JP2023070493A - Single-carrier MIMO transmitter and single-carrier MIMO receiver - Google Patents

Abstract

An object of the present invention is to improve transmission efficiency when performing MIMO transmission using an SC-FDE scheme. A pilot signal inserting unit 15-1 of a transmitting device 1 arranges two consecutive UWs or null data on a diagonal line (A) for symbol sequences of the same number of blocks as the number of transmissions, and generates a pilot signal group. is composed of UW and null data (B), the number of pilot signal symbols c is a power of 2 (C), the number of MIMO detection range symbols SS is a power of 2, a is the number of MIMO block number symbols, b is data The number of symbols, c is the number of pilot signal symbols, and d is the number of MIMO transmissions, SS = (a + b) × d + c × (2 × d−1) (D), and 2 included in the first block of the detection target block The pilot signals are inserted at predetermined positions so that the block configuration satisfies the (E) condition that two consecutive pilot signals are the same. [Selection drawing] Fig. 2

Description

The present invention relates to a single-carrier MIMO (Multiple Input Multiple Output) transmitter and a single-carrier MIMO receiver that can be used in a radio transmission system such as broadcasting or communication, and in particular, MIMO SC-FDE that performs channel equalization in the frequency domain. (Single Carrier-Frequency Domain Equalization) method.

2. Description of the Related Art Conventionally, in radio transmission systems for fixed transmission such as broadcasting or communication, a single carrier system using one carrier wave has been widely used. On the other hand, in wireless transmission systems in mobile environments, multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) using multiple carriers can follow high-speed channel fluctuations by performing channel equalization in the frequency domain on a symbol-by-symbol basis. method is commonly used.

The OFDM system is suitable for mobile transmission, but compared to the single-carrier system, the PAPR (Peak to Average Power Ratio), which is the ratio of the peak power to the average power of the transmitted signal, is generally large, so it is susceptible to nonlinear distortion of the power amplifier. It is weak and the operating point of the power amplifier should be used in the highly linear region. Therefore, it is often operated with a large output back-off from the output level (P1dB) at which the 1dB gain is lowered with respect to the ideal linear gain, resulting in low power efficiency.

In recent years, among single-carrier systems, an SC-FDE system has been proposed that performs channel equalization in the frequency domain (processing to restore amplitude and phase changes occurring in the propagation path) (for example, Non-Patent Document 1 and See Patent Document 1).

In the SC-FDE scheme, channel estimation and channel equalization in the frequency domain are performed in units of a constant number of consecutive symbols (in units of blocks), so that high-speed channel fluctuations in mobile transmission can be followed. Therefore, the SC-FDE system is more suitable for mobile transmission than the conventional single-carrier system that performs channel equalization in the time domain.

Generally, in the SC-FDE system, inter-block interference in a multipath environment can be prevented by providing a guard interval (GI) as in the OFDM system. A receiver that applies the SC-FDE scheme performs block synchronization to detect the beginning of a block, and unique word (UW), which is a pilot signal for channel estimation (fixed pattern signal known in transmitter and receiver) and Extract data. Then, the receiving apparatus transforms the UW and data into the frequency domain by Fourier transform, and performs channel estimation and channel equalization processing. Thereafter, the receiving apparatus restores the data to a time-domain signal by inverse Fourier transform, and performs processing such as symbol determination.

Since the SC-FDE system generally has a lower PAPR than the OFDM system, it is possible to reduce the output back-off of the power amplifier, enabling highly efficient operation of the power amplifier, and increasing the power consumption in mobile transmission. It is also possible to reduce the size of the amplifier.

Furthermore, a MIMO SC-FDE scheme has been proposed that supports MIMO in which a large amount of information is wirelessly transmitted at high speed using a plurality of antennas (see Patent Document 2, for example). In MIMO, a plurality of signals are transmitted according to the number of transmissions (multiplexing number), and reception is performed in a state where these signals are mixed with each other.

Therefore, MIMO detection (MIMO channel estimation and equalization in the frequency domain) for detecting the original transmission signal from the received signal is required in the receiving device. In order to distinguish a plurality of transmission signals, arrangements are made so that the UW positions are different over a plurality of blocks, and the transmission signals are orthogonal among the transmission systems.

FIG. 9 is a diagram showing a symbol block configuration of a null structure of the MIMO SC-FDE scheme in the prior art, and shows a case where the number of transmissions is two. A transmission signal _x1 indicates a signal transmitted from the first transmission system in the transmission device, and a transmission signal _x2 indicates a signal transmitted from the second transmission system.

The transmission signals x ₁ and x ₂ are configured in units of two blocks, a MIMO odd block and a MIMO even block. When the number of transmissions is 2, MIMO detection is performed in the receiving apparatus in units of these two blocks.

Each block of the transmission signals x ₁ and x ₂ is composed of two consecutive UWs or null data, GI with CP (Cyclic Prefix) inserted after the data, MIMO block number and data.

UW and null data are pilot signals used for channel estimation. UW consists of a known fixed pattern between transmission and reception, and CAZAC (Constant Amplitude Zero Auto-Correlation) sequences with excellent periodic autocorrelation characteristics such as Zadoff-Chu sequences with constant amplitude in the time domain and frequency domain are used. be done. The CP is information obtained by copying the latter part of the data, and is necessary for performing conversion between the time domain and the frequency domain.

