unit 104.

When the control information is transmitted, the mapping unit 104 maps the control information input from the modulation unit 103 to physical resources according to the CCE number input from the control information generation unit 101 and outputs the control information to the IFFT unit 108. That is, the mapping unit 104 maps the control information for each mobile station to the subcarriers corresponding to the CCE numbers in the plurality of subcarriers constituting the OFDM symbol.

On the other hand, when transmitting downlink data, the mapping unit 104 maps the data transmitted to each mobile station to physical resources according to the resource allocation result and outputs the data to the IFFT unit 108. That is, the mapping unit 104 maps the transmission data for each mobile station to any of the plurality of subcarriers constituting the OFDM symbol according to the resource allocation result.

The IFFT unit 108 performs IFFT on a plurality of subcarriers to which control information or transmission data is mapped to generate an OFDM symbol, and outputs the OFDM symbol to the CP (Cyclic Prefix) addition unit 109.

The CP addition unit 109 adds the same signal as the tail portion of the OFDM symbol to the beginning of the OFDM symbol as a CP.

The radio transmission unit 110 performs transmission processing such as D / A conversion, amplification, and up-conversion on the OFDM symbol after CP addition, and transmits the OFDM symbol from the antenna 111 to the mobile station 200 (FIG. 6).

On the other hand, the wireless reception unit 112 receives the response signal transmitted from the mobile station 200 via the antenna 111, and performs reception processing such as down-conversion and A / D conversion on the response signal.

The CP removing unit 113 removes the CP added to the response signal after the reception processing.

The despreading unit 114 despreads the response signal in the Walsh series used for the secondary diffusion in the mobile station 200, and outputs the response signal after despreading to the correlation processing unit 115.

The correlation processing unit 115 obtains and determines the correlation value between the response signal input from the despreading unit 114, that is, the response signal diffused in the ZC series and the ZC series used for the primary diffusion in the mobile station 200. Output to unit 116.

The determination unit 116 detects the response signal for each mobile station by detecting the correlation peak for each mobile station using the detection window set for each mobile station on the time axis. For example, when the correlation peak is detected in the detection window # 1 for the mobile station # 1, the determination unit 116 detects the response signal from the mobile station # 1. Then, the determination unit 116 determines whether the detected response signal is ACK or NACK, and outputs the ACK or NACK for each mobile station to the retransmission control unit 106.

On the other hand, in the mobile station 200 shown in FIG. 6, the radio receiving unit 202 receives the OFDM symbol transmitted from the base station 100 via the antenna 201, and receives processing such as down-conversion and A / D conversion for the OFDM symbol. I do.

The CP removal unit 203 removes the CP added to the OFDM symbol after the reception processing.

The FFT (Fast Fourier Transform) unit 204 performs FFT on the OFDM symbol to obtain control information or downlink data mapped to a plurality of subcarriers, and outputs them to the extraction unit 205.

When the extraction unit 205 receives the control information, the extraction unit 205 extracts the control information from the plurality of subcarriers and outputs the control information to the demodulation unit 206. This control information is demodulated by the demodulation unit 206, decoded by the decoding unit 207, and input to the determination unit 208.

On the other hand, when receiving the downlink data, the extraction unit 205 extracts the downlink data addressed to its own station from a plurality of subcarriers according to the resource allocation result input from the determination unit 208 and outputs the downlink data to the demodulation unit 210. This downlink data is demodulated by the demodulation unit 210, decoded by the decoding unit 211, and input to the CRC unit 212.

The CRC unit 212 performs error detection using CRC on the downlink data after decoding, and responds with ACK when CRC = OK (no error) and NACK when CRC = NG (with error). It is generated as a signal, and the generated response signal is output to the modulation unit 213. Further, when CRC = OK (no error), the CRC unit 212 outputs the decoded downlink data as received data.

The determination unit 208 blindly determines whether or not the control information input from the decoding unit 207 is the control information addressed to its own station. For example, the determination unit 208 determines that the control information for which CRC = OK (no error) is obtained by demasking with the ID number of the own station is the control information addressed to the own station. Then, the determination unit 208 outputs the control information addressed to the own station, that is, the resource allocation result of the downlink data for the own station to the extraction unit 205. Further, the determination unit 208 determines the PUCCH used for transmitting the response signal from the own station from the CCE number corresponding to the subcarrier to which the control information addressed to the own station is mapped, and controls the determination result (PUCCH number). Output to unit 209. For example, the determination unit 208 of the mobile station 200 to which the above L1 / L2CCH # 1 is assigned has PUCCH # 1 corresponding to CCE # 1 because the control information is mapped to the subcarrier corresponding to CCE # 1. Judge as PUCCH for station. Further, since the control information is mapped to the subcarriers corresponding to CCE # 8 to CCE # 11 in the determination unit 208 of the mobile station 200 to which the above L1 / L2CCH # 6 is assigned, CCE # 8 to CCE # 11 In, PUCCH # 8 corresponding to the minimum number CCE # 8 is determined to be PUCCH for own station.

The control unit 209 controls the circulation shift amount of the ZC series used for the primary diffusion in the diffusion unit 214 and the Walsh series used for the secondary diffusion in the diffusion unit 217 according to the PUCCH number input from the determination unit 208. That is, the control unit 209 sets the ZC sequence of the circulation shift amount corresponding to the PUCCH number input from the determination unit 208 to the diffusion unit 214, and sets the Walsh series corresponding to the PUCCH number input from the determination unit 208 to the diffusion unit. Set to 217. The details of the sequence control by the control unit 209 will be described later.

The modulation unit 213 modulates the response signal input from the CRC unit 212 and outputs it to the diffusion unit 214.

As shown in FIG. 1, the spreading unit 214 primary-spreads the response signal in the ZC series set by the control unit 209, and outputs the response signal after the primary spreading to the IFFT unit 215.

As shown in FIG. 1, the IFFT unit 215 performs IFFT on the response signal after the primary diffusion, and outputs the response signal after IFFT to the CP addition unit 216.

The CP addition unit 216 adds the same signal as the tail portion of the response signal after IFFT as a CP to the beginning of the response signal.

As shown in FIG. 1, the diffusion unit 217 secondarily diffuses the response signal after CP addition in the Walsh series set by the control unit 209, and outputs the response signal after the second diffusion to the radio transmission unit 218. ..

The radio transmission unit 218 performs transmission processing such as D / A conversion, amplification, and up-conversion on the response signal after the secondary diffusion, and transmits the response signal from the antenna 201 to the base station 100 (FIG. 5).

As described above, in the present embodiment, the response signal is two-dimensionally diffused by the primary diffusion using the ZC series and the secondary diffusion using the Walsh series. That is, in the present embodiment, the response signal is diffused on both the circulation shift axis and the Walsh axis.

Next, the details of the sequence control in the control unit 209 (FIG. 6) will be described.

When the ZC series is used for the primary diffusion of the response signal, as described above, a sufficient difference in the amount of cyclic shift that does not cause intersymbol interference between the ZC series, for example, the difference in the amount of circular shift = 4 Is provided between the ZC series. Therefore, the orthogonality between the different response signals that are first-order diffused using the ZC series with different cyclic shift amounts is not easily broken. On the other hand, as described above, when there is a mobile station that moves at high speed, the orthogonality between the Walsh series used for the secondary diffusion is likely to collapse.

Therefore, in the present embodiment, FIG. 7 is shown in order to absorb the interference component remaining in the response signal even after the backdiffusion in the backdiffusion unit 114 (FIG. 5) by the slight difference in the circulation shift amount of the ZC series. Control the ZC series and Walsh series according to the correspondence. That is, the control unit 209 controls the circulation shift amount of the ZC series used for the primary diffusion in the diffusion unit 214 and the Walsh series used for the secondary diffusion in the diffusion unit 217 according to the correspondence shown in FIG.

In FIG. 7, PUCCH # 1 has ZC # 0 and W # 0, PUCCH # 2 has ZC # 4 and W # 0, PUCCH # 3 has ZC # 8 and W # 0, and PUCCH # 4 has ZC # 1 and W. # 1, PUCCH # 5 to ZC # 5 and W # 1, PUCCH # 6 to ZC # 9 and W # 1, PUCCH # 7 to ZC # 2 and W # 2, PUCCH # 8 to ZC # 6 and W # 2 , PUCCH # 9 with ZC # 10 and W # 2, PUCCH # 10 with ZC # 3 and W # 3, PUCCH # 11 with ZC # 7 and W # 3, PUCCH # 12 with ZC # 11 and W # 3, respectively. It is associated.

Therefore, for example, when the PUCCH number # 1 is input from the determination unit 208, the control unit 209 sets ZC # 0 in the diffusion unit 214 and sets W # 0 in the diffusion unit 217. Further, for example, when the PUCCH number # 2 is input from the determination unit 208, the control unit 209 sets ZC # 4 in the diffusion unit 214 and sets W # 0 in the diffusion unit 217. Further, for example, when the PUCCH number # 4 is input from the determination unit 208, the control unit 209 sets ZC # 1 in the diffusion unit 214 and sets W # 1 in the diffusion unit 217.

Here, in FIG. 7, when W # 1 is used for the secondary diffusion, the ZC series for the primary diffusion: ZC # 1, ZC # 5, ZC # 9 uses W # 0 for the secondary diffusion. ZC series for the primary diffusion of the case: ZC # 0, ZC # 4, ZC # 8 are each cyclically shifted by 1. In addition, the ZC series for primary diffusion when W # 2 is used for secondary diffusion: ZC # 2, ZC # 6, ZC # 10 is the primary diffusion when W # 1 is used for secondary diffusion. ZC series for: ZC # 1, ZC # 5, ZC # 9 are each cyclically shifted by 1. In addition, the ZC series for primary diffusion when W # 3 is used for secondary diffusion: ZC # 3, ZC # 7, ZC # 11 is the primary diffusion when W # 2 is used for secondary diffusion. ZC series for: ZC # 2, ZC # 6, ZC # 10 are each cyclically shifted by 1.

Further, in FIG. 7, the difference in the amount of cyclic shift between the ZC series combined with different Walsh series adjacent to each other is smaller than the difference in the amount of cyclic shift between the ZC series combined with the same Walsh series. For example, the difference in the amount of cyclic shift between ZC # 0 combined with W # 0 and ZC # 1 combined with W # 1 is 1, whereas both are ZC # 0 combined with W # 0. The difference in the amount of cyclic shift between ZC # 4 and ZC # 4 is 4.

Thus, in FIG. 7, the ZC series is cyclically shifted by 1 each time the Walsh series number increases by one. That is, in the present embodiment, the difference in the minimum cyclic shift amount between the ZC series between the Walsh series adjacent to each other is 1. In other words, in FIG. 7, the adjacent Walsh sequences are combined with ZC sequences with different cyclic shift quantities and used for the two-dimensional diffusion of the response signal. Therefore, even if intersymbol interference occurs between the Walsh series due to the collapse of the orthogonality between the Walsh series, the intersymbol interference can be suppressed by spreading in the ZC series. For example, in FIG. 7, the response signal transmitted using PUCCH # 4 is two-dimensionally diffused using ZC # 1 and W # 1, and the response signal transmitted using PUCCH # 7 is ZC # 2 and W. It is two-dimensionally diffused using # 2. Therefore, even if the orthogonality between W # 1 and W # 2 is broken and intersymbol interference occurs between W # 1 and W # 2, the intersymbol interference is caused by ZC # 1 and ZC # 2. It can be suppressed by a slight difference in the amount of cyclic shift between and.

On the other hand, in FIG. 7, as in ZC # 1 and ZC # 2, a ZC series having cyclic shift amounts adjacent to each other, that is, a ZC series having a difference of 1 circular shift amount is used. For this reason, the orthogonality between the ZC series may be broken, and intersymbol interference may occur between the ZC series. However, in FIG. 7, each of the ZCs having a cyclic shift amount difference of 1 is used in combination with different Walsh sequences and for two-dimensional diffusion of the response signal. Therefore, even if intersymbol interference occurs between ZC series due to the collapse of orthogonality between ZC series, the intersymbol interference can be suppressed by diffusion in Walsh series. For example, in FIG. 7, the response signal transmitted using PUCCH # 4 is two-dimensionally diffused using ZC # 1 and W # 1, and the response signal transmitted using PUCCH # 7 is ZC # 2 and W. It is two-dimensionally diffused using # 2. Therefore, even if intersymbol interference occurs between ZC # 1 and ZC # 2, the intersymbol interference can be suppressed by the difference in the sequence between W # 1 and W # 2.

As described above, in the present embodiment, the collapse of orthogonality on the Walsh axis (that is, intersymbol interference between Walsh series) is absorbed on the circular shift axis, and the orthogonality on the circular shift axis is absorbed. It absorbs collapse (that is, intersymbol interference between ZC series) on the Walsh axis. In other words, in the present embodiment, the intersymbol interference between the Walsh series caused by the collapse of the orthogonality between the Walsh series is compensated by the diffusion gain of the ZC series, and the ZC caused by the collapse of the orthogonality between the ZC series is compensated. Intersymbol interference between sequences is compensated by the spreading gain of the Walsh sequence. Therefore, according to the present embodiment, deterioration of the separation characteristic of the response signal code-multiplexed can be minimized.

FIG. 8 is a generalization of the correspondence shown in FIG. That is, FIG. 8 shows a case where a signal is diffused using both a plurality of first series that can be separated from each other by different cyclic shift amounts and a plurality of second series that are orthogonal to each other. That is, according to FIG. 8, when the difference in the amount of cyclic shift between a plurality of first series combined with the same second series is k, a plurality of second series combined with each other are combined. The difference in the amount of cyclic shift between the first series is Δ (Δ &lt;k). That is, in FIG. 8, each time the number of the second series increases by one, the first series is shifted by Δ.

Further, in the present embodiment, as described above, the intersymbol interference between the Walsh series is compensated by the diffusion gain of the ZC series, and the intersymbol interference between the ZC series is compensated by the diffusion gain of the Walsh series. Can be done. Therefore, the difference in the amount of cyclic shift between the ZC series combined with the same Walsh series can be made smaller than that of "4" in FIG. Figure 9 shows the case where this difference is set to "2". In FIG. 7, 12 PUCCHs of PUCCH # 1 to PUCCH # 12 can be used, whereas in FIG. 9, 24 PUCCHs of PUCCH # 1 to PUCCH # 24 can be used. In other words, Figure 7 uses 12 of the 48 code resources, while Figure 9 uses 24 of the 48 code resources. That is, according to the present embodiment, it is possible to increase the utilization efficiency of the limited code resource and maximize the utilization efficiency of the code resource.

Even if the correspondence shown in FIG. 10 is used, the same effect as the case where the correspondence shown in FIG. 9 is used can be obtained.

(Embodiment 2) As shown in FIG. 11, when W # 0 is (1,1,1,1) and W # 1 is (1,-1,1, -1), W # 0 and W # 1 are the first half. The two chips in the above are orthogonal to each other, and the two chips in the latter half are orthogonal to each other. Similarly, if W # 2 is (1,1, -1, -1) and W # 3 is (1, -1, -1,1), then W # 2 and W # 3 are the first two. The chips are orthogonal to each other, and the latter two chips are orthogonal to each other. Therefore, if the change in propagation path state during the two symbol time is small enough, the intersymbol interference between W # 0 and W # 1 and the intersymbol interference between W # 2 and W # 3 will occur. Does not occur. Therefore, a plurality of response signals code-multiplexed by secondary diffusion using W # 0 and # W1 can be separated into two chips in the first half and two chips in the second half. Similarly, a plurality of response signals code-multiplexed by secondary spreading using W # 2 and # W3 can be separated into two chips in the first half and two chips in the second half.

Therefore, in the present embodiment, the control unit 209 uses the ZC series circulation shift amount used for the primary diffusion in the diffusion unit 214 and the Walsh series used for the secondary diffusion in the diffusion unit 217 according to the correspondence shown in FIG. To control. In FIG. 12, the cyclic shift amount of the ZC series combined with W # 0 and the cyclic shift amount of the ZC series combined with W # 1 are the same at 0,2,4,6,10, and are combined with W # 2. The cyclic shift amount of the ZC series and the cyclic shift amount of the ZC series combined with W # 3 are 1,3,5,7,9,11, which are the same.

Here, for example, in order to separate the response signal secondarily diffused by W # 0 when W # 0, W # 1, and W # 2 are used simultaneously for the second diffusion, S in FIG. 1 is used.₀, S₁, S₂, S₃Find the sum of. As a result, the response signal components diffused by W # 1 and W # 2 can be removed from the received signal. However, when the mobile station using W # 1 and the mobile station using W # 2 move at high speed, the difference due to the propagation path fluctuation remains in the response signal after separation as intersymbol interference.

That is, focusing on W # 1, S₀Sign and S₁Since the sign of is different, S₀And S₁The response signal component diffused by W # 1 is removed by the addition of. However, the intersymbol interference of Δ # 1 due to the propagation path fluctuation remains in the response signal after separation. Assuming that the propagation path variation is linear, S₂And S₃Similarly, the intersymbol interference of Δ # 1 remains in the response signal after separation. Therefore, a total of 2 × Δ # 1 intersymbol interference remains in the response signal after separation.

On the other hand, focusing on W # 2, S₀Sign and S₁Since the sign of is the same, S₂And S₃Due to the difference in sign with, the response signal component diffused by W # 2 is removed. In this case, a total of 4 × Δ # 2 intersymbol interference remains in the response signal after separation.

That is, the intersymbol interference between a plurality of response signals code-multiplexed using a plurality of Walsh sequences orthogonal to each other in the first half and orthogonal to each other in the latter two chips becomes small. Therefore, in the present embodiment, different Walsh sequences (W # 0, W # 1) having small intersymbol interference with each other are used in combination with ZC sequences having the same cyclic shift amount, and the intersymbol interference with each other is large. The Walsh series (W # 0, W # 2) is used in combination with the ZC series with different cyclic shift quantities.

As described above, according to the present embodiment, since the response signal is secondarily diffused by using the Walsh sequence which is shorter than the sequence length and is orthogonal to each other in a part of the sequence, the resistance of the mobile station to high-speed movement is further enhanced. be able to.

(Embodiment 3) In the code multiplexing by the first-order diffusion using the ZC series, that is, the code multiplexing on the circular shift axis, as described above, the difference in the amount of the circular shift is sufficient so that the intersymbol interference between the ZC series does not occur. It is provided between ZC series. Therefore, the orthogonality between ZC series is not easily broken. Moreover, even if there is a mobile station that moves at high speed, the orthogonality between the ZC series is not broken. On the other hand, in the code multiplexing by the second-order diffusion using the Walsh series, that is, the code multiplexing on the Walsh axis, the orthogonality between the Walsh series is likely to be broken when there is a mobile station moving at high speed as described above. Therefore, when the response signal is code-multiplexed by secondary diffusion, the average multiplicity on the cyclic shift axis where the orthogonality is hard to be broken is increased, and the average multiplicity on the Walsh axis where the orthogonality is easy to be broken is decreased. That's good. In addition, the multiplicity on the Walsh axis is made uniform among the ZC series so that the multiplicity on the Walsh axis does not become extremely large only in the response signal that is first-order diffused in some ZC series ( It is better to make it uniform). That is, when the response signal is two-dimensionally diffused on both the circular shift axis and the Walsh axis, the multiplicity on the Walsh axis is made uniform among the ZC series while reducing the average multiplicity on the Walsh axis. It is better to make it (uniformly).

Therefore, in the present embodiment, the ZC series and the Walsh series are controlled according to the correspondence shown in FIG. That is, the control unit 209 controls the circulation shift amount of the ZC series used for the primary diffusion in the diffusion unit 214 and the Walsh series used for the secondary diffusion in the diffusion unit 217 according to the correspondence shown in FIG.

Here, in CCE # 1 to CCE # 12, which correspond to PUCCH # 1 to PUCCH # 12 shown in FIG. 13, in the order of CCE # 1, CCE # 2, ..., CCE # 11, CCE # 12. It is assumed that the usage probability P or CCE of the physical resource for the response signal (physical resource for PUCCH) corresponding to the CCE number is lowered. That is, as the CCE number increases, the usage probability P decreases monotonically. Therefore, in the present embodiment, the PUCCH and the ZC series and the Walsh series are associated with each other as shown in FIG.

That is, focusing on the first line (W # 0) and the second line (W # 1) of the Walsh axis in FIG. 13, PUCCH # 1 and PUCCH # 6 are multiplexed, and PUCCH # 2 and PUCCH # 5 are Multiplexed. Therefore, the sum 7 of the PUCCH numbers of PUCCH # 1 and PUCCH # 6 and the sum 7 of the PUCCH numbers of PUCCH # 2 and PUCCH # 5 are equal. That is, on the Walsh axis, the PUCCH with a small number and the PUCCH with a large number are arranged in combination. The same applies to PUCCH # 3, PUCCH # 4, and PUCCH # 7 to PUCCH # 12. The same applies to the third line (W # 2) and the fourth line (W # 3) of the Walsh axis. That is, in FIG. 13, the sum of PUCCH numbers (that is, the sum of CCE numbers) of the Walsh series adjacent to each other is equal among the ZC series adjacent to each other. Therefore, in FIG. 13, the average multiplicity on the Walsh axis becomes almost uniform (almost uniform).

When the difference in the amount of cyclic shift between the ZC series combined with the same Walsh series is "2" (Fig. 9), the degree of multiplicity on the Walsh axis can be made uniform (uniform) between the ZC series. , It is preferable to control the ZC series and the Walsh series according to the correspondence shown in FIG.

In CCE # 1 to CCE # 24 corresponding to PUCCH # 1 to PUCCH # 24 shown in FIG. 14, the CCE numbers are assigned in the order of CCE # 1, CCE # 2, ..., CCE # 23, CCE # 24. It is assumed that the priority of the usage probability P or CCE of the corresponding physical resource for the response signal is lowered. That is, similarly to the above, as the CCE number increases, the usage probability P decreases monotonically.

Focusing on the first line (W # 0) and the third line (W # 2) of the Walsh axis in FIG. 14, PUCCH # 1 and PUCCH # 18 are multiplexed, and PUCCH # 2 and PUCCH # 17 are multiplexed. Axle. Therefore, the sum 19 of the PUCCH numbers of PUCCH # 1 and PUCCH # 18 is equal to the sum 19 of the PUCCH numbers of PUCCH # 2 and PUCCH # 17. Focusing on the second line (W # 1) and the fourth line (W # 3) of the Walsh axis in Fig. 13, PUCCH # 12 and PUCCH # 19 are multiplexed, and PUCCH # 11 and PUCCH # 20 are Multiplexed. Therefore, the sum 31 of the PUCCH numbers of PUCCH # 12 and PUCCH # 19 is equal to the sum 31 of the PUCCH numbers of PUCCH # 11 and PUCCH # 20. That is, on the Walsh axis, as in FIG. 13, the PUCCH having a small number and the PUCCH having a large number are arranged in combination. The same applies to PUCCH # 3 to PUCCH # 10, PUCCH # 13 to PUCCH # 16, and PUCCH # 21 to PUCCH # 24. That is, in FIG. 14, as in FIG. 13, the sum of PUCCH numbers (that is, the sum of CCE numbers) of the Walsh series adjacent to each other is equal among the ZC series adjacent to each other. Therefore, in FIG. 14, as in FIG. 13, the average multiplicity on the Walsh axis becomes almost uniform (almost uniform).

As described above, in the present embodiment, each PUCCH (that is, each CCE) and each sequence used for two-dimensional diffusion are used according to the usage probability P of the physical resource for the response signal corresponding to the CCE number or the priority of the CCE. And associate with. As a result, the average multiplicity on the Walsh axis, that is, the expected value of the PUCCH multiplicity on the Walsh axis becomes almost uniform (nearly uniform). Therefore, according to the present embodiment, the multiplicity on the Walsh axis does not become extremely large only in the response signal first-order diffused in some ZC series, so that the orthogonality between the Walsh series is broken. The impact of such cases can be minimized. Therefore, according to the present embodiment, deterioration of the separation characteristic of the response signal code-multiplexed by the secondary diffusion can be further suppressed.

The embodiments of the present invention have been described above.

In addition, FIG. 7, FIG. 9, FIG. 10, FIG. 12, FIG. 13, and FIG. 14 show the case where four Walsh series W # 0 to W # 3 are used. However, the present invention can be carried out in the same manner as described above even when two, three, or five or more Walsh series are used.

Further, in the above embodiment, the configuration in which the intersymbol interference between the Walsh series is compensated by the diffusion gain of the ZC series is shown. However, the present invention can be applied not only when a completely orthogonal sequence such as a Walsh sequence is used for secondary diffusion, but also when a non-perfect orthogonal sequence such as a PN sequence is used for secondary diffusion. In this case, the intersymbol interference due to the incomplete orthogonality of the PN sequence is compensated by the diffusion gain of the ZC sequence. That is, the present invention can be applied to all wireless communication devices in which sequences that are separable from each other due to different circulation shift amounts are used for primary diffusion, and sequences that are separable from each other due to differences in sequences are used for secondary diffusion. ..

Further, in the above embodiment, a case where a plurality of response signals from a plurality of mobile stations are code-multiplexed has been described. However, the present invention can be carried out in the same manner as described above even when a plurality of reference signals (pilot signals) from a plurality of mobile stations are code-multiplexed. As shown in FIG. 15, the reference signal R of 3 symbols from the ZC series (series length 12).₀, R₁, R₂First, the ZC series is an orthogonal series with a series length of 3 (F).₀, F₁, F₂) Corresponds to each and is IFFT. This IFFT gives a ZC sequence with a sequence length of 12 on the time axis. And the signal after IFFT is an orthogonal series (F)₀, F₁, F₂) To be diffused. That is, one reference signal (ZC series) has three symbols R₀, R₁, R₂Are placed in each. Similarly for other mobile stations, one reference signal (ZC series) has three symbols R.₀, R₁, R₂Are placed in each. However, between different mobile stations, ZC series in which the amount of cyclic shift on the time axis is different from each other, or orthogonal series in which they are different from each other are used. Here, since the series length of the ZC series on the time axis is 12, 12 ZC series having a cyclic shift amount of 0 to 11 generated from the same ZC series can be used. Moreover, since the series length of the orthogonal series is 3, three orthogonal series different from each other can be used. Therefore, in an ideal communication environment, reference signals from a maximum of 36 (12 × 3) mobile stations can be code-multiplexed.

Further, since the PUCCH used in the description of the above embodiment is a channel for feeding back ACK or NACK, it may be referred to as an ACK / NACK channel.

The mobile station is sometimes called UE, the base station is called Node B, and the subcarrier is sometimes called tone. The CP is also sometimes referred to as the Guard Interval (GI).

Moreover, the error detection method is not limited to CRC.

Moreover, the method of performing the conversion between the frequency domain and the time domain is not limited to IFFT and FFT.

Further, in the above-described embodiment, the case where the present invention is applied to a mobile station has been described. However, the present invention can also be applied to a fixed stationary wireless communication terminal device and a wireless communication relay station device that operates in the same manner as a mobile station with a base station. That is, the present invention can be applied to all wireless communication devices.

Further, in the above-described embodiment, the case where the present invention is configured by hardware has been described as an example, but the present invention can also be realized by software.

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

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

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

All disclosures of the specifications, drawings and abstracts contained in the Japanese application of Japanese Patent Application No. 2007-159580 filed June 15, 2007 and Japanese Patent Application No. 2007-161966 filed June 19, 2007 are incorporated herein by reference. To.

The present invention can be applied to mobile communication systems and the like.