JP6612106B2 - Single carrier MIMO transmitter and single carrier MIMO receiver - Google Patents

Description

  The present invention relates to an SC-MIMO (Single Carrier-Multiple-Input Multiple-Output) system that uses a plurality of antennas to wirelessly transmit a large amount of information using a single carrier in a wireless transmission system such as broadcasting or communication. The present invention relates to a transmission apparatus and a reception apparatus, and more particularly to a channel estimation technique for estimating a channel response between a plurality of transmission antennas and one or a plurality of reception antennas.

  Conventionally, in a fixed transmission wireless transmission system such as broadcasting or communication, a single carrier method using one carrier wave has been widely used. The reason for this is that, in the single carrier system, since the PAPR (Peak to Average Power Ratio), which is the ratio between the peak power and the average power of the transmission signal, is generally small, the power amplifier of the transmission apparatus is It can be operated in a high output region, and power efficiency is high.

  On the other hand, the single carrier scheme is susceptible to intersymbol interference due to multipath because the symbol time is short. In general, the single carrier method is not suitable for mobile transmission because channel equalization in the time domain (processing to restore the change in amplitude and phase generated in the propagation path) takes time to converge the equalization coefficient. It was supposed to be.

  However, in recent years, among single carrier schemes, SC-FDE (Single Carrier-Frequency Domain Equalization) schemes that perform channel equalization in the frequency domain have been proposed (for example, Patent Document 1 or non-patent document 1). (See Patent Document 1).

  Since this SC-FDE scheme performs channel estimation and channel equalization in units of blocks, the OFDM (Orthogonal Frequency Division Multiplexing) scheme, which performs channel equalization in the frequency domain, is also used during mobile transmission. It can follow high-speed channel fluctuations. Moreover, since the SC-FDE scheme is provided with a GI (Guard Interval) as in the OFDM scheme, it is possible to prevent inter-block interference in a multipath environment.

  On the other hand, an SC-MIMO technique that separates MIMO signals in the frequency domain by combining the SC-FDE system and a MIMO technique that expands transmission capacity using a plurality of transmission antennas and one or a plurality of reception antennas is proposed. (For example, see Patent Documents 2 and 3). When the SC-FDE scheme is applied to a MIMO system, it is important for the receiving apparatus to accurately estimate the channel response between each transmitting antenna and each receiving antenna from the received signal.

  Patent Document 2 describes a technique in which a block consisting of a pilot symbol sequence is first transmitted, and then a plurality of blocks consisting of a data symbol sequence are transmitted. Specifically, the transmitting apparatus first transmits a block including a pilot symbol sequence to which a CP (Cyclic Prefix) that is a copy of the rear part of the symbol sequence is added. Then, the transmitting apparatus transmits a plurality of blocks composed of data symbol sequences to which CPs are added. In this case, the transmission apparatus assigns a unique pilot code to a pilot symbol for each transmission antenna.

  The receiving apparatus converts the pilot symbol sequence received from the transmitting apparatus into a frequency domain, and performs correlation processing between the converted signal and a reference signal obtained by converting a known pilot symbol sequence into a frequency domain for each transmission antenna. . Then, the receiving apparatus estimates a channel response between each transmitting antenna and each receiving antenna.

  In the technique of Patent Document 2, a different pilot code is assigned to a pilot symbol for each transmission antenna. However, since the correlation between different pilot codes is not completely zero, there is a drawback that an error remains in the estimated channel response.

  Patent Document 3 also generates a pilot SC-FDMA (Single Carrier-Division Multiple Access) symbol that can estimate a channel response, and a plurality of data SC-FDMA symbols and one or more data SC-FDMA symbols. A technique is described in which a signal sequence of one time slot is configured and transmitted using pilot SC-FDMA symbols.

  Specifically, the transmission apparatus converts a data sequence or a pilot sequence into a frequency domain sequence by DFT (Discrete Fourier Transform) processing. Then, the transmitting apparatus maps this to a subband used for transmission, and then returns it to the time domain sequence by IDFT (Inverse Discrete Fourier Transform) processing, and further adds a CP to SC-FDMA. Form a symbol. A plurality of data SC-FDMA symbols and one or more pilot SC-FDMA symbols constitute a signal sequence of one time slot.

  Here, as a technique for transmitting pilot SC-FDMA symbols in MIMO, TDM (Time Division Multiplexing) pilot method, CDM (Code Division Multiplexing) pilot method, distributed or localized pilot method There is.

  The TDM pilot method is a technique of using pilot SC-FDMA symbols for the number of users and transmitting at different timings (see FIG. 5 of Patent Document 3). The transmission apparatus of each user does not transmit pilot SC-FDMA symbols at the same time, but occupies and transmits pilot SC-FDMA symbols in order in time division.

  In the CDM pilot method, a transmitting apparatus assigns orthogonal codes for each user to a plurality of pilot SC-FDMA symbols and transmits them, and a receiving apparatus multiplies and separates multiplexed received pilot SC-FDMA symbols by orthogonal codes. This is a technique (see FIG. 6 of Patent Document 3). The distributed or localized pilot method is a method of assigning pilot sequences to different subbands for each user on the frequency axis (see FIG. 7 of Patent Document 3).

  These methods are premised on application to the SC-FDMA system. After the pilot sequence for each user is separated, the receiving apparatus performs the MMSE (minimum mean square error) method, LS (least square). The method is used to estimate the channel response.

  In the technique of this Patent Document 3, it is assumed that the channel does not fluctuate during one time slot. However, since the signal sequence for one time slot is composed of a plurality of data SC-FDMA symbols and one or more pilot SC-FDMA symbols, the time length of one time slot is relatively long. For this reason, when the channel fluctuates at high speed, there is a drawback that an error remains in the estimated channel response.

  In the technique of Patent Document 3, all SC-FDMA symbols are used, and the channel response is estimated at short intervals on the frequency axis. When a delayed wave exceeding the CP arrives, interference occurs between SC-FDMA symbols, but the time length of the CP is not a value assuming a delayed wave exceeding the time length, but on the frequency axis for estimating the channel response. The interval need not be so short. For this reason, there exists a fault that the estimation capability of a channel response is excessive.

  In general, when a delay time of a delayed wave is assumed to be relatively long, a channel response is obtained by using pilot SC-FDMA symbols having a long time length and arranging pilot signals at short intervals on the frequency axis. Can be estimated with high accuracy. On the other hand, when the delay time of the delay wave is assumed to be relatively short, the time length of the pilot SC-FDMA symbol does not have to be very long, that is, the pilot signal is spaced at a short interval on the frequency axis. There is no need to place in.

  The time length of the CP is set assuming an incoming delayed wave, and it is basically not assumed that a delayed wave exceeding the CP will arrive. Therefore, it is desirable that the interval on the frequency axis of the pilot signal matches the time length of the CP reflecting the delay time of the delay wave, and it is not necessary to make it shorter than necessary. That is, the pilot SC-FDMA symbol need not be set longer than necessary.

  In the technique of Patent Document 3, the interval on the frequency axis of the pilot signal does not correspond to the time length of the CP reflecting the delay time of the delay wave, and is shorter than necessary. That is, the pilot SC-FDMA symbol is set longer than necessary. Since the delay wave is assumed to be within the time length of the CP, the ripple of the frequency characteristic of the channel response is not so fine on the frequency axis. For this reason, pilot signals need not be arranged at such a short interval.

FIG. 11 is a diagram for explaining the relationship between the delay time of the reflected wave (delayed wave) and the ripple. 11A is a diagram showing a multipath model, FIG. 11B is a diagram showing a delay profile, and FIG. 11C is a diagram showing frequency characteristics. As shown in FIG. 11A, there are a direct wave and a reflected wave (delayed wave) from the transmitting antenna to the receiving antenna, and as shown in FIG. 11B, the reflected wave has a GI (guard interval). time as t _g, shall arrive at the receiving antenna on the delay time t _d in the GI.

The ripple of the frequency characteristic in this case has a frequency width of 1 / t _{d as} shown in FIG. That is, the ripple of the frequency characteristic becomes fine when the delay time of the reflected wave is long, and becomes rough when the delay time of the reflected wave is short.

  As described above, the technique of Patent Document 3 is based on the premise that the delay wave is less than or equal to the CP time length, and the ripple of the frequency characteristic of the channel response does not become so fine. There is no need to do. However, pilot SC-FDMA symbols having a relatively long time length are used, and the pilot signal arrangement interval is short. That is, there is no problem even if the pilot SC-FDMA symbol used for estimating the channel response is not so long, and the pilot SC-FDMA symbol that is longer than necessary is used. Has the disadvantage of being excessive.

Japanese Patent No. 5624527 Patent No. 5146920 Japanese Patent No. 4723640

D. Falconer, et al. , “Frequency domain equalization for single-carrier broadband wireless systems,” IEEE Commun. mag. , Vol. 40, pp. 58-66, April 2002.

  As described above, the conventional technique has a problem that the channel response cannot be estimated with high accuracy because the correlation of pilot signals different for each transmission antenna does not become completely zero as in Patent Document 2. Also, as in Patent Document 3, there is a similar problem when high-speed channel fluctuation occurs within one time slot.

  Further, in the prior art, as in Patent Document 3, since the time length of pilot symbols used for estimating the channel response is longer than necessary, there is a problem that the transmission rate is lowered and the transmission efficiency is also lowered. there were.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a single carrier capable of accurately estimating a channel response using pilot symbols having a necessary and sufficient time length in an SC-MIMO scheme. An object of the present invention is to provide a MIMO transmission apparatus and a single carrier MIMO reception apparatus.

In order to solve the above-mentioned problem, the single carrier MIMO transmission apparatus according to claim 1 is provided with the plurality of transmission antennas and the single carrier MIMO reception apparatus via a plurality of transmission antennas by performing MIMO modulation on data to be transmitted. In a single carrier MIMO transmitting apparatus that wirelessly transmits a transmission signal including a pilot signal for estimating a channel response between one or a plurality of receiving antennas to the single carrier MIMO receiving apparatus by a single carrier, the data to be transmitted Between a plurality of transmission systems corresponding to the plurality of transmission antennas, and a predetermined portion after the data with respect to the data of the effective block of a predetermined length in the data distributed by the inter-system distribution unit Is a copy of CP (cyclic prep The pilot signal is set as a UW (unique word) having the same length as the CP, block information for identifying one block from a plurality of consecutive blocks is set, and two consecutive A block configuration unit that generates, for each transmission system, a block including the UW, the block information, the CP, and the data of the effective block, and the block configuration unit is configured for each of the plurality of consecutive blocks. ,-out based on the orthogonal code which is orthogonal in the plurality of transmission systems, sets the UW two consecutive same symbols, and wherein the.

The single carrier MIMO transmission apparatus according to claim 2 performs MIMO modulation on data to be transmitted, and receives a plurality of reception antennas provided in the plurality of transmission antennas and the single carrier MIMO reception apparatus via a plurality of transmission antennas. In a single-carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a pilot signal for estimating a channel response to an antenna to the single-carrier MIMO reception apparatus by a single carrier, the transmission target data is the plurality of transmission targets. An inter-system distribution unit that distributes to a plurality of transmission systems corresponding to a transmission antenna, and a CP that is a copy of a predetermined portion after the data with respect to data of a valid block of a predetermined length in the data distributed by the inter-system distribution unit (Cyclic prefix) is added The pilot signal is set as UW (unique word) having the same length as the CP, block information for identifying one block from a plurality of consecutive blocks is set, two consecutive UW or null data, A block configuration unit that generates a block including block information, the CP, and the data of the effective block for each transmission system, and the block configuration unit includes the plurality of blocks for each of the plurality of consecutive blocks. One of the transmission systems, wherein two consecutive UWs are set for a transmission system that is different from the transmission system in which the UW is set in another block , and among the plurality of transmission systems be other transmission systems of the other blocks to the transmission lines wherein UW is set, two successive said UW progeny Setting the null data Ri, characterized in that.

The single carrier MIMO transmission apparatus according to claim 3 performs MIMO modulation on data to be transmitted, and receives a plurality of reception antennas provided in the plurality of transmission antennas and the single carrier MIMO reception apparatus via a plurality of transmission antennas. In a single-carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a pilot signal for estimating a channel response to an antenna to the single-carrier MIMO reception apparatus by a single carrier, the transmission target data is the plurality of transmission targets. An inter-system distribution unit that distributes to a plurality of transmission systems corresponding to a transmission antenna, and a CP that is a copy of a predetermined portion after the data with respect to data of a valid block of a predetermined length in the data distributed by the inter-system distribution unit (Cyclic prefix) is added Said set pilot signal as the same length of the UW (unique word) and the CP, 2 one of the UW is plural constituted preamble continuous by a single preamble, and the CP and the by a single block A block configuration unit that generates, for each transmission system, a plurality of blocks in which valid block data is configured , wherein the block configuration unit is orthogonal in the plurality of transmission systems for each of a plurality of consecutive preambles. -out based on the orthogonal codes, setting said UW two successive same symbols, and wherein the.

The single carrier MIMO transmission apparatus according to claim 4 performs MIMO modulation on data to be transmitted, and receives a single or a plurality of receptions provided in the plurality of transmission antennas and the single carrier MIMO reception apparatus via a plurality of transmission antennas. In a single-carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a pilot signal for estimating a channel response to an antenna to the single-carrier MIMO reception apparatus by a single carrier, the transmission target data is the plurality of transmission targets. An inter-system distribution unit that distributes to a plurality of transmission systems corresponding to a transmission antenna, and a CP that is a copy of a predetermined portion after the data with respect to data of a valid block of a predetermined length in the data distributed by the inter-system distribution unit (Cyclic prefix) is added It said set pilot signal as the same length of the UW (unique word) and the CP, 2 one of the UW or null data of the plurality configured preamble continuous by a single preamble, and the CP by a single block and the valid data block in the plurality constructed blocks, and a block generator for generating for each of the transmission system, the block unit for each of the plurality of preamble continue communicating, transmitting the plurality a single transmission line of the system, for different transmission lines and transmission lines said UW by another preamble is set, to set the two consecutive said UW, of the plurality of transmission systems For another transmission system, in which the UW is set in the other preamble, two consecutive UWs Instead, the null data is set.

  Furthermore, the single carrier MIMO receiving apparatus according to claim 5 receives the transmission signal transmitted via the plurality of transmitting antennas included in the single carrier MIMO transmitting apparatus according to claim 1 via the single or plural receiving antennas. By performing MIMO demodulation on a received signal in which a block composed of two consecutive UWs, block information, CP, and effective block data is multiplexed, between the plurality of transmitting antennas and the one or more receiving antennas In a single carrier MIMO receiver that estimates a channel response, separates signals transmitted from the plurality of transmission antennas, and restores the original transmission target data, the reception is performed by a synchronization process for obtaining a correlation with respect to the received signal. Detecting the beginning of a block of signals, detecting the block information from the block of received signals, The block synchronization unit for identifying the block of the received signal based on the block information and the block synchronization unit identify the block in which UWs set based on orthogonal codes for all of a plurality of transmission systems are multiplexed. Then, FFT (Fast Fourier Transform) is performed using a reception UW subsequent to the consecutive reception UWs included in the block, and the channel response is estimated based on the result of the FFT and a preset reference signal And a channel estimation unit.

  A single carrier MIMO receiver according to claim 6 receives a transmission signal transmitted via a plurality of transmission antennas included in the single carrier MIMO transmitter according to claim 2 via a single or a plurality of reception antennas. By performing MIMO demodulation on a received signal in which a block consisting of two consecutive UW or null data, block information, CP and effective block data is multiplexed, the plurality of transmission antennas and the one or more reception antennas In a single-carrier MIMO receiver that estimates the channel response between, separates the signals transmitted from the plurality of transmission antennas, and restores the original transmission target data, by a synchronization process for obtaining a correlation with the received signal, Detecting the beginning of the block of the received signal, the block from the received signal block A block synchronizer that detects the information and identifies the block of the received signal based on the block information, and a UW for one transmission system of a plurality of transmission systems, and another transmission system by the block synchronizer The block in which the null data is multiplexed is identified, and FFT (Fast Fourier Transform) is performed using the received UW subsequent to the consecutive received UWs included in the block, and the FFT result is set in advance. And a channel estimation unit for estimating the channel response based on the reference signal.

  The single carrier MIMO receiving apparatus according to claim 7 receives a transmission signal transmitted via a plurality of transmitting antennas included in the single carrier MIMO transmitting apparatus according to claim 3 via one or a plurality of receiving antennas. By performing MIMO demodulation on a reception signal in which a preamble consisting of two consecutive UWs and a reception signal in which a block consisting of CP and effective block data is multiplexed, the plurality of transmission antennas and the singular or In a single-carrier MIMO receiving apparatus that estimates channel responses with a plurality of receiving antennas, separates signals transmitted from the plurality of transmitting antennas, and restores the original transmission target data, the correlation with the received signals Synchronization processing to obtain the leading end of the preamble of the received signal and the block of the received signal The block synchronization unit for detecting the head and the block synchronization unit detect the preamble in which UWs set based on orthogonal codes for all of a plurality of transmission systems are detected, and consecutive reception UWs included in the preamble A channel estimator that performs FFT (Fast Fourier Transform) using the received UW behind the signal and estimates the channel response based on the FFT result and a preset reference signal. It is characterized by.

  Further, the single carrier MIMO receiving apparatus according to claim 8 receives the transmission signals transmitted via the plurality of transmitting antennas of the single carrier MIMO transmitting apparatus according to claim 4, via one or a plurality of receiving antennas. By performing MIMO demodulation on a reception signal in which a preamble consisting of two consecutive UW or null data is multiplexed and a reception signal in which a block consisting of CP and effective block data is multiplexed, the plurality of transmission antennas and the singular or In a single-carrier MIMO receiving apparatus that estimates channel responses with a plurality of receiving antennas, separates signals transmitted from the plurality of transmitting antennas, and restores the original transmission target data, correlates with the received signals. Synchronization processing to obtain the leading end of the preamble of the received signal and the received signal The block synchronization unit for detecting the head of the lock and the block synchronization unit detect the preamble in which the UW for one transmission system of a plurality of transmission systems and the null data for the other transmission system are multiplexed. Then, FFT (Fast Fourier Transform) is performed using the received UWs behind the consecutive received UWs included in the preamble, and the channel response is estimated based on the FFT result and a preset reference signal And a channel estimation unit.

  As described above, according to the present invention, in the SC-MIMO scheme, it is possible to estimate a channel response with high accuracy using a pilot symbol having a necessary and sufficient time length.

It is a block diagram which shows the example of a whole structure of the SC-MIMO system containing the transmitter and receiver by embodiment of this invention. It is a figure explaining a 1st signal format. It is a figure explaining a 2nd signal format. It is a figure explaining a 3rd signal format. It is a figure explaining a 4th signal format. It is a block diagram which shows the structural example of the transmitter by embodiment of this invention. It is a block diagram which shows the structural example of the receiver by embodiment of this invention. It is a figure explaining block information. It is a figure explaining the 1st signal format in case the number of transmitting antennas is 4 (n = 4). It is a figure explaining the 2nd signal format in case the number of transmitting antennas is 4 (n = 4). It is a figure explaining the relationship between the delay time of a reflected wave (delayed wave) and a ripple.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
[SC-MIMO system]
First, the SC-MIMO system will be described. FIG. 1 is a block diagram illustrating an overall configuration example of an SC-MIMO system including a transmission device and a reception device according to an embodiment of the present invention. This SC-MIMO system is an example of a 2 × 2 SC-MIMO system with two transmissions and two receptions, and includes a transmission device (single carrier MIMO transmission device) 1 and a reception device (single carrier MIMO reception device) 2. One-to-one communication from the transmission device 1 to the reception device 2 is performed.

  The transmission apparatus 1 includes an SC-MIMO modulation unit 10, transmission high-frequency units 30-1 and 30-2, and two transmission antennas 40-1 and 40-2. The receiving device 2 includes two receiving antennas 50-1 and 50-2, receiving high-frequency units 60-1 and 60-2, and an SC-MIMO demodulating unit 70.

Transmission signal x ₁ a signal transmitted from the transmission antenna 40-1 of the transmitting device 1, a signal to be transmitted as a transmission signal x ₂ from the transmit antennas 40-2. In the transmission path between the transmission apparatus 1 and the reception apparatus 2, the channel response (impulse response) between the transmission antenna 40-1 and the reception antenna 50-1 is h ₁₁ , and the transmission antenna 40-2 and the reception antenna 50- 1 h ₁₂ the channel response between the channel response between the channel response between the transmission antenna 40-1 and the receiving antenna 50-2 h _21, the transmission antenna 40-2 and the receiving antenna 50-2 h ₂₂

The signal received through the receiving antenna 50-1 of the transmission path and the reception apparatus 2 from the transmitting device 1 and the reception signal y _1, received via the receiving antenna 50-2 of the transmission path and the reception device 2 from the transmitter 1 the signal and the reception signal y _2.

  The SC-MIMO modulation unit 10 of the transmission apparatus 1 receives information to be transmitted, performs SC-MIMO modulation processing, and distributes the modulated signal to two transmission systems. Then, SC-MIMO modulation section 10 outputs a modulated signal including a pilot signal in the first transmission system to transmission high frequency section 30-1. Further, SC-MIMO modulation section 10 outputs a modulated signal including a pilot signal in the second transmission system to transmission high frequency section 30-2. Details of the SC-MIMO modulation unit 10 will be described later.

The transmission high-frequency unit 30-1 receives the first modulated signal from the SC-MIMO modulation unit 10, and converts the IF (Intermediate Frequency) signal of the modulated signal into an RF (Radio Frequency) signal. . The transmission RF section 30-1, as a transmission signal x ₁ of the RF signal of a predetermined power, and transmits via a transmit antenna 40-1.

Transmission RF unit 30-2 receives the second modulated signal from the SC-MIMO modulation unit 10, the IF signal of the modulation signal is frequency-converted into an RF signal, as a transmission signal x ₂ a RF signal of a predetermined power, transmission Transmit via antenna 40-2.

The transmission signal x ₁ transmitted from the transmission antenna 40-1 and the transmission signal x ₂ transmitted from the transmission antenna 40-2 are multiplexed in the space of the transmission path.

Receiving radio-frequency unit 60-1 of the receiving apparatus 2, the multiplexed signal of the transmission signal x ₁ and the transmission signal x ₂ transmitted from the transmitting apparatus 1, received via the receiving antenna 50-1, the received signal is a multiplexed signal y ₁ is amplified, and the RF signal of the received signal y ₁ is frequency-converted into an IF signal. Then, reception high frequency section 60-1 outputs the IF signal to SC-MIMO demodulation section 70 as the reception IF signal of the first reception system.

Receiving radio-frequency unit 60-2 of the receiving apparatus 2, the multiplexed signal of the transmission signal x ₁ and the transmission signal x ₂ transmitted from the transmitting apparatus 1, received via the receiving antenna 50-2, the received signal is a multiplexed signal amplifying the y _2, frequency-converts the RF signal of the received signal y ₂ into an IF signal. Then, reception high frequency section 60-2 outputs the IF signal to SC-MIMO demodulation section 70 as the reception IF signal of the second reception system.

The SC-MIMO demodulator 70 receives the reception IF signal of the first reception system from the reception high-frequency unit 60-1 and receives the reception IF signal of the second reception system from the reception high-frequency unit 60-2. Then, SC-MIMO demodulation section 70 performs SC-MIMO demodulation processing to estimate channel responses h ₁₁ , h ₁₂ , h ₂₁ , and h ₂₂ based on the received pilot signals, and restores the original information. Output. Details of the SC-MIMO demodulator 70 will be described later.

[Channel estimation method]
Next, a channel estimation method in the SC-MIMO system shown in FIG. 1 will be described. Hereinafter, four types of channel estimation methods will be described. The first channel estimation method and the second channel estimation method are applied when the channel fluctuation is relatively fast, and the third channel estimation method and the fourth channel estimation method are used when the channel fluctuation is relatively slow. There is application.

(First channel estimation method)
FIG. 2 is a diagram illustrating a signal format (first signal format) of the first channel estimation method. Transmission signal x ₁ shown in FIG. 2 shows a signal transmitted from the transmission RF unit 30-1 of the transmitting apparatus 1 shown in FIG. 1, the transmission signal x ₂ is transmitted from the transmission RF unit 30-2 Signal. The same applies to FIGS. 3 to 5 described later.

The transmission signals x ₁ and x ₂ in the first channel estimation method are configured in units of two blocks. Each block of the transmission signals x ₁ and x ₂ is composed of two consecutive unique words (UW), block information, CP, and valid block data. The data of the effective block indicates data corresponding to information to be transmitted in the block.

  UW is pilot signal data for estimating a channel response, and a Chu sequence or a Frank-Zadof sequence having a constant amplitude and excellent autocorrelation characteristics is used. CP is a copy of the rear part of the data of the effective block. The CP length (time length) is a predetermined length between 1/8 and 1/32 (for example, 1/8 to 1/32) of the effective block data length (period during which data is FFTed). ) Is used. The length of UW is the same as CP. That is, the length of UW is 1/8 of the effective block data length (for example, a predetermined length from 1/8 to 1/32). The same applies to the second to fourth channel estimation methods.

  The block information is information for identifying the first block and the second block before the MIMO signal separation is performed by the SC-MIMO demodulator 70 of the reception device 2. The SC-MIMO modulation unit 10 of the transmission device 1 and the SC-MIMO demodulation unit 70 of the reception device 2 shown in FIG. 1 perform processing in units of blocks. The same applies to the second channel estimation method.

The SC-MIMO modulation unit 10 of the transmission device ₁ sets two consecutive UWs in the same phase for the first blocks of the transmission signals x ₁ and x ₂ . Then, SC-MIMO modulation section 10 sets two consecutive UWs in phase with the UW of the first block for the second block of transmission signal x ₁ . Also, the SC-MIMO modulation unit 10 sets two consecutive UWs in the second block of the transmission signal x ₂ in opposite phases to the UW of the first block (the UW of the second block of the transmission signal x ₁ is set). Invert and set to reverse phase).

  That is, SC-MIMO modulation section 10 sets the UW of each transmission system using orthogonal codes that are orthogonal in the two transmission systems. Specifically, the SC-MIMO modulation unit 10 reflects the orthogonal code for each transmission system by multiplying two consecutive UWs of each transmission system by orthogonal codes of the length of the number of transmission systems. Set two consecutive UWs. Thereby, the block for the length of the orthogonal code containing two continuous UW is produced | generated for every transmission system | strain. An orthogonal code having a length exceeding the number of transmission systems may be used. The same applies to a third channel estimation method described later.

Thus, the transmission signals x ₁ and x ₂ are the same in the UW of the transmission signal x ₁ between the first block and the second block, and the UW of the transmission signal x ₂ is inverted between the first block and the second block. Sent in state. That is, the transmission signals x ₁ and x ₂ are transmitted in a state where UWs that are continuous over two blocks are orthogonal. That is, for simplicity of explanation, if UW = 1, as shown in FIG. 2, the orthogonal code has a length of 2, and the UWs in which the transmission signal x ₁ is continuous (first block, second block). ) = (1, 1), and the UWs of the transmission signal x ₂ are (first block, second block) = (1, −1). In this case, since (1, 1) · (1, −1) = 0, the transmission signals x ₁ and x ₂ are transmitted in an orthogonal state.

The SC-MIMO demodulator 70 of the receiving device 2 adds (adds) the reception UW of the first block (the UW of the first block in the multiplexed signal of the received transmission signals x ₁ and x ₂ ) and the reception UW of the second block. The result is subjected to FFT (Fast Fourier Transform). Then, the SC-MIMO demodulator 70 performs transmission based on the FFT result of the reception UW and the result (reference signal) obtained by performing FFT on the transmission UW (UW of transmission signals x ₁ and x ₂ , UW set in advance). Channel responses h ₁₁ and h ₂₁ for the signal x ₁ are estimated.

Similarly, the SC-MIMO demodulator 70 performs FFT on the difference (subtraction result) between the reception UW of the first block and the reception UW of the second block, and based on the FFT result of the reception UW and the reference signal of the transmission UW Thus, channel responses h ₁₂ and h ₂₂ for the transmission signal x ₂ are estimated.

(Second channel estimation method)
FIG. 3 is a diagram for explaining a signal format (second signal format) of the second channel estimation method. The transmission signals x ₁ and x ₂ in the second channel estimation method are configured in units of two blocks. Each block of the transmission signals x ₁ and x ₂ includes two consecutive unique word (UW) or null data, block information, CP, and valid block data.

SC-MIMO modulation unit 10 of the transmitting apparatus 1, the first block of the transmitted signal x _1, set the two consecutive UW, for the first block transmission signal x _2, null data into the position of two successive UW Set. Then, the SC-MIMO modulation unit 10 sets null data at two consecutive UW positions for the second block of the transmission signal x ₁ , and two continuous UWs for the second block of the transmission signal x ₂ , The same phase as the UW of the first block of the transmission signal x ₁ is set. As a result, the transmission signals x ₁ and x ₂ are sequentially transmitted in a time-division state with the UW of the transmission signal x _{1 and} the UW of the transmission signal x ₂ .

The SC-MIMO demodulator 70 of the reception apparatus 2 performs FFT on the reception UW of the first block, and based on the FFT result of the reception UW and the reference signal of the transmission UW, channel responses h ₁₁ and h for the transmission signal x ₁ Estimate ₂₁ .

Similarly, the SC-MIMO demodulator 70 performs FFT on the reception UW of the second block, and based on the FFT result of the reception UW and the reference signal of the transmission UW, channel responses h ₁₂ and h ₂₂ for the transmission signal x ₂ . Is estimated.

(Third channel estimation method)
FIG. 4 is a diagram for explaining a signal format (third signal format) of the third channel estimation method. The transmission signals x ₁ and x ₂ in the third channel estimation method are configured with two preambles and a plurality of blocks as units. Each preamble of the transmission signals x ₁ and x ₂ is composed of two consecutive UWs, and each block of the transmission signals x ₁ and x ₂ is composed of CP and effective block data.

The SC-MIMO modulation unit 10 of the transmission apparatus 1 sets two consecutive UWs in the same phase for the preamble 1 of the transmission signals x ₁ and x ₂ . Then, SC-MIMO modulation section 10 sets two consecutive UWs in the same phase as UW of preamble ₁ for preamble 2 of transmission signal x ₁ . Also, the SC-MIMO modulation unit 10 sets two consecutive UWs for the preamble ₂ of the transmission signal x ₂ in opposite phases to the UW of the preamble 1 (invert the UW of the preamble 2 of the transmission signal x ₁ Set to opposite phase).

As a result, the transmission signals x ₁ and x ₂ are transmitted in a state where the UW of the transmission signal x ₁ is the same between the preamble 1 and the preamble 2 and the UW of the transmission signal x ₂ is inverted between the preamble 1 and the preamble 2. The That is, the transmission signals x ₁ and x ₂ are transmitted in a state where UWs that are continuous over two preambles are orthogonal. That is, for the sake of simplicity, if UW = 1, the orthogonal code has a length of 2, and (preamble 1, preamble 2) = (1, 1) for UWs in which the transmission signal x ₁ is continuous. In this case, (preamble 1 and preamble 2) = (1, −1) for UWs in which the transmission signal x ₂ is continuous. In this case, since (1, 1) · (1, −1) = 0, the transmission signals x ₁ and x ₂ are transmitted in an orthogonal state.

The SC-MIMO demodulator 70 of the receiving apparatus 2 calculates the sum (addition result) of the received UW of preamble 1 (the UW of preamble 1 in the multiplexed signal of the received transmission signals x ₁ and x ₂ ) and the received UW of preamble 2. The FFT is performed. Then, the SC-MIMO demodulator 70 estimates channel responses h ₁₁ and h ₂₁ for the transmission signal x ₁ based on the FFT result of the reception UW and the reference signal of the transmission UW.

Similarly, the SC-MIMO demodulation unit 70 performs FFT on the difference (subtraction result) between the reception UW of the preamble 1 and the reception UW of the preamble 2, and based on the FFT result of the reception UW and the reference signal of the transmission UW, Channel responses h ₁₂ and h ₂₂ for the transmission signal x ₂ are estimated.

(Fourth channel estimation method)
FIG. 5 is a diagram for explaining a signal format (fourth signal format) of the fourth channel estimation method. The transmission signals x ₁ and x ₂ in the fourth channel estimation method are configured in units of two preambles and a plurality of blocks. Each preamble of the transmission signals x ₁ and x ₂ is composed of two continuous UW or null data, and each block of the transmission signals x ₁ and x ₂ is composed of CP and valid block data.

SC-MIMO modulation unit 10 of the transmitting apparatus 1, for a preamble first transmission signal x _1, set the two consecutive UW, the preamble first transmission signal x _2, sets the null data on the position of the two consecutive UW To do. Then, SC-MIMO modulation section 10 sets null data at two consecutive UW positions for preamble 2 of transmission signal x ₁ . Further, SC-MIMO modulation section 10 sets two consecutive UWs for preamble 2 of transmission signal x ₂ in phase with UW of preamble 1 of transmission signal x ₁ . As a result, the transmission signals x ₁ and x ₂ are sequentially transmitted in a time-division state with the UW of the transmission signal x _{1 and} the UW of the transmission signal x ₂ .

The SC-MIMO demodulator 70 of the receiving apparatus 2 performs FFT on the reception UW of the preamble 1 and, based on the FFT result of the reception UW and the reference signal of the transmission UW, channel responses h ₁₁ and h ₂₁ for the transmission signal x ₁ . Is estimated.

Similarly, the SC-MIMO demodulator 70 performs FFT on the received UW of the preamble 2 and obtains channel responses h ₁₂ and h ₂₂ for the transmitted signal x ₂ based on the FFT result of the received UW and the reference signal of the transmitted UW. presume.

[Principle of channel estimation and signal separation]
Next, the principle of channel estimation and signal separation in the SC-MIMO system shown in FIG. 1 will be described. As described above, the transmission signals x ₁ and x ₂ , the reception signals y ₁ and y ₂ , and the channel responses h ₁₁ , h ₁₂ , h ₂₁ , and h _{22 are} assumed. Also, let n ₁ and n ₂ be noise added by the receiving device 2.

ここで、ｋは遅延時間を示し、チャネル応答ｈ₁₁〜ｈ₂₂は、２つのブロックの時間において変化せず、遅延波はＵＷ期間内に収まっているものと仮定する。 Each of the received signals y ₁ and y ₂ can be expressed by a convolution integral formula as follows.

Here, k represents a delay time, and it is assumed that the channel responses h _{11 to} h ₂₂ do not change in the time of the two blocks, and the delay wave is within the UW period.

The variable in the time domain and the variable in the frequency domain after FFT (Fourier transform) are defined as having the following relationship.

When the equations (1) and (2) are Fourier transformed, the following equation is obtained.

When this is expressed in a matrix, the propagation equation of 2 × 2 MIMO is obtained as follows.

In the first channel estimation method described above, the UW of the transmission signal x ₁ is the same between the two blocks, and the UW of the transmission signal x ₂ is inverted between the two blocks. In the third channel estimation method described above, the UW of the transmission signal x ₁ is the same between the two preambles, and the UW of the transmission signal x ₂ is inverted between the two preambles. When the block length or preamble length is t _B , the following equation is satisfied in the UW period.

Using the relationship of the equation (6), the signal of the UW part of the adjacent block or preamble of the equation (1) is expressed by the following equation.

The sum and difference of said Formula (7) and said Formula (8) are represented by following Formula.

とする。

The FFT (Fourier transform) of the formula (9) and the formula (10) is expressed by the following formula. However,

And

は既知であり、ノイズ項を無視することにより、後述する式（１３）及び式（１４）から、

を推定することができる。また、前記式（２）について同様の処理を行うことにより、

を推定することができる。

In the UW period,

Is known, and by ignoring the noise term, from equations (13) and (14) described below,

Can be estimated. In addition, by performing the same processing for the formula (2),

Can be estimated.

を求めることができる。そして、さらにＩＦＦＴ（逆フーリエ変換）により、

を求めることができる。 Then, using the ZF algorithm or the MMSE algorithm, solving the equation (5) to perform MIMO signal separation,

Can be requested. And further by IFFT (Inverse Fourier Transform)

Can be requested.

In the second channel estimation method described above, UWs of the transmission signals x ₁ and x ₂ are alternately transmitted in two blocks of the first block and the second block, and in the fourth channel estimation method described above, the transmission signal x ₁ and x ₂ UWs are transmitted alternately in two preambles, preamble 1 and preamble 2.

The following formula is satisfied in the UW period.

とする。

When the equation (15) and the equation (16) are FTT (Fourier transform), the following equation is obtained. However,

And

は既知であり、ノイズ項を無視することにより、後述する式（１９）及び式（２０）から、

を推定することができる。
同様に、

から、

を推定することができる。

In the UW period,

Is known, and by ignoring the noise term, from Equation (19) and Equation (20) described below,

Can be estimated.
Similarly,

From

Can be estimated.

を求めることができる。そして、さらにＩＦＦＴ（逆フーリエ変換）により、

を求めることができる。 Then, using the ZF algorithm or the MMSE algorithm, solving the equation (5) to perform MIMO signal separation,

Can be requested. And further by IFFT (Inverse Fourier Transform)

Can be requested.

Thus, in the SC-MIMO system shown in FIG. 1, the channel response can be estimated, and the multiplexed signal can be separated into the original transmission signals x ₁ and x ₂ .

[Transmitter]
Next, the transmitter 1 shown in FIG. 1 will be described in detail. FIG. 6 is a block diagram illustrating a configuration example of the transmission device 1 according to the embodiment of the present invention. As shown in FIG. 1, the transmission device 1 includes an SC-MIMO modulation unit 10, transmission high-frequency units 30-1 and 30-2, and two transmission antennas 40-1 and 40-2.

  The SC-MIMO modulation unit 10 includes a data frame synchronization unit 11, an energy spreading unit 12, an outer code coding unit 13, an outer interleaving unit 14, an inner code coding unit 15, an inter-system sorting unit 16, and an inner interleaving unit 17-1. , 17-2, mapping units 18-1, 18-2, SC block configuration units 19-1, 19-2, band limiting filters 20-1, 20-2, digital orthogonal modulation units 21-1, 21-2, and DA converters 22-1 and 22-2 are provided.

A transmission branch, which is a first transmission system, is configured by the components from the inner interleaving unit 17-1 to the DA conversion unit 22-1 provided in the SC-MIMO modulation unit 10, the transmission high-frequency unit 30-1, and the transmission antenna 40-1. # 1 is configured. The transmission signal x ₁ (t) is transmitted via the transmission antenna 40-1 of the transmission branch # 1.

A transmission branch, which is a second transmission system, is configured by the components from the inner interleaving unit 17-2 to the DA conversion unit 22-2, the transmission high-frequency unit 30-2, and the transmission antenna 40-2 provided in the SC-MIMO modulation unit 10. # 2 is configured. The transmission signal x ₂ (t) is transmitted via the transmission antenna 40-2 of the transmission branch # 2.

  The transmission high-frequency units 30-1 and 30-2 and the transmission antennas 40-1 and 40-2 have already been described with reference to FIG.

  The data frame synchronization unit 11 of the SC-MIMO modulation unit 10 inputs information such as a TS packet of a video signal and performs a frame configuration on the information data packet. Then, the data frame synchronization unit 11 outputs the data packet after the frame configuration to the energy spreading unit 12.

  The energy spreading unit 12 receives the data packet after the frame configuration from the data frame synchronization unit 11, and the 1 and 0 bits that constitute the data packet so that the 1 and 0 bits that constitute the data packet are not consecutive. Performs an exclusive OR operation with a pseudo-random code. Then, the energy spreading unit 12 outputs the signal after energy spreading to the outer code encoding unit 13.

  The outer code encoding unit 13 receives the signal after energy diffusion from the energy spreading unit 12 and performs outer code encoding by error correction encoding processing using a Reed-Solomon code or the like. Then, outer code encoding section 13 outputs the signal after outer code encoding to outer interleaving section 14.

  The outer interleaving unit 14 receives the signal after outer code encoding from the outer code encoding unit 13 and shuffles the data of the input signal so that transmission errors are not concentrated in one place and the error correction capability is deteriorated. To perform external interleaving. Then, the outer interleaving unit 14 outputs the signal after the outer interleaving to the inner code encoding unit 15.

  The inner code encoding unit 15 receives the signal after outer interleaving from the outer interleaving unit 14 and performs inner code encoding by error correction encoding processing using a convolutional code or the like. Then, the inner code encoding unit 15 outputs the signal after the inner code encoding to the inter-system distribution unit 16.

  The inter-system distribution unit 16 receives the signal after the inner code encoding from the inner code encoding unit 15 and distributes the data of the input signal to distribute to the two transmission systems of the transmission branches # 1 and # 2. . The inter-system distribution unit 16 outputs the signal distributed for the transmission branch # 1 to the inner interleaving unit 17-1, and outputs the signal distributed for the transmission branch # 2 to the inner interleaving unit 17-2.

  The inner interleaving unit 17-1 of the transmission branch # 1 inputs a signal from the inter-system distributing unit 16, and performs inner interleaving by shuffling data so that transmission symbol errors are not concentrated in the bit sequence or the time sequence. Then, inner interleaving section 17-1 outputs the signal after the inner interleaving to mapping section 18-1. The inner interleaving unit 17-2 of the transmission branch # 2 performs the same process as the inner interleaving unit 17-1.

  The mapping unit 18-1 receives the signal after the inner interleaving from the inner interleaving unit 17-1, and performs mapping on the input signal data using signal point arrangement such as QPSK and 16APSK. Then, mapping section 18-1 outputs the mapped signal to SC block configuration section 19-1. The mapping unit 18-2 of the transmission branch # 2 performs the same process as the mapping unit 18-1.

The SC block configuration unit 19-1 receives the mapped signal from the mapping unit 18-1, and copies the predetermined part after the data symbol (effective block data) and inserts it in the previous part, thereby enabling A CP is added to the block data. Then, the SC block configuration unit 19-1 further inserts a predetermined UW or the like, and any _one of the first to fourth signal formats in the transmission signal x1 shown in FIGS. A signal in a signal format (a signal in a predetermined format) is generated. The SC block configuration unit 19-1 outputs a signal in a predetermined format to the band limiting filter 20-1 as a signal after the SC block configuration.

SC block generator 19-2 transmitting branch # 2, in response to a signal of a predetermined format that SC block generator 19-1 generates, first the first through the transmission signal x ₂ shown in FIGS. 2 to 5 A signal having any one of the four signal formats is generated.

(When using the first signal format / first channel estimation method)
A case where the first signal format shown in FIG. 2 is used will be described. SC block generator 19-1 generates a first signal of the signal format in the transmission signals x ₁ shown in FIG. 2, SC block generator 19-2 first in the transmission signal x ₂ shown in FIG. 2 A signal having a signal format of 1 is generated.

Specifically, when the first block of the transmission signal x ₁ is generated, the SC block configuration unit 19-1 adds a CP before the data symbol (effective block data), and the SC block configuration unit 19- 2 consecutive UWs having the same phase as 2 are set. Further, the SC block configuration unit 19-1 sets predetermined block information. Then, the SC block configuration unit 19-1 generates a first block in the order of two consecutive UWs, block information, CP, and valid block data.

  Here, the predetermined block information is information that makes it possible to identify the first block and the second block before MIMO signal separation is performed in the receiving apparatus 2 as described above. The same applies to the following.

When the first block of the transmission signal x ₂ is generated, the SC block configuration unit 19-2 adds a CP before the data symbol (effective block data), and has the same phase as the SC block configuration unit 19-1. Set two consecutive UWs. The SC block configuration unit 19-2 sets predetermined block information. Then, the SC block configuration unit 19-2 generates a first block in the order of two consecutive UWs, block information, CP, and valid block data.

When the second block of the transmission signal x ₁ is generated, the SC block configuration unit 19-1 adds a CP in front of the data symbol (effective block data), and two consecutive blocks having the same phase as the first block Set UW. Further, the SC block configuration unit 19-1 sets predetermined block information. Then, the SC block configuration unit 19-1 generates a second block in the order of two consecutive UWs, block information, CP, and valid block data.

When the second block of the transmission signal x ₂ is generated, the SC block configuration unit 19-2 adds a CP before the data symbol (effective block data) and is set by the SC block configuration unit 19-1. By inverting the polarity of UW (UW of the second block), two consecutive UWs having opposite phases to this are set. The SC block configuration unit 19-2 sets predetermined block information. Then, the SC block configuration unit 19-2 generates a second block in the order of two consecutive UWs, block information, CP, and valid block data.

Thus, UW of the transmission signal x ₁ generated by the SC block generator 19-1 is the same in the first and second blocks. Further, the UW of the transmission signal x ₂ generated by the SC block configuration unit 19-2 is inverted between the first block and the second block.

FIG. 8 is a diagram illustrating block information set by the SC block configuration units 19-1 and 19-2. As the predetermined block information, for example, differential data subjected to DBPSK modulation is used as shown in FIG. Specifically, the SC block configuration units 19-1 and 19-2 perform DBPSK modulation on predetermined data, and generate the same differential data in the transmission signals x ₁ and x ₂ . SC block generator 19-1, when generating the first block of the transmitted signal x _1, sets the differential data of the preceding first block and the same phase in the block information. SC block generator 19-2 when generating the first block of the transmission signal x _2, sets the differential data of the preceding first block and the same phase in the block information.

SC block generator 19-1, when generating the second block of the transmission signal x _1, sets the differential data of the previous second block and the opposite phase to the block information. SC block generator 19-2 when generating a second block of transmission signal x _2, sets the differential data of the previous second block and the opposite phase to the block information.

  That is, in the first block, differential data having the same phase as the previous first block is set in the block information by the SC block configuration units 19-1 and 19-2 each time. In the second block, the SC block configuration units 19-1 and 19-2 set differential data in the opposite phase to the previous second block in the block information every time.

(When using the second signal format / second channel estimation method)
A case where the second signal format shown in FIG. 3 is used will be described. SC block generator 19-1 generates a signal of a second signal form in the transmission signals x ₁ shown in FIG. 3, SC block generator 19-2 first in the transmission signal x ₂ shown in FIG. 3 A signal having a signal format of 2 is generated.

Specifically, when the first block of the transmission signal x ₁ is generated, the SC block configuration unit 19-1 adds a CP before the data symbol (effective block data), and adds two consecutive UWs. Set and set block information in phase with the previous first block. Then, the SC block configuration unit 19-1 generates a first block in the order of two consecutive UWs, block information, CP, and valid block data.

When the first block of the transmission signal x ₂ is generated, the SC block configuration unit 19-2 adds a CP before the data symbol (effective block data) and sets null data at two consecutive UW positions. Then, block information having the same phase as the previous first block is set. Then, the SC block configuration unit 19-2 generates a first block in the order of two consecutive null data, block information, CP, and valid block data.

When the second block of the transmission signal x ₁ is generated, the SC block configuration unit 19-1 adds a CP before the data symbol (effective block data) and sets null data at two consecutive UW positions. Then, block information having a phase opposite to that of the previous second block is set. Then, the SC block configuration unit 19-1 generates a second block in the order of two consecutive null data, block information, CP, and valid block data.

When the second block of the transmission signal x ₂ is generated, the SC block configuration unit 19-2 adds a CP before the data symbol (effective block data), and the first block of the SC block configuration unit 19-1 Two consecutive UWs having the same phase as are set. In addition, the SC block configuration unit 19-2 sets block information having a phase opposite to that of the previous second block. Then, the SC block configuration unit 19-2 generates a second block in the order of two consecutive UWs, block information, CP, and valid block data.

Thus, in the first block and the second block, the UW of the transmission signal x ₁ generated by the SC block configuration unit 19-1 and the UW of the transmission signal x ₂ generated by the SC block configuration unit 19-2 are It becomes time-sharing data. In the first block, the SC block configuration units 19-1 and 19-2 set differential data having the same phase as the previous first block in the block information every time, and in the second block, the SC block configuration By the units 19-1 and 19-2, differential data having a phase opposite to that of the previous second block is set in the block information.

(When using third channel estimation method / third channel estimation method)
A case where the third signal format shown in FIG. 4 is used will be described. SC block generator 19-1 generates a signal of the third signal format of the transmission signal x ₁ shown in FIG. 4, SC block generator 19-2 first in the transmission signal x ₂ shown in FIG. 4 3 is generated.

Specifically, SC block generator 19-1, transmission signal when generating a preamble 1 x _1, by setting the (SC block configuration section 19-2 and the same phase) two consecutive UW A preamble 1 consisting of two consecutive UWs is generated. Moreover, SC block unit 19-2 when generating a preamble first transmission signal x _2, by setting the two consecutive UW in the same phase as the SC block portion 19-1, two consecutive A preamble 1 composed of UW is generated.

SC block generator 19-1, when generating a preamble 2 of the transmission signal x _1, by setting the UW continuous (preamble 1 and the same phase) of the two, the preamble 2 of two successive UW Is generated. Moreover, SC block unit 19-2 when generating a preamble 2 of the transmission signal x _2, by inverting the polarity of the UW (UW preamble 2) generated by the SC block portion 19-1, and this By setting two consecutive UWs having opposite phases, a preamble 2 composed of two consecutive UWs is generated.

  The SC block configuration units 19-1 and 19-2 add a CP before a data symbol (effective block data) when generating each block, so that each block is in the order of the CP and the effective block data. Is generated.

As a result, the UW of the transmission signal x ₁ generated by the SC block configuration unit 19-1 is the same for the preamble 1 and the preamble 2. Further, the UW of the transmission signal x ₂ generated by the SC block configuration unit 19-2 is inverted between the preamble 1 and the preamble 2.

(When using the fourth channel estimation method / fourth channel estimation method)
A case where the fourth signal format shown in FIG. 5 is used will be described. SC block generator 19-1 generates a signal of the fourth signal format of the transmission signal x ₁ shown in FIG. 5, SC block generator 19-2 first in the transmission signal x ₂ shown in FIG. 5 4 is generated.

Specifically, SC block generator 19-1, when generating a preamble first transmission signal x _1, by setting the two successive UW, generates a preamble 1 consisting of two successive UW . Further, when generating the preamble 1 of the transmission signal x ₂ , the SC block configuration unit 19-2 sets the two consecutive null data, thereby generating the preamble 1 including the two consecutive null data.

SC block generator 19-1, when generating a preamble 2 of the transmission signal x _1, by setting the two consecutive null, generates a preamble 2 of two successive null data. Moreover, SC block unit 19-2 when generating a preamble 2 of the transmission signal x _2, by setting the two consecutive UW in the same phase as the preamble 1 of SC block unit 19-1, 2 A preamble 2 consisting of two consecutive UWs is generated.

  The SC block configuration units 19-1 and 19-2 generate each block in the order of CP and data by adding the CP before the data symbol (effective block data) when generating each block. .

Accordingly, the preamble 1 and the preamble 2, and UW of the transmission signal x ₁ generated by the SC block portion 19-1, and the UW of the transmission signal x ₂ that is produced by the SC block unit 19-2, when The data is divided.

  Returning to FIG. 6, the band limiting filter 20-1 receives the signal after the SC block configuration which is a signal in a predetermined format from the SC block configuration unit 19-1, and performs band limitation using a route roll-off filter or the like. Then, the band limiting filter 20-1 outputs the band-limited signal to the digital quadrature modulation unit 21-1. The band limiting filter 20-2 of the transmission branch # 2 performs the same process as the band limiting filter 20-1.

  The digital quadrature modulation unit 21-1 receives the band-limited signal from the band-limiting filter 20-1, and quadrature-modulates the IF carrier with a baseband complex signal. Then, the digital quadrature modulation unit 21-1 outputs the signal after the quadrature modulation to the DA conversion unit 22-1. The digital quadrature modulation unit 21-2 of the transmission branch # 2 performs the same processing as the digital quadrature modulation unit 21-1.

  The DA conversion unit 22-1 receives the signal after quadrature modulation from the digital quadrature modulation unit 21-1, and converts the digital IF signal that is the signal after quadrature modulation into an analog IF signal. Then, the DA converter 22-1 outputs a modulation signal that is an analog IF signal to the transmission high-frequency unit 30-1. The DA conversion unit 22-2 of the transmission branch # 2 performs the same process as the DA conversion unit 22-1.

As described above, according to the transmission device 1 of the embodiment of the present invention, the SC block configuration units 19-1 and 19-2 of the SC-MIMO modulation unit 10 add the CP to the data of the effective block, and the channel response When a predetermined UW (see FIGS. 2 to 5) for estimating is set as a pilot symbol and the first or second channel estimation method (see FIGS. 2 and 3) is used, the first UW By setting block information for identifying the block and the second block at the time of MIMO signal separation, signals in any one of the first to fourth signal formats shown in FIGS. Generate each. Then, the transmission device 1 transmits transmission signals x ₁ and x ₂ in any one of the first to fourth signal formats shown in FIGS.

  In the embodiment of the present invention, as a UW for estimating the channel response, a Chu sequence or a Frank-Zadof sequence having a constant amplitude and excellent autocorrelation characteristics is used. As a result, the UW has a constant amplitude even in the frequency domain, the S / N ratio is uniform, and the correlation with the sequence shifted in timing can be zero, and the channel response can be accurately estimated on the receiving side. Is possible. That is, it is possible to solve the conventional problem that the accuracy of channel estimation is reduced due to the fact that the correlation of pilot signals different between transmission systems does not become zero completely.

  In the embodiment of the present invention, when the first or second channel estimation method (see FIGS. 2 and 3) is used, a UW for estimating a channel response is arranged for each block. Therefore, it can follow high-speed channel fluctuation. In other words, since the time length of the block in which the UW is arranged is shorter than that in Patent Document 3 in which the pilot symbol is arranged for each time slot, the conventional problem that the channel response error remains at the time of high-speed channel fluctuation can be solved. it can.

  Further, in the embodiment of the present invention, the UW for estimating the channel response is set to the same relatively short length as the CP which is about 1/8 of the effective block. Furthermore, two consecutive UWs were set, and the first half UW played the role of CP. Thereby, the channel response can be estimated corresponding to the delayed wave that falls within the CP time length (UW time length). Therefore, since the UW is a pilot length that is long enough to estimate a channel response that can cope with a delayed wave that falls within a relatively short time length, the transmission efficiency is high and many data transmissions are required for data transmission. You can spend time. That is, it is possible to solve the conventional problem that the transmission rate is lowered and the transmission efficiency is lowered due to the time length of the pilot symbol being longer than necessary.

  In this way, in the SC-MIMO scheme, it is possible to estimate the channel response with high accuracy using pilot symbols having a necessary and sufficient time length.

[Receiver]
Next, the receiving apparatus 2 shown in FIG. 1 will be described in detail. FIG. 7 is a block diagram illustrating a configuration example of the receiving device 2 according to the embodiment of the present invention. As illustrated in FIG. 1, the receiving device 2 includes two receiving antennas 50-1 and 50-2, receiving high-frequency units 60-1 and 60-2, and an SC-MIMO demodulating unit 70. In FIG. 7, the reception antenna 50-2 and the reception high-frequency unit 60-2 are omitted.

  The SC-MIMO demodulator 70 includes AD converters 71-1 and 71-2, digital orthogonal demodulators 72-1 and 72-2, band limiting filters 73-1 and 73-2, and block synchronizers 74-1 and 74. -2, noise power detection units 75-1 and 75-2, Fourier transform units 76-1 and 76-2, channel estimation units 77-1 and 77-2, a frequency domain MIMO signal separation unit 78, and an inverse Fourier transform unit 79 A determination / likelihood calculation unit 80, an inner deinterleaving unit 81, an inner code decoding unit 82, an outer deinterleaving unit 83, an outer code decoding unit 84, an energy despreading unit 85, and a data frame synchronization unit 86. In FIG. 7, components from the AD conversion unit 71-2 to the channel estimation unit 77-2 are omitted.

The reception antenna 50-1, the reception high-frequency unit 60-1, and the components from the AD conversion unit 71-1 to the channel estimation unit 77-1 included in the SC-MIMO demodulation unit 70, receive the first reception system. Branch # 1 is configured. The reception signal y ₁ (t) is received via the reception antenna 50-1 of the reception branch # 1.

A reception branch # 2 that is a second reception system is configured by a reception antenna 50-2, a reception high-frequency unit 60-2, and a configuration unit from the AD conversion unit 71-2 to the channel estimation unit 77-2 (not shown). . A reception signal y ₂ (t) is received via a reception antenna 50-2 (not shown) of the reception branch # 2.

  Since the reception antennas 50-1 and 50-2 and the reception high-frequency units 60-1 and 60-2 have already been described with reference to FIG.

  The AD conversion unit 71-1 of the reception branch # 1 in the SC-MIMO demodulation unit 70 receives the reception IF signal from the reception high frequency unit 60-1, and converts the analog IF signal that is the reception IF signal into a digital IF signal. Then, the AD conversion unit 71-1 outputs the digital IF signal to the digital quadrature demodulation unit 72-1. The AD conversion unit 71-2 (not shown) of the reception branch # 2 performs the same processing as the AD conversion unit 71-1.

  The digital quadrature demodulator 72-1 receives the digital IF signal from the AD converter 71-1, multiplies the digital IF signal by the IF carrier, and performs quadrature demodulation to generate a baseband complex signal. Then, the digital orthogonal demodulator 72-1 outputs the baseband complex signal to the band limiting filter 73-1. The digital quadrature demodulation unit 72-2 (not shown) of the reception branch # 2 performs the same processing as the digital quadrature demodulation unit 72-1.

  The band limiting filter 73-1 receives the baseband complex signal from the digital quadrature demodulator 72-1, and performs band limiting by a root roll-off filter or the like. Then, the band limiting filter 73-1 outputs the band-limited signal to the block synchronization unit 74-1. The band limitation filter 73-2 (not shown) of the reception branch # 2 performs the same processing as the band limitation filter 73-1.

  The block synchronizer 74-1 receives the band-limited signal from the band-limiting filter 73-1, detects the head of the block by a synchronization process for obtaining a correlation, and performs the above-described third or fourth channel estimation method. When used, the head of the preamble is further detected. Then, the block synchronization unit 74-1 outputs the signal subjected to the synchronization process to the noise power detection unit 75-1, the Fourier transform unit 76-1, and the channel estimation unit 77-1.

  When the first or second channel estimation method described above is used, a signal in which the head of the block is detected is output from the block synchronization unit 74-1. When the third or fourth channel estimation method described above is used, a signal in which the preamble head and the block head are detected is output from the block synchronization unit 74-1. The block synchronization unit 74-2 (not shown) of the reception branch # 2 performs the same processing as the block synchronization unit 74-1.

  Specifically, the block synchronization unit 74-1 performs the above-described first or second channel estimation method by performing a synchronization process for obtaining a cross-correlation between the band-limited signal and the known signal UW. When is used, the head of the block is detected. Further, when using the third or fourth channel estimation method described above, the block synchronization unit 74-1 detects the head of the preamble. In this case, the block synchronization unit 74-1 detects the beginning of the block or the beginning of the preamble by performing a synchronization process for obtaining a UW or CP sliding correlation that is repeatedly transmitted on the band-limited signal. Also good.

  When the first or second channel estimation method (see FIGS. 2 and 3) is used, the block synchronization unit 74-1 detects the head of the block and then immediately after two consecutive UWs. The block information inserted immediately before the CP is detected. Then, based on the block information, the block synchronization unit 74-1 determines whether the block (the block including the block information) is the first block or the second block. As described above, since the block information is information that makes it possible to identify the first block and the second block before MIMO signal separation is performed, the block synchronization unit 74-1 identifies the block. can do.

  For example, when DBPSK-modulated differential data is used as block information, the block synchronization unit 74-1 detects block information detected two blocks before the block data differential data detected in the current block. Differential demodulation with reference to the differential data. Then, when the differential demodulation result is the same phase (positive), the block synchronization unit 74-1 determines that the block is the first block, and the differential demodulation result is the opposite phase (negative). In this case, it is determined that the block is the second block. Then, the block synchronization unit 74-1 outputs a signal in which the head of the block is detected and the block is identified as a signal subjected to synchronization processing.

The noise power detection unit 75-1 receives the signal subjected to the synchronization process from the block synchronization unit 74-1, and is included in the received signal y ₁ (t) in the noise power included in the signal by a known process. The detected noise power n ₁ is detected. Then, the noise power detection unit 75-1 outputs the noise power n ₁ to the frequency domain MIMO signal separation unit 78.

The noise power detection unit 75-2 (not shown) of the reception branch # 2 detects the noise power n ₂ included in the reception signal y ₂ (t) by performing the same processing as the noise power detection unit 75-1. The noise power n ₂ is output to the frequency domain MIMO signal separation unit 78.

The Fourier transform unit 76-1 receives the signal subjected to the synchronization process from the block synchronization unit 74-1, detects the data of the effective block included in the input signal, and performs FFT on the data of the effective block. To generate a reception signal Y ₁ (f) in the frequency domain. Then, Fourier transform section 76-1 outputs frequency domain received signal Y ₁ (f) to frequency domain MIMO signal separation section 78.

The Fourier transform unit 76-2 (not shown) of the reception branch # 2 performs the same processing as the Fourier transform unit 76-1, thereby generating the frequency domain received signal Y ₂ (f) and the frequency domain received signal Y. ₂ (f) is output to the frequency domain MIMO signal separation unit 78.

The channel estimation unit 77-1 receives the signal subjected to the synchronization process from the block synchronization unit 74-1, detects two consecutive reception UWs included in the input signal, and 2 of the two reception UWs Based on the first received UW, channel responses H ₁₁ (f) and H ₁₂ (f) in the frequency domain are estimated. Then, the channel estimation unit 77-1 performs a predetermined interpolation process on the frequency domain channel responses H ₁₁ (f) and H ₁₂ (f), and the frequency domain channel responses H ₁₁ (f) and H ₁₁ after the interpolation process are performed. ₁₂ (f) is output to the frequency domain MIMO signal separation unit 78. The interpolation process will be described later.

A channel estimation unit 77-2 (not shown) of the reception branch # 2 performs processing similar to that of the channel estimation unit 77-1, thereby estimating channel responses H ₂₁ (f) and H ₂₂ (f) in the frequency domain, The frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) are output to the frequency domain MIMO signal separator 78.

(When using the first signal format / first channel estimation method)
A case where the first signal format shown in FIG. 2 is used will be described. The channel estimation unit 77-1 receives the reception UW of the first block and the second block of the reception signal y ₁ in which the signals of the first signal format in the transmission signals x ₁ and x ₂ shown in FIG. 2 are multiplexed. Based on the received UW, frequency domain channel responses H ₁₁ (f) and H ₁₂ (f) are estimated. The channel estimation unit 77-2, among the transmission signals x _1, the received signal signal of the first signal format is multiplexed in the x ₂ y ₂ shown in FIG. 2, the received UW, and the second of the first block Based on the received UW of the block, frequency domain channel responses H ₂₁ (f), H ₂₂ (f) are estimated. As described above, the first block and the second block have already been identified by the block synchronization units 74-1 and 74-2.

Specifically, the channel estimation unit 77-1 adds (adds) the second received UW of the two received UWs in the first block and the second received UW of the two received UWs in the second block. Perform FFT on the result. Then, the channel estimation unit 77-1 estimates the channel response H ₁₁ (f) in the frequency domain based on the FFT result of the reception UW and the result (reference signal) of FFT of the transmission UW.

The channel estimation unit 77-1 performs FFT on the difference (subtraction result) between the second received UW of the two received UWs of the first block and the second received UW of the two received UWs of the second block. I do. Then, the channel estimation unit 77-1 estimates the frequency domain channel response H ₁₂ (f) based on the FFT result of the reception UW and the reference signal of the transmission UW.

That is, the channel estimation unit 77-1 multiplies the reception UW of the first block and the second block and the orthogonal code assigned to each transmission system (multiply for each block, and adds the multiplication results between the blocks) Perform FFT on the result. Then, the channel estimation unit 77-1 estimates the frequency domain channel responses H ₁₁ (f) and H ₁₂ (f) based on the FFT result of the reception UW and the reference signal of the transmission UW.

The channel estimation unit 77-2 estimates the frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) by performing the same processing as the channel estimation unit 77-1.

(When using the second signal format / second channel estimation method)
A case where the second signal format shown in FIG. 3 is used will be described. The channel estimation unit 77-1 receives the reception UW of the first block and the second block of the reception signal y ₁ in which the signals of the second signal format in the transmission signals x ₁ and x ₂ shown in FIG. 3 are multiplexed. Based on the received UW, frequency domain channel responses H ₁₁ (f) and H ₁₂ (f) are estimated. The channel estimation unit 77-2, of the received signal y ₂ in which the second signal of the signal format in the transmission signal x _1, x ₂ are multiplexed as shown in FIG. 3, the received UW, and the second of the first block Based on the received UW of the block, frequency domain channel responses H ₂₁ (f), H ₂₂ (f) are estimated. As described above, the first block and the second block have already been identified by the block synchronization units 74-1 and 74-2.

Specifically, the channel estimation unit 77-1 performs FFT on the second received UW of the two received UWs of the first block, and based on the FFT result of the received UW and the reference signal of the transmitted UW, the frequency Estimate the channel response H ₁₁ (f) of the region. Further, the channel estimation unit 77-1 performs FFT on the second received UW of the two received UWs in the second block, and based on the FFT result of the received UW and the reference signal of the transmitted UW, the channel in the frequency domain Estimate the response H ₁₂ (f).

The channel estimation unit 77-2 estimates the frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) by performing the same processing as the channel estimation unit 77-1.

(When using third channel estimation method / third channel estimation method)
A case where the third signal format shown in FIG. 4 is used will be described. The channel estimation unit 77-1 receives the preamble 1 reception UW and the preamble 2 reception UW among the reception signals y ₁ in which the signals of the third signal format in the transmission signals x ₁ and x ₂ shown in FIG. 4 are multiplexed. Is used to estimate the frequency domain channel responses H ₁₁ (f), H ₁₂ (f). The channel estimation unit 77-2, of the received signal y ₂ in which the signal of the third signal format of the transmission signals x _1, x ₂ shown in FIG. 4 are multiplexed, the preamble 1 reception UW and preamble 2 Based on the received UW, frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) are estimated.

Specifically, channel estimation unit 77-1 sums the second received UW of the two received UWs of preamble 1 and the second received UW of the two received UWs of preamble 2 (addition result). FFT is performed on the. Then, the channel estimation unit 77-1 estimates the channel response H ₁₁ (f) in the frequency domain based on the FFT result of the reception UW and the reference signal of the transmission UW.

Channel estimation section 77-1 performs FFT on the difference (subtraction result) between the second received UW of the two received UWs of preamble 1 and the second received UW of the two received UWs of preamble 2. . Then, the channel estimation unit 77-1 estimates the channel response H ₁₂ (f) in the frequency domain based on the FFT result of the reception UW and the reference signal of the transmission UW.

That is, channel estimation section 77-1 multiplies the received UW of preamble 1 and preamble 2 and the orthogonal code assigned to each transmission system (the result of multiplying for each preamble and adding the multiplication result between the preambles). FFT is performed on the. Then, the channel estimation unit 77-1 estimates the frequency domain channel responses H ₁₁ (f) and H ₁₂ (f) based on the FFT result of the reception UW and the reference signal of the transmission UW.

The channel estimation unit 77-2 estimates the frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) by performing the same processing as the channel estimation unit 77-1.

(When using the fourth channel estimation method / fourth channel estimation method)
A case where the fourth signal format shown in FIG. 5 is used will be described. The channel estimation unit 77-1 receives the preamble U1 reception UW and the preamble U2 reception UW among the reception signals y ₁ in which the signals of the fourth signal format in the transmission signals x ₁ and x ₂ shown in FIG. 5 are multiplexed. Is used to estimate the frequency domain channel responses H ₁₁ (f), H ₁₂ (f). The channel estimation unit 77-2, of the received signal y ₂ in which the signal of the fourth signal format of the transmission signals x _1, x ₂ shown in FIG. 5 are multiplexed, preamble 1 reception UW and preamble 2 Based on the received UW, frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) are estimated.

Specifically, the channel estimation unit 77-1 performs FFT on the second received UW of the two received UWs of the preamble 1, and based on the FFT result of the received UW and the reference signal of the transmitted UW, the frequency domain Channel response H ₁₁ (f). Further, the channel estimation unit 77-1 performs FFT on the second received UW of the two received UWs of the preamble 2, and based on the FFT result of the received UW and the reference signal of the transmitted UW, the frequency domain channel response Estimate H ₁₂ (f).

The channel estimation unit 77-2 estimates the frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) by performing the same processing as the channel estimation unit 77-1.

As described above, the length of UW is 1/8 of the length of the effective block (see FIGS. 2 to 5). For this reason, the frequency interval of the frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f) estimated based on UW is the signal in the frequency domain of the effective block. Longer than the ingredients.

Therefore, the channel estimation units 77-1 and 77-2 set the frequency interval of the frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f) to the effective block. In order to equalize the frequency domain signal components, interpolation processing is performed on the frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f). Then, the frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f) after the interpolation processing are output to the frequency domain MIMO signal separation unit 78.

Returning to FIG. 7, the frequency domain MIMO signal separation unit 78 receives the noise power n ₁ from the noise power detection unit 75-1 of the reception branch # 1, and receives the frequency domain reception signal Y ₁ (f from the Fourier transform unit 76-1. ) Are input from the channel estimation unit 77-1 as frequency domain channel responses H ₁₁ (f) and H ₁₂ (f), respectively. Further, the frequency domain MIMO signal separation unit 78 receives the noise power n ₂ from the noise power detection unit 75-2 of the reception branch # 2, the frequency domain reception signal Y ₂ (f) from the Fourier transform unit 76-2, and the channel. Frequency domain channel responses H ₂₁ (f) and H ₂₂ (f) are input from the estimation unit 77-2.

The frequency domain MIMO signal separation unit 78 includes noise powers n ₁ and n ₂ , frequency domain received signals Y ₁ (f) and Y ₂ (f), and channel responses H ₁₁ (f), H ₁₂ (f), and H _21. Based on (f) and H ₂₂ (f), MIMO signal separation is performed by the ZF algorithm or the MMSE algorithm. Then, the frequency domain MIMO signal separation unit 78 estimates the frequency domain transmission signals X ₁ (f) and X ₂ (f). The frequency domain MIMO signal separation unit 78 then outputs the frequency domain transmission signals X ₁ (f) and X ₂ (f) to the inverse Fourier transform unit 79.

The inverse Fourier transform unit 79 receives the frequency domain transmission signals X ₁ (f) and X ₂ (f) from the frequency domain MIMO signal separation unit 78 and receives the frequency domain transmission signals X ₁ (f) and X ₂ (f ) To generate time-domain transmission signals x ₁ (t) and x ₂ (t). Then, the inverse Fourier transform unit 79 outputs the time domain transmission signals x ₁ (t) and x ₂ (t) to the determination / likelihood calculation unit 80.

The determination / likelihood calculation unit 80 receives the time domain transmission signals x ₁ (t) and x ₂ (t) from the inverse Fourier transform unit 79, and the time domain transmission signals x ₁ (t) and x ₂ (t ) And a known transmission signal to determine the closest transmission signal. Alternatively, the determination / likelihood calculation unit 80 calculates the bit likelihood (probability of 0 or 1 for each bit) for the transmission signals x ₁ (t) and x ₂ (t) in the time domain. Then, the determination / likelihood calculation unit 80 outputs the signal after determination or calculation to the internal deinterleaving unit 81.

  The inner deinterleaving unit 81 receives the signal after the determination or calculation from the determination / likelihood calculating unit 80 and performs the reverse processing of the inner interleaving units 17-1 and 17-2 shown in FIG. Perform deinterleaving. Then, the inner deinterleaving unit 81 outputs the signal after the inner deinterleaving to the inner code decoding unit 82.

  The inner code decoding unit 82 receives the signal after the inner deinterleaving from the inner deinterleaving unit 81, and performs inner code decoding of the error correction code corresponding to the inner code encoding unit 15 shown in FIG. Then, the inner code decoding unit 82 outputs the signal after inner code decoding to the outer deinterleaving unit 83.

  The outer deinterleaving unit 83 receives the signal after inner code decoding from the inner code decoding unit 82 and performs the reverse processing of the outer interleaving unit 14 shown in FIG. 6 to perform outer deinterleaving. Then, the outer deinterleaving unit 83 outputs the signal after the outer deinterleaving to the outer code decoding unit 84.

  The outer code decoding unit 84 receives the signal after the outer deinterleaving from the outer deinterleaving unit 83, and performs outer code decoding of the error correction code corresponding to the outer code coding unit 13 shown in FIG. Then, outer code decoding section 84 outputs the signal after outer code decoding to energy despreading section 85.

  The energy despreading unit 85 inputs the signal after outer code decoding from the outer code decoding unit 84, and performs an exclusive OR operation with the same pseudorandom code used in the energy spreading unit 12 shown in FIG. Return to the original data packet. Then, the energy despreading unit 85 outputs the restored data packet to the data frame synchronization unit 86.

  The data frame synchronization unit 86 receives the data packet from the energy despreading unit 85 and performs the reverse processing of the data frame synchronization unit 11 shown in FIG. 6 to restore the data frame configuration to the original information. Is generated. Then, the data frame synchronization unit 86 outputs the original information.

As described above, according to the receiving device 2 of the embodiment of the present invention, the block synchronization units 74-1 and 74-2 of the SC-MIMO demodulation unit 70 are synchronized to obtain correlations with respect to the received signals y ₁ and y _2. By processing, the head of the block is detected, and the head of the preamble is detected. Further, when using the first or second channel estimation method (see FIGS. 2 and 3), the block synchronization units 74-1 and 74-2 detect block information, and based on the block information, the block Is a first block or a second block.

When using the first or second channel estimation method (see FIGS. 2 and 3), the channel estimation units 77-1 and 77-2 are based on the reception UW of the first block and the reception UW of the second block. The frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f) are estimated. Further, when the third or fourth channel estimation method (see FIGS. 4 and 5) is used, the channel estimation units 77-1 and 77-2 are based on the reception UW of the preamble 1 and the reception UW of the preamble 2. Thus, frequency domain channel responses H ₁₁ (f), H ₁₂ (f), H ₂₁ (f), and H ₂₂ (f) are estimated.

  In the embodiment of the present invention, the Chu sequence or the Frank-Zadof sequence is used as the UW for estimating the channel response. Thereby, the correlation between transmission systems can be set to 0, and the channel response can be estimated with high accuracy. That is, it is possible to solve the conventional problem that the accuracy of channel estimation is reduced due to the fact that the correlation between transmission systems does not become completely zero.

  In the embodiment of the present invention, when the first or second channel estimation method (see FIGS. 2 and 3) is used, a UW for estimating a channel response is arranged for each block. Therefore, it can follow high-speed channel fluctuation. In other words, since the time length of the block in which the UW is arranged is shorter than that in Patent Document 3 in which the pilot symbol is arranged for each time slot, the conventional problem that the channel response error remains at the time of high-speed channel fluctuation can be solved. it can.

  In the embodiment of the present invention, the UW for estimating the channel response is set to the same relatively short length as the CP, which is about 1/8 of the effective block, and two consecutive UWs The first half of the UW played the role of CP. Thereby, the channel response can be estimated corresponding to the delayed wave that falls within the CP time length (UW time length). Therefore, since the UW is a pilot length that is long enough to estimate a channel response that can cope with a delayed wave that falls within a relatively short time length, the transmission efficiency is high and many data transmissions are required for data transmission. You can spend time. That is, it is possible to solve the conventional problem that the transmission rate decreases and the transmission efficiency decreases due to the time length of the pilot symbol being longer than necessary.

  In this way, in the SC-MIMO scheme, it is possible to estimate the channel response with high accuracy using pilot symbols having a necessary and sufficient time length.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the technical idea thereof. For example, the embodiment of the present invention shown in FIG. 1 is an example using a 2 × 2 SC-MIMO scheme of 2 transmissions and 2 receptions. The present invention is applicable not only to the 2 × 2 SC-MIMO scheme with two transmissions and two receptions, but also to other SC-MIMO schemes. In short, the present invention is applicable to an SC-MIMO system corresponding to a plurality of transmission antennas and a single or a plurality of reception antennas.

  In the SC-MIMO scheme corresponding to a plurality of transmission antennas and a single or a plurality of reception antennas, the number of transmission antennas (the number of transmission branches and the number of transmission systems) is n (n is an integer of 2 or more), and the number of reception antennas ( The number of reception branches and the number of reception systems is m (m is an integer of 1 or more).

  When the first channel estimation method is used, the SC-MIMO modulation unit 10 of the transmission device 1 uses orthogonal codes whose orthogonal length is n or more in a plurality of transmission systems, and has the same number as the length of the orthogonal codes. By multiplying (multiplying) two consecutive UWs by the orthogonal code over the block, two consecutive UWs reflecting the orthogonal code are set.

  FIG. 9 is a diagram illustrating a first signal format when the number of transmission antennas is 4 (n = 4). For example, when the number of transmitting antennas is 4 (n = 4), (1, 1, 1, 1), (1, -1, 1, -1), (1, 1) having a length of 4 as orthogonal codes. , -1, -1), (1, -1, -1, 1).

As shown in FIG. 9, SC-MIMO modulation unit 10, to the transmission signal _{x 1,} sets two consecutive UW from the first block to the fourth block in the same phase. Further, the SC-MIMO modulation unit 10 reverses the two consecutive UWs of the second block and the fourth block with respect to the transmission signal x ₂ with the two consecutive UWs of the first block and the third block in the same phase. Set to phase. Further, the SC-MIMO modulation unit 10 reverses two consecutive UWs of the third block and the fourth block with the same phase of the two consecutive UWs of the first block and the second block with respect to the transmission signal x _3. Set to phase. Further, SC-MIMO modulation unit 10, to the transmission signal _{x 4,} two consecutive UW of the first block and the fourth block in the same phase, reverse two consecutive UW of the second block and the third block Set to phase.

  The SC-MIMO demodulator 70 of the receiver 2 multiplies the received UWs from the first block to the fourth block and the orthogonal code assigned to each transmission system (multiplies each block, and multiplies the multiplication result between blocks). FFT is performed on the result of addition in (1). Then, the SC-MIMO demodulator 70 estimates the channel response in the frequency domain based on the FFT result of the reception UW and the reference signal of the transmission UW.

When using the second channel estimation method, SC-MIMO modulation unit 10 of the transmitting apparatus 1, for each block, the transmission signal x _1, · ·, a single transmission signal of x _n, other blocks Two consecutive UWs (for one transmission system of the transmission systems of transmission signals x ₁ ,..., X _n and different transmission systems from other blocks) Set. Then, SC-MIMO modulation section 10 sets null data at two consecutive UW positions for other transmission signals.

FIG. 10 is a diagram illustrating a second signal format when the number of transmission antennas is 4 (n = 4). For example, when the number of transmission antennas is 4 (n = 4), as shown in FIG. 10, the SC-MIMO modulation unit 10 sets two consecutive UWs for the transmission signal x ₁ for the first block. Null data is set at two consecutive UW positions for the transmission signals x ₂ , x ₃ , and x ₄ . Then, the SC-MIMO modulation unit 10 sets two continuous UWs for the transmission signal x ₂ for the second block, and sets two continuous UWs for the transmission signals x ₁ , x ₃ , and x ₄ . Set null data to the position. Then, the SC-MIMO modulation unit 10 sets two consecutive UWs for the transmission signal x ₃ for the third block, and sets two consecutive UWs for the transmission signals x ₁ , x ₂ , and x ₄ . Set null data to the position. Further, the SC-MIMO modulation unit 10 sets two consecutive UWs for the transmission signal x ₄ for the fourth block, and sets two consecutive UWs for the transmission signals x ₁ , x ₂ , and x ₃ . Set null data to the position.

  The SC-MIMO demodulator 70 of the receiving apparatus 2 performs FFT on the reception UW of each block, and estimates the frequency domain channel response based on the FFT result of the reception UW and the reference signal of the transmission UW.

  The third channel estimation method is realized by replacing the block of the first channel estimation method with a preamble. The fourth channel estimation method is realized by replacing the block of the second channel estimation method with a preamble.

DESCRIPTION OF SYMBOLS 1 Transmission apparatus 2 Reception apparatus 10 SC-MIMO modulation part 11 Data frame synchronization part 12 Energy spreading part 13 Outer code encoding part 14 Outer interleaving part 15 Inner code encoding part 16 Inter-system distribution part 17 Inner interleaving part 18 Mapping part 19 SC block configuration unit 20 Band limiting filter 21 Digital quadrature modulation unit 22 DA conversion unit 30 Transmission high frequency unit 40 Transmission antenna 50 Reception antenna 60 Reception high frequency unit 70 SC-MIMO demodulation unit 71 AD conversion unit 72 Digital orthogonal demodulation unit 73 Band limitation filter 74 Block synchronization unit 75 Noise power detection unit 76 Fourier transform unit 77 Channel estimation unit 78 Frequency domain MIMO signal separation unit 79 Inverse Fourier transform unit 80 Determination / likelihood calculation unit 81 Inner deinterleaving unit 82 Inner code decoding unit 83 Outer deinterleaving 84 Outer code decoding unit 85 Energy despreading unit 86 Data frame synchronization unit

Claims (8)

Pilot for performing MIMO modulation on data to be transmitted and estimating a channel response between the plurality of transmission antennas and one or a plurality of reception antennas included in the single carrier MIMO receiver via a plurality of transmission antennas In a single carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a signal to the single carrier MIMO reception apparatus by a single carrier,
An inter-system distribution unit that distributes the transmission target data to a plurality of transmission systems corresponding to the plurality of transmission antennas;
A CP (cyclic prefix), which is a copy of a predetermined portion after the data, is added to the data of the effective block of a predetermined length in the data distributed by the inter-system distribution unit, and the pilot signal is the same as the CP Set as length UW (unique word), set block information for identifying one block from a plurality of consecutive blocks, and set two consecutive UW, block information, CP and effective block A block configuration unit that generates a block of data for each transmission system, and
The block constituent unit is:
Wherein for each of a plurality of consecutive blocks,-out based on the orthogonal code which is orthogonal in the plurality of transmission systems, I set the UW two consecutive same symbols, single-carrier MIMO transmission apparatus characterized by. Pilot for performing MIMO modulation on data to be transmitted and estimating a channel response between the plurality of transmission antennas and one or a plurality of reception antennas included in the single carrier MIMO receiver via a plurality of transmission antennas In a single carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a signal to the single carrier MIMO reception apparatus by a single carrier,
An inter-system distribution unit that distributes the transmission target data to a plurality of transmission systems corresponding to the plurality of transmission antennas;
A CP (cyclic prefix), which is a copy of a predetermined portion after the data, is added to the data of the effective block of a predetermined length in the data distributed by the inter-system distribution unit, and the pilot signal is the same as the CP Set as length UW (unique word), set block information for identifying one block from a plurality of consecutive blocks, set two consecutive UW or null data, block information, CP and valid A block configuration unit that generates a block composed of block data for each transmission system, and
The block constituent unit is:
For each of the plurality of consecutive blocks, two consecutive transmission systems that are one transmission system of the plurality of transmission systems and different from the transmission system in which the UW is set in another block The null data is set in place of two consecutive UWs with respect to a transmission system in which the UW is set and is another transmission system of the plurality of transmission systems and the UW is set in the other block. A single carrier MIMO transmitter characterized in that it is set. Pilot for performing MIMO modulation on data to be transmitted and estimating a channel response between the plurality of transmission antennas and one or a plurality of reception antennas included in the single carrier MIMO receiver via a plurality of transmission antennas In a single carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a signal to the single carrier MIMO reception apparatus by a single carrier,
An inter-system distribution unit that distributes the transmission target data to a plurality of transmission systems corresponding to the plurality of transmission antennas;
A CP (cyclic prefix), which is a copy of a predetermined portion after the data, is added to the data of the effective block of a predetermined length in the data distributed by the inter-system distribution unit, and the pilot signal is the same as the CP Set as a length UW (unique word), a single preamble constitutes a plurality of preambles comprising two consecutive UWs, and a block constitutes the CP and the valid block data A block configuration unit that generates a plurality of blocks for each transmission system, and
The block constituent unit is:
For each of a plurality of preambles successive-out based on the orthogonal code which is orthogonal in the plurality of transmission systems, sets the UW two successive same symbols, single-carrier MIMO transmission apparatus characterized by. Pilot for performing MIMO modulation on data to be transmitted and estimating a channel response between the plurality of transmission antennas and one or a plurality of reception antennas included in the single carrier MIMO receiver via a plurality of transmission antennas In a single carrier MIMO transmission apparatus that wirelessly transmits a transmission signal including a signal to the single carrier MIMO reception apparatus by a single carrier,
An inter-system distribution unit that distributes the transmission target data to a plurality of transmission systems corresponding to the plurality of transmission antennas;
A CP (cyclic prefix), which is a copy of a predetermined portion after the data, is added to the data of the effective block of a predetermined length in the data distributed by the inter-system distribution unit, and the pilot signal is the same as the CP Set as length UW (unique word), a single preamble constitutes a plurality of preambles composed of two consecutive UW or null data, and a block constitutes data of the CP and the effective block A plurality of blocks to be generated for each transmission system, and a block configuration unit,
The block constituent unit is:
For each of the plurality of preamble continuous, a single transmission system of the plurality of transmission systems, for different transmission lines and transmission lines the UW is set in other preambles, two consecutive The null data is set in place of two consecutive UWs with respect to a transmission system in which the UW is set and is another transmission system of the plurality of transmission systems and the UW is set in the other preamble. A single carrier MIMO transmitter characterized in that it is set. A transmission signal transmitted via a plurality of transmission antennas included in the single carrier MIMO transmission apparatus according to claim 1 is received via one or a plurality of reception antennas, and two consecutive UWs, block information, CP, and valid By performing MIMO demodulation on a received signal in which blocks consisting of block data are multiplexed, channel responses between the plurality of transmitting antennas and the one or more receiving antennas are estimated and transmitted from the plurality of transmitting antennas. In a single carrier MIMO receiver that separates the received signal and restores the original transmission target data,
A synchronization process for obtaining a correlation with the received signal detects the beginning of the block of the received signal, detects the block information from the block of the received signal, and identifies the block of the received signal based on the block information A block synchronization unit;
The block synchronization unit identifies the block in which UWs set based on orthogonal codes for all of a plurality of transmission systems are multiplexed,
FFT (Fast Fourier Transform) is performed using the received UW subsequent to the consecutive received UWs included in the block, and the channel response is estimated based on the FFT result and a preset reference signal. A single-carrier MIMO receiver comprising: a channel estimation unit; A transmission signal transmitted via a plurality of transmission antennas provided in the single carrier MIMO transmission apparatus of claim 2 is received via one or a plurality of reception antennas, and two consecutive UW or null data, block information, CP And, by performing MIMO demodulation on a received signal in which blocks including data of effective blocks are multiplexed, channel responses between the plurality of transmitting antennas and the one or more receiving antennas are estimated, and the plurality of transmitting antennas In a single carrier MIMO receiving apparatus that separates the signal transmitted from, and restores the original transmission target data,
A synchronization process for obtaining a correlation with the received signal detects the beginning of the block of the received signal, detects the block information from the block of the received signal, and identifies the block of the received signal based on the block information A block synchronization unit;
The block synchronization unit identifies the block in which UW for one transmission system of a plurality of transmission systems and null data for another transmission system are multiplexed,
FFT (Fast Fourier Transform) is performed using the received UW subsequent to the consecutive received UWs included in the block, and the channel response is estimated based on the FFT result and a preset reference signal. A single-carrier MIMO receiver comprising: a channel estimation unit; A transmission signal transmitted via a plurality of transmission antennas included in the single carrier MIMO transmission apparatus of claim 3 is received via one or a plurality of reception antennas, and a preamble composed of two consecutive UWs is multiplexed. By performing MIMO demodulation on a received signal and a received signal in which a block composed of CP and effective block data is multiplexed, a channel response between the plurality of transmitting antennas and the one or more receiving antennas is estimated. In a single carrier MIMO receiver that separates signals transmitted from the plurality of transmission antennas and restores the original transmission target data,
A block synchronization unit for detecting a head of a preamble of the received signal and a head of a block of the received signal by a synchronization process for obtaining a correlation with the received signal;
The block synchronization unit detects the preamble in which UWs set based on orthogonal codes for all of a plurality of transmission systems are multiplexed,
An FFT (Fast Fourier Transform) is performed using a reception UW subsequent to the consecutive reception UWs included in the preamble, and the channel response is estimated based on the FFT result and a preset reference signal. A single-carrier MIMO receiver comprising: a channel estimation unit; The transmission signal transmitted through the plurality of transmission antennas of the single carrier MIMO transmission apparatus according to claim 4 is received through one or a plurality of reception antennas, and a preamble composed of two consecutive UW or null data is multiplexed. By performing MIMO demodulation on a received signal and a received signal in which a block composed of CP and effective block data is multiplexed, a channel response between the plurality of transmitting antennas and the one or more receiving antennas is estimated. In the single carrier MIMO receiver that separates the signals transmitted from the plurality of transmission antennas and restores the original transmission target data,
A block synchronization unit for detecting a head of a preamble of the received signal and a head of a block of the received signal by a synchronization process for obtaining a correlation with the received signal;
The block synchronization unit detects the preamble in which UW for one transmission system of a plurality of transmission systems and null data for another transmission system are multiplexed,
An FFT (Fast Fourier Transform) is performed using a reception UW subsequent to the consecutive reception UWs included in the preamble, and the channel response is estimated based on the FFT result and a preset reference signal. A single-carrier MIMO receiver comprising: a channel estimation unit;

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