The MIMO block number is information for identifying where each of the multiple blocks starts so that the receiving device can perform MIMO detection correctly. The MIMO block number identifies the first MIMO odd block and the second MIMO even block before MIMO signal separation is performed.

A symbol sequence obtained by differentially modulating a value corresponding to 1 is set as a MIMO block number in a MIMO odd block, and a symbol sequence obtained by differentially modulating a value corresponding to 2 is set as a MIMO block number in a MIMO even block. be done. As the differential modulation, a system capable of differential detection such as DBPSK (Differential Binary Phase Shift Keying) or DQPSK (Differential Quadrature Phase Shift Keying) is used.

The MIMO block number is generated using the differential modulation scheme described above and placed in the symbol sequence to be equalized. This makes it possible to improve the identification accuracy and transmission efficiency of the UW positional relationship (see Patent Document 3, for example).

As shown in FIG. 9, in two consecutive blocks, the presence and absence of two consecutive UWs (null data) are alternately set in the two transmission systems.

As a result, the MIMO SC-FDE scheme can improve the transmission rate more than the SISO (Single Input Single Output) (SISO SC-FDE scheme) using the SC-FDE scheme of Patent Document 1 described above.

Japanese Patent No. 5624527 Japanese Patent No. 6612106 JP 2019-140590 A

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

However, in the MIMO SC-FDE scheme of Patent Document 2 described above, the CP is individually added to the signal to be equalized, whereas in the SISO SC-FDE scheme of Patent Document 1 described above, the UW is Since it also serves as CP, CP is not added separately.

Therefore, the MIMO SC-FDE scheme has a lower ratio of data to transmission signals (data efficiency) than the SISO SC-FDE scheme. It has been desired to improve transmission efficiency in the MIMO SC-FDE scheme.

Therefore, the present invention has been made to solve the above problems, and its object is to improve the transmission efficiency when performing MIMO transmission using the SC-FDE method. and to provide a single-carrier MIMO receiver.

In order to solve the above problem, the single-carrier MIMO transmission apparatus of claim 1 includes a plurality of transmission antennas, and for each of a plurality of transmission systems corresponding to the plurality of transmission antennas, a block of the MIMO SC-FDE scheme is used. a single-carrier MIMO transmission device that generates and transmits modulated waves of the block for each transmission system via the transmission antenna, and distributes a coded bit sequence of data to be transmitted to the plurality of transmission systems. and an inter-system sorting unit that performs mapping using a predetermined modulation method on the encoded bit sequence of the data to be transmitted sorted by the inter-system sorting unit, and outputs the bit sequence after mapping. and a MIMO for each transmission system that inserts a MIMO block number at a predetermined position into the bit sequence after mapping output by the mapping unit, and outputs a symbol sequence in which the MIMO block number is inserted. a block number inserting unit; inserting two consecutive pilot signals at predetermined positions into a symbol sequence in which the MIMO block number output by the MIMO block number inserting unit is inserted, and inserting the two consecutive pilot signals; , a pilot signal inserting unit for each transmission system that generates a symbol sequence of a detection target block composed of the same number of blocks as the number of transmission systems, in units of the block composed of the MIMO block number and the data to be transmitted; wherein the number of symbols of the MIMO block number is the number of MIMO block number symbols, the number of symbols of the data to be transmitted is the number of data symbols, b is the number of symbols of the pilot signal, the number of pilot signal symbols is c, and the plurality of Let the number of transmitting antennas be the number of MIMO transmissions d, let the number of symbols in the MIMO detection range to be equalized in the frequency domain be the number of MIMO detection range symbols SS, and let the MIMO detection range be the first block in the detection target block. from the MIMO block number included in the detection target block to the leading pilot signal included in the first block in the detection target block next to the detection target block, the pilot signal inserting unit performs the above in the plurality of transmission systems When a matrix is configured with the two consecutive pilot signals included in the detection target block as one element, two consecutive UW (unique word) elements consisting of known fixed pattern signals are on the diagonal of the matrix (A), and among all the pilot signals constituting the matrix, the pilot signals other than the two consecutive UWs arranged on the diagonal line are null data (B), and the pilot The signal symbol number c is a power of 2 (C), the MIMO detection range symbol number SS is a power of 2, and is expressed by the formula: SS=(a+b)×d+c×(2×d−1). (D) and (E) that the two consecutive pilot signals contained in the first block in the detection target block are the same, so that the two consecutive pilot signals are matched so as to satisfy the respective conditions. It is characterized by inserting it at a predetermined position to generate a symbol sequence of the block to be detected.

Further, the single-carrier MIMO transmission apparatus of claim 2 includes a plurality of transmission antennas, generates a MIMO SC-FDE block for each of a plurality of transmission systems corresponding to the plurality of transmission antennas, and generates a block for each transmission system. an inter-system distribution unit that distributes a coded bit sequence of data to be transmitted to the plurality of transmission systems in a single-carrier MIMO transmission device that transmits the modulated wave of the block of through the transmission antenna a mapping unit for each transmission system that performs mapping by a predetermined modulation method on the encoded bit sequence of the data to be transmitted distributed by the inter-system allocation unit and outputs a bit sequence after mapping; a MIMO block number inserting unit for each transmission system that inserts a MIMO block number at a predetermined position in the mapped bit sequence output by the mapping unit and outputs a symbol sequence in which the MIMO block number is inserted; Two consecutive pilot signals are inserted at a predetermined position into the symbol sequence in which the MIMO block number is inserted, which is output by the MIMO block number inserting unit, and the two consecutive pilot signals, the MIMO block number and a pilot signal inserting unit for each transmission system that generates a symbol sequence of a detection target block composed of the same number of blocks as the number of transmission systems in units of the block composed of the data to be transmitted, and the MIMO block number Let the number of symbols be a MIMO block number, let the number of symbols of the data to be transmitted be the number of data symbols b, let the number of symbols of the pilot signal be the number of pilot signal symbols c, and let the number of the plurality of transmitting antennas be MIMO The number of transmissions is d, the number of symbols in the MIMO detection range to be equalized in the frequency domain is the number of MIMO detection range symbols SS, and the MIMO detection range is the MIMO block included in the first block in the detection target block. The pilot signal inserting portion is included in the detection target block in the plurality of transmission systems as a range from the number to the first pilot signal included in the first block in the detection target block next to the detection target block. When a matrix is configured with the two consecutive pilot signals as one element, null data elements are arranged on the diagonal of the matrix (A), and among all the pilot signals that make up the matrix, The pilot signals other than the null data arranged on the diagonal line are two consecutive UWs (unique words) consisting of known fixed pattern signals (B), and the number of pilot signal symbols c is a power of 2. Yes (C), the MIMO detection range symbol number SS is a power of 2, and is represented by a formula: SS = (a + b) x d + c x (2 x d-1) (D), and the detection target The two consecutive pilot signals are inserted at predetermined positions so as to satisfy the condition (E) that the two consecutive pilot signals contained in the first block of the blocks are the same, and the detection target is detected. It is characterized by generating a block symbol sequence.

Furthermore, the single-carrier MIMO receiving apparatus of claim 3 comprises a single or multiple receiving antennas, and transmits modulated waves transmitted from multiple transmitting antennas provided in the single-carrier MIMO transmitting apparatus to the single or multiple receiving antennas. Estimate the MIMO channel based on the received pilot signal included in the received signal received by one or more receiving systems corresponding to the MIMO SC-FDE block multiplexed, and perform equalization in the frequency domain. In the single-carrier MIMO receiving apparatus that performs is the number of data symbols b, the number of symbols of the pilot signal is the number of pilot signal symbols c, the number of the plurality of transmitting antennas is the number of MIMO transmissions d, and the symbols in the MIMO detection range to be equalized in the frequency domain. is the number of MIMO detection range symbols SS, the detection target block is composed of the same number of blocks as the MIMO transmission number d, and the MIMO detection range is the MIMO detection range included in the first block in the detection target block. The range from the MIMO block number to the leading pilot signal included in the first block in the detection target block next to the detection target block, and included in the detection target block in the plurality of transmission systems of the single-carrier MIMO transmission device When a matrix is configured with the two continuous pilot signals as one element, two continuous UW (unique word) elements consisting of known fixed pattern signals are arranged on the diagonal of the matrix (A), among all the pilot signals constituting the matrix, the pilot signals other than the two consecutive UWs arranged on the diagonal line are null data (B), and the number of pilot signal symbols c is is a power of 2 (C), the MIMO detection range symbol number SS is a power of 2, and is represented by the formula: SS = (a + b) x d + c x (2 x d-1) (D), and , assuming that the two consecutive pilot signals included in the first block in the detection target block are the same (E), fast Fourier transform the pilot signals, estimate the MIMO channel, A MIMO channel estimator for each receiving system that performs upsampling of the MIMO channel so as to match the MIMO detection range symbol count SS and outputs the MIMO channel after upsampling; and a preset MIMO detection range symbol count. A Fourier transform unit for each receiving system that fast Fourier transforms the MIMO detection range corresponding to SS and outputs a frequency domain signal, and the MIMO channel after upsampling output by the MIMO channel estimating unit for each receiving system. , and the frequency domain signal output by the Fourier transform unit for each receiving system, and the MIMO channel after upsampling corresponding to the preset MIMO detection range symbol number SS and the frequency domain a frequency domain MIMO channel equalization unit that performs MIMO channel equalization in the frequency domain using a signal, wherein the MIMO channel estimation unit configures the detection target block from the signal received by the receiving system. extracting the received pilot signals included in the same number of the blocks as the number d of MIMO transmissions, fast Fourier transforming the received pilot signals, and converting the result of the fast Fourier transform of the received pilot signals into the time domain UW fast It is characterized by estimating a channel response between each of the plurality of transmitting antennas and the receiving antenna of the receiving system by dividing by the Fourier transform result.

Further, the single-carrier MIMO receiver of claim 4 comprises a single or a plurality of receiving antennas, and transmits modulated waves transmitted from a plurality of transmitting antennas provided in the single-carrier MIMO transmitting device to the single or a plurality of receiving antennas. Estimate the MIMO channel based on the received pilot signal included in the received signal received by one or more receiving systems corresponding to the MIMO SC-FDE block multiplexed, and perform equalization in the frequency domain. In the single-carrier MIMO receiving apparatus that performs is the number of data symbols b, the number of symbols of the pilot signal is the number of pilot signal symbols c, the number of the plurality of transmitting antennas is the number of MIMO transmissions d, and the symbols in the MIMO detection range to be equalized in the frequency domain. is the number of MIMO detection range symbols SS, the detection target block is composed of the same number of blocks as the MIMO transmission number d, and the MIMO detection range is the MIMO detection range included in the first block in the detection target block. The range from the MIMO block number to the leading pilot signal included in the first block in the detection target block next to the detection target block, and included in the detection target block in the plurality of transmission systems of the single-carrier MIMO transmission device When a matrix is configured with the two consecutive pilot signals as one element, null data elements are arranged on the diagonal of the matrix (A), and among all the pilot signals that make up the matrix , the pilot signals other than the null data arranged on the diagonal line are two consecutive UWs (unique words) consisting of known fixed pattern signals (B), and the number of pilot signal symbols c is a power of 2. (C), the MIMO detection range symbol number SS is a power of 2 and is represented by the formula: SS=(a+b)×d+c×(2×d−1) (D), and the detection Assuming that the two consecutive pilot signals contained in the first block in the target block are the same (E), fast Fourier transform the pilot signals, estimate the MIMO channel, and set the preset MIMO detection range. A MIMO channel estimator for each receiving system that performs upsampling of the MIMO channel so as to match the number of symbols SS, and outputs the MIMO channel after upsampling, and the preset MIMO detection range symbol number SS. a Fourier transform unit for each receiving system that fast Fourier transforms the MIMO detection range and outputs a frequency domain signal; a MIMO channel after upsampling output by the MIMO channel estimator for each receiving system; The frequency domain signals output by the Fourier transform unit for each receiving system are input, and the up-sampled MIMO channel and the frequency domain signal corresponding to the preset MIMO detection range symbol number SS are used. and a frequency domain MIMO channel equalization unit that performs MIMO channel equalization in the frequency domain, wherein the MIMO channel estimation unit configures the detection target block from the signal received by the receiving system. extracting the received pilot signals contained in the same number of blocks as the number of transmissions d, fast Fourier transforming the received pilot signals of the same number as the number of MIMO transmissions d, fast Fourier transforming the received pilot signals, and A channel response between each of the plurality of transmitting antennas and the receiving antenna of the receiving system is estimated based on the UW fast Fourier transform result in the time domain.

As described above, according to the present invention, transmission efficiency can be improved when performing MIMO transmission using the SC-FDE scheme.

1 is a block diagram showing a schematic configuration of a single-carrier MIMO transmission device according to an embodiment of the present invention; FIG. FIG. 4 is a diagram showing a symbol block configuration example of the MIMO SC-FDE scheme when the number of transmissions is 2 in the embodiment of the present invention; FIG. 4 is a diagram showing a symbol block configuration example (an example of a UW diagonal structure) of the MIMO SC-FDE scheme when the number of transmissions is 4 in the embodiment of the present invention; FIG. 4 is a diagram showing a symbol block configuration example (null data diagonal structure example) of the MIMO SC-FDE scheme when the number of transmissions is 4 in the embodiment of the present invention; 1 is a block diagram showing a schematic configuration of a single carrier MIMO receiver according to an embodiment of the present invention; FIG. 4 is a block diagram showing a schematic configuration of a reception processing unit; FIG. FIG. 10 is a diagram illustrating an example of channel estimation processing; It is a figure which compares the symbol block structure example of a prior art and embodiment of this invention. 1 is a diagram showing a symbol block configuration of a null structure of a MIMO SC-FDE scheme in the prior art; FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated in detail using drawing. The single-carrier MIMO transmission apparatus of the present invention performs MIMO allocation on the encoded bit sequence of data to be transmitted, and UW or null data, which is a pilot signal, is arranged diagonally in the block configuration of a plurality of transmission signals. The symbol block of the MIMO SC-FDE scheme is configured so as to satisfy conditions (A), (B), (C), (D), and (E) described later.

Further, in the single-carrier MIMO receiver of the present invention, UW or null data, which are pilot signals included in the received signal, are arranged diagonally in the block configuration of a plurality of transmitted signals (A) and (B) described later. , (C), (D) and (E) are used to estimate the MIMO channel, and MIMO detection is performed on the MIMO detection range that satisfies the condition (D) described later. and

As a result, the UW can be used as a CP in the transmission signal, and there is no need to insert the latter part of the data as the CP. Therefore, transmission by the MIMO SC-FDE scheme becomes possible without adding individual CPs, and data efficiency can be improved as compared with the conventional technology. Therefore, transmission efficiency can be improved when performing MIMO transmission using the SC-FDE scheme.

In addition, since the power of the pilot signal is not biased among the transmission signals, it is possible to estimate the MIMO channel without bias in accuracy among the transmission signals on the receiving side.

Hereinafter, embodiments of the present invention will be described with an example of a 2-transmission and 2-reception MIMO SC-FDE scheme in which the number of transmissions and the number of receptions are respectively 2, but the number of transmissions and the number of receptions can be increased. It is also possible to set the number of receptions to one.

[Single carrier MIMO transmission device]
First, a single carrier MIMO transmission apparatus according to an embodiment of the present invention will be explained. FIG. 1 is a block diagram showing a schematic configuration of a single-carrier MIMO transmission apparatus according to an embodiment of the invention.

This transmitting device (single-carrier MIMO transmitting device) 1 generates a signal that enables MIMO detection in the frequency domain by a receiving device shown in FIG. ) to wirelessly transmit information.

This transmission device 1 includes a transmission preprocessing unit 10, an intersystem distribution unit 11, inner interleaving units 12-1 and 12-2, mapping units 13-1 and 13-2, MIMO block number insertion units 14-1 and 14- 2, pilot signal insertion units 15-1, 15-2, band-limiting filter units 16-1, 16-2, digital quadrature modulation units 17-1, 17-2, DA conversion units 18-1, 18-2, transmission It has high frequency sections 19-1 and 19-2 and transmission antennas 20-1 and 20-2.

A transmission preprocessing unit 10 performs preprocessing such as energy diffusion processing, error correction coding processing, and interleaving processing on an information bit sequence to be transmitted (data to be transmitted) to generate a coded bit sequence, The encoded bit sequence is output to inter-system distribution section 11 . Arbitrary energy diffusion processing, error correction coding processing, interleaving processing, and the like can be applied to this preprocessing.

The inter-system allocation unit 11 receives the encoded bit sequence from the transmission preprocessing unit 10, performs bit allocation on the encoded bit sequence to two transmission systems, and distributes the encoded bit sequence after the bit allocation. It is output to interleaving sections 12-1 and 12-2. This bit distribution is performed according to the number of transmissions, and if it corresponds to the reverse distribution on the receiving side, it can be distributed in any pattern.

Hereinafter, interleaving section 12-1, mapping section 13-1, MIMO block number inserting section 14-1, pilot signal inserting section 15-1, band limiting filter section 16-1, digital quadrature modulation section in the first transmission system 17-1, DA conversion unit 18-1, high frequency transmission unit 19-1 and transmission antenna 20-1 will be described, but interleaving unit 12-2, mapping unit 13-2, MIMO block number Insertion section 14-2, pilot signal insertion section 15-2, band-limiting filter section 16-2, digital quadrature modulation section 17-2, DA conversion section 18-2, transmission high-frequency section 19-2, and transmission antenna 20-2 The same is true for

The inner interleaving unit 12-1 receives the coded bit sequence after bit distribution from the inter-system distribution unit 11, and performs inner interleaving processing such as bit interleaving and time interleaving on the coded bit sequence after bit distribution. . Inner interleaving section 12-1 then outputs the coded bit sequence after inner interleaving to mapping section 13-1.

The mapping unit 13-1 receives the inner-interleaved coded bit sequence from the inner interleaver 12-1, and applies a predetermined modulation scheme such as QPSK, 16QAM, 16APSK, etc. to the inner-interleaved coded bit sequence. to do the mapping. Mapping section 13-1 then outputs the bit sequence after mapping to MIMO block number inserting section 14-1.

MIMO block number inserting section 14-1 receives the bit sequence after mapping from mapping section 13-1, and inserts a MIMO block number (MIMO block number symbol) at a predetermined position in the bit sequence after mapping. Then, MIMO block number inserting section 14-1 outputs the symbol sequence in which the MIMO block number is inserted to pilot signal inserting section 15-1.

Here, the MIMO block number inserting unit 14-1 inserts a value for identifying the MIMO block number into the bit sequence after mapping, and inserts a value for identifying the MIMO block number into the MIMO block by modulation processing. Generate as a number symbol. Specifically, the MIMO block number inserting unit 14-1 modulates a value identifying the MIMO block number by a differential modulation method such as DBPSK or DQPSK to generate a MIMO block number symbol.

Examples of MIMO block numbers are 0 and 1 when the number of transmissions is two. Also, when the number of transmissions is 4, it is 00, 01, 10, 11. The MIMO block number inserting unit 14-1 may perform encoding processing that enables error correction coding or error detection on the MIMO block number.

Pilot signal inserting section 15-1 receives as input the symbol sequence into which the MIMO block number is inserted from MIMO block number inserting section 14-1. Then, pilot signal inserting section 15-1 inserts two consecutive pilot signals at predetermined positions in the symbol sequence in which the MIMO block number is inserted. Specifically, the pilot signal inserting unit 15-1 uses the transmission signals (symbol sequences) of the same number of blocks as the number of transmissions as a unit such that two consecutive UWs are arranged diagonally in a block configuration. , or a predetermined pilot signal consisting of UW and null data is inserted at a predetermined position so as to form a block configuration in which the null data are arranged diagonally.

For example, in the example of FIG. 2, which will be described later, the pilot signal insertion unit 15-1 has a block configuration in which two consecutive UWs are arranged diagonally in the transmission signals x ₁ and x ₂ of the same number of blocks as the number of transmissions of 2. UW and null data pilot signals are inserted at predetermined positions so that In this case, in the transmission signals x ₁ and x ₂ of the same number of blocks as the transmission number 2, the block configuration in which two consecutive UWs are arranged diagonally is also the block configuration in which null data is arranged diagonally.

Pilot signal insertion section 15-1 generates a symbol sequence in which two consecutive pilot signals are inserted as a symbol sequence of the MIMO SC-FDE block, and outputs this to band-limiting filter section 16-1.

Here, the predetermined pilot signal is a pilot signal set in advance so as to satisfy the following conditions (A) to (E).
(A) In the block configuration of the transmission signal consisting of the same number of blocks as the number of transmissions, two consecutive UWs or null data are arranged on a diagonal line (UW diagonal structure or null data diagonal structure) . The condition (A) is that two continuous pilot signals included in detection target blocks (see α in FIGS. 2, 3 and 4 to be described later) in a plurality of transmission systems provided in the transmission device 1 are combined into one When constructing a matrix as elements, it means that two consecutive UW elements or null data elements are arranged on the diagonal of the matrix. For example, in the example of FIG. 3, the two consecutive UW elements arranged on the diagonal of the matrix are the first row, first column, second row, second column, third row, third column and fourth row, fourth column of the matrix. refers to an element of

(B) When a plurality of pilot signals included in the block configuration of the transmission signal consisting of the same number of blocks as the number of transmissions are composed of UWs and null data, and the UWs are arranged diagonally under the condition (A) above , the other pilot signals are null data, and when null data are arranged on the diagonal line, the other pilot signals are UW.

(C) The number of pilot signal symbols (the number of pilot signal symbols c) is a power of two.
(D) The number of symbols in the MIMO detection range where MIMO channel equalization is performed in the frequency domain (the number of symbols in the MIMO detection range, the number of symbols to be equalized) SS is a power of 2 and is represented by the following equation matter.
[Number 1]
SS=(a+b)×d+c×(2×d−1) (1)
Let a be the number of MIMO block number symbols, b be the number of data symbols, c be the number of pilot signal symbols, and d be the number of transmissions (the number of MIMO transmissions, the number of transmission antennas, and the number of transmission systems).

Here, the MIMO SC-FDE block consists of two consecutive pilot signal sequences, a MIMO block number symbol sequence and a data symbol sequence, and is a detection target block (see α in FIGS. 2, 3 and 4 described later) consists of the same number of MIMO SC-FDE blocks as the number of transmissions d. That is, the pilot signal inserting section 15-1 generates detection target blocks in units of MIMO SC-FDE blocks.

The MIMO detection range is a range from the MIMO block number included in the first block in the detection target block to the leading pilot signal included in the first block in the detection target block next to the detection target block. That is, the MIMO detection range includes the MIMO block number symbol sequence, data symbol sequence, pilot signal sequence, pilot signal sequence, MIMO block number symbol sequence, data symbol sequence, ..., MIMO block number symbol sequence, data symbol sequence and pilots. signal sequence.

(E) Two consecutive pilot signals included in the first block in the detection target block are the same. For example, in FIGS. 2, 3 and 4, which will be described later, the first block contains two consecutive UWs.

Thus, by satisfying the conditions (A) and (B) described above, UWs or null data can be evenly arranged between transmission signals. As a result, the power of the pilot signals is uniform among the transmission signals and is not biased among the transmission signals. Even reception performance can be obtained between them.

Further, by satisfying the above condition (C), the pilot signal can be subjected to fast Fourier transform, and the MIMO channel can be estimated on the receiving side.

Further, by satisfying the above condition (D), signals in the MIMO detection range can be subjected to fast Fourier transform and inverse fast Fourier transform, and MIMO channel equalization can be performed on the receiving side. , the data can be decrypted.

Furthermore, by satisfying the condition (E) described above, the last (second) UW of two consecutive UWs in the first block also serves as the CP, so there is no need to insert the CP into the block. As a result, the transmission efficiency can be improved, and the processing load can be reduced because there is no need to handle CPs.

FIG. 2 is a diagram showing a symbol block configuration example of the MIMO SC-FDE scheme when the number of transmissions is 2 in the embodiment of the present invention. Transmission signals x ₁ and x ₂ represent signals transmitted from the first and second transmission systems in the transmission device 1, respectively.

Pilot signals are UW and null data. UW is a known fixed pattern signal between transmission and reception, as explained in FIG. is used.

The transmission signals x ₁ and x ₂ are configured in units of two blocks, the first block being a MIMO odd block and the second block being a MIMO even block. These two blocks form a detection target block α, and MIMO detection is performed on the receiving side using this as a unit.

The first block of the transmitted signal x ₁ consists of two consecutive UWs, a MIMO block number and data (DATA1 _t0 ). The first block of the transmitted signal x ₂ is composed of the same number of symbols of null data, MIMO block number, and data (DATA2 _t0 ) as two consecutive UWs.

The second block of the transmitted signal x ₁ consists of the same number of symbols of null data, MIMO block number and data (DATA1 _t1 ) as two consecutive UWs. The second block of the transmitted signal x ₂ consists of two consecutive UWs, the MIMO block number and data (DATA2 _t1 ).

Regarding the transmission signal x ₁ , the last (second) UW of the two consecutive UWs in the first block included in the detection target block α is the two consecutive UWs in the first block included in the next detection target block. It is the same as the first (first) UW among the UWs to be used, and also serves as CP in the MIMO detection range. That is, for the transmitted signal x ₁ , the first block contains two consecutive UWs, and the latter UW of the two consecutive UWs has the latter part of the MIMO detection range inserted as CP It can be said that it is GI.

The transmission signal _x2 has the same configuration as the transmission signal _x1 shifted by one block. Therefore, it can be said that the last UW of two consecutive UWs in the transmission signal _x2 is also the GI inserted as the CP.

As a result, it is not necessary to insert the portion behind the MIMO detection range as CP, so that the transmission efficiency can be improved and the processing load can be reduced.

In FIG. 2, from the above conditions (C) and (D), the number of transmissions d = 2, the number of MIMO block number symbols a = 2, and the number of pilot signal symbols c = 2 ⁸ = 256, the number of data symbols b=1662 and the MIMO detection range is 2 ¹² =4096.

Note that the number of pilot signal symbols c is actually the number of symbols corresponding to the GI length in the OFDM system, which is set according to the maximum delay time for delayed waves to arrive. The symbol length of the pilot signal is obtained from the number of symbols and the symbol rate, and is set so as not to exceed the maximum delay time.

In this way, as shown in FIG. 2, the pilot signal inserting unit 15-1 arranges two consecutive UWs diagonally in the transmission signals x ₁ and x ₂ of the same number of blocks as the number of transmissions of 2. The UW and null data pilot signals are inserted at the positions shown in FIG. 2 so as to form a block structure.

FIG. 3 is a diagram showing a symbol block configuration example (example of UW diagonal structure) of the MIMO SC-FDE scheme when the number of transmissions is 4 in the embodiment of the present invention. shows an example of placement in Transmission signals x ₁ , x ₂ , x ₃ , x ₄ represent signals transmitted from the first, second, third and fourth transmission systems in the transmission device 1, respectively. Pilot signals are UW and null data.

The transmission signals x ₁ , x ₂ , x ₃ , and x ₄ are configured in units of four blocks from first to fourth. These four blocks form a detection target block α, and MIMO detection is performed on the receiving side using this as a unit.

The first block of the transmitted signal x ₁ consists of two consecutive UWs, a MIMO block number and data (DATA1 _t0 ). The first block of the transmission signals x ₂ , x ₃ , x ₄ is composed of the same number of symbols of null data, MIMO block number, and data (DATA2 _t0 , DATA3 _t0 , DATA4 _t0 ) as two consecutive UWs.

The second block of the transmitted signal x ₂ consists of two consecutive UWs, the MIMO block number and data (DATA2 _t1 ). The second block of the transmitted signals x ₁ , x ₃ , x ₄ consists of the same number of symbols of null data, MIMO block number and data (DATA1 _t1 , DATA3 _t1 , DATA4 _t1 ) as two consecutive UWs.

The third block of the transmitted signal x ₃ consists of two consecutive UWs, the MIMO block number and data (DATA3 _t2 ). The third block of the transmitted signals x ₁ , x ₂ , x ₄ consists of the same number of symbols of null data, MIMO block number, and data (DATA1 _t2 , DATA2 _t2 , DATA4 _t2 ) as two consecutive UWs.

The fourth block of the transmitted signal x ₄ consists of two consecutive UWs, the MIMO block number and data (DATA4 _t3 ). The fourth block of the transmitted signals x ₁ , x ₂ , x ₃ consists of the same number of symbols of null data, MIMO block number, and data (DATA1 _t3 , DATA2 _t3 , DATA3 _t3 ) as two consecutive UWs.

Regarding the transmission signal x ₁ , the last (second) UW of the two consecutive UWs in the first block included in the detection target block α is the two consecutive UWs in the first block included in the next detection target block. It is the same as the first (first) UW among the UWs to be used, and also serves as CP in the MIMO detection range. That is, for the transmitted signal x ₁ , the first block contains two consecutive UWs, and the latter UW of the two consecutive UWs has the latter part of the MIMO detection range inserted as CP It can be said that it is GI.

The transmission signal _x2 has the same configuration as when the transmission signal _x1 is shifted by one block, the transmission signal _x3 has the same configuration as when the transmission signal _x2 is shifted by one block, and the transmission signal _x4 is the same configuration as the case where the transmission signal _x3 is shifted by one block. Therefore, for the transmission signal x ₂ as well, it can be said that the last UW of the two consecutive UWs in the second block is the GI inserted as the CP. The same is true for the third block of transmitted signal _x3 and the fourth block of transmitted signal _x4 .

As a result, it is not necessary to insert the portion behind the MIMO detection range as CP, so that the transmission efficiency can be improved and the processing load can be reduced.

In FIG. 3, from the above conditions (C) and (D), the number of transmissions d = 4, the number of MIMO block number symbols a = 2, and the number of pilot signal symbols c = 2 ⁸ = 256, the number of data symbols b=1598 and the MIMO detection range is 2 ¹³ =8192.

In this way, as shown in FIG. 3, the pilot signal inserting unit 15-1, in the transmission signals x ₁ , x ₂ , x ₃ , x 4 of the same number of blocks as the number of transmissions of ₄ , has two consecutive UWs. The UW and null data pilot signals are inserted at the positions shown in FIG. 3 so as to provide a diagonal block configuration.

FIG. 4 is a diagram showing a symbol block configuration example (example of null data diagonal structure) of the MIMO SC-FDE scheme when the number of transmissions is 4 in the embodiment of the present invention. is shown. This symbol block configuration example uses the same number of symbols of null data instead of the two consecutive UWs shown in FIG.

As in FIG. 3, the transmission signals x ₁ , x ₂ , x ₃ , x ₄ are composed of four blocks from the first to fourth blocks. These four blocks form a detection target block α, and MIMO detection is performed on the receiving side using this as a unit.

The first block of the transmission signals x ₁ , x ₂ , x ₃ consists of two consecutive UWs, MIMO block number and data (DATA1 _t0 , DATA2 _t0 , DATA3 _t0 ). The first block of the transmitted signal x ₄ is composed of two consecutive UWs and the same number of symbols of null data, MIMO block number, and data (DATA4 _t0 ).

The second block of the transmitted signals x ₁ , x ₂ , x ₄ consists of two consecutive UWs, MIMO block number and data (DATA1 _t1 , DATA2 _t1 , DATA4 _t1 ). The second block of the transmitted signal _x3 consists of the same number of symbols of null data, MIMO block number and data (DATA3 _t1 ) as two consecutive UWs.

The third block of the transmitted signals x ₁ , x ₃ , x ₄ consists of two consecutive UWs, MIMO block number and data (DATA1 _t2 , DATA3 _t2 , DATA4 _t2 ). The third block of the transmitted signal x ₂ consists of the same number of symbols of null data, MIMO block number, and data (DATA2 _t2 ) as two consecutive UWs.

The fourth block of the transmitted signals x ₂ , x ₃ , x ₄ consists of two consecutive UWs, MIMO block number and data (DATA2 _t3 , DATA3 _t3 , DATA4 _t3 ). The fourth block of the transmitted signal x ₁ consists of the same number of symbols of null data, MIMO block number and data (DATA1 _t3 ) as two consecutive UWs.

Regarding the transmission signals x ₁ , x ₂ , and x ₃ , the last (second) UW of the two consecutive UWs in the first block included in the detection target block α is the first UW included in the next detection target block. is the same as the first (first) UW of two consecutive UWs in the block, and also serves as CP in the MIMO detection range. That is, for the transmission signals x ₁ , x ₂ , and x ₃ , the first block contains two consecutive UWs, and the latter UW of the two consecutive UWs is the rear portion of the MIMO detection range. is the GI inserted as CP.

The transmission signal _x2 has the same configuration as when the transmission signal _x1 is shifted by one block, the transmission signal _x3 has the same configuration as when the transmission signal _x2 is shifted by one block, and the transmission signal _x4 is the same configuration as the case where the transmission signal _x3 is shifted by one block. Therefore, for the second blocks of the transmission signals x ₁ , x ₂ , and x ₄ as well, it can be said that the last UW of the two consecutive UWs is the GI inserted as the CP. The same is true for the third block of transmitted signals x ₁ , x ₃ and x ₄ and the fourth block of transmitted signals x ₂ , x ₃ and x ₄ .

As a result, it is not necessary to insert the portion behind the MIMO detection range as CP, so that the transmission efficiency can be improved and the processing load can be reduced.

In FIG. 4, from the above conditions (C) and (D), the number of transmissions d = 4, the number of MIMO block number symbols a = 2, and the number of pilot signal symbols c = 2 ⁸ = 256, the number of data symbols b=1598 and the MIMO detection range is 2 ¹³ =8192.

In this way _, as shown in FIG _. 4, the pilot signal inserting unit 15-1 _uses two _consecutive UWs and UW and null data pilot signals are inserted at the positions shown in FIG. 4 so as to form a block structure in which the same number of symbols of null data are arranged on a diagonal line.

Also, as shown in FIGS. 3 and 4, the power of the pilot signals is uniform among the transmission signals, and there is no bias among the transmission signals.

Returning to FIG. 1, band-limiting filter section 16-1 receives as input the symbol sequence of the MIMO SC-FDE block from pilot signal inserting section 15-1. Then, the band-limiting filter section 16-1 performs double up-sampling on the symbol sequence of the MIMO SC-FDE block, and performs waveform shaping by band-limiting filter processing. The band-limiting filter section 16-1 outputs the waveform-shaped symbol sequence of the MIMO SC-FDE block to the digital quadrature modulation section 17-1. A root roll-off filter is generally used as the band-limiting filter.

Digital quadrature modulation section 17-1 receives as input the symbol sequence of the MIMO SC-FDE block after waveform shaping from band-limiting filter section 16-1. Then, the digital quadrature modulation section 17-1 performs digital quadrature modulation processing on the symbol sequence of the MIMO SC-FDE block after waveform shaping.

Further, the digital quadrature modulation section 17-1 performs aperture correction for correcting the aperture effect due to the digital/analog conversion in the DA conversion section 18-1. The digital quadrature modulation section 17-1 outputs the quadrature-modulated signal to the DA conversion section 18-1.

The DA converter 18-1 receives the quadrature-modulated signal from the digital quadrature modulator 17-1, converts the quadrature-modulated digital signal into an analog signal, and converts the analog signal to a transmission high-frequency section 19-1. output to

The transmission high-frequency unit 19-1 receives the analog signal from the DA conversion unit 18-1, converts the frequency of the analog signal to a radio frequency, amplifies it to a specified power with a power amplifier, and transmits the signal to the transmission antenna 20-1. 1 transmits a modulated wave.

As described above, according to the transmitting apparatus 1 of the embodiment of the present invention, the pilot signal inserting section 15-1 inserts two consecutive blocks of transmission signals of the same number of blocks as the number of transmissions for a symbol sequence. The above-mentioned (A), (B), (C), (D) and (E), such as a block configuration in which the UWs are arranged diagonally, or a block configuration in which null data is arranged diagonally. A MIMO SC-FDE block is generated by inserting two consecutive pilot signals to satisfy the conditions.

Then, from the transmitter 1, the pilot signals satisfying the conditions (A), (B), (C), (D), and (E) described above, that is, the transmission signals of the same number of blocks as the number of transmissions, are transmitted diagonally. A modulated wave is transmitted that includes two consecutive UW or null data pilot signals placed at .

FIG. 8 is a diagram comparing symbol block configuration examples in the prior art and the embodiment of the present invention. FIG. 8(1) shows a symbol block configuration example when the number of transmissions is 2 in the prior art, and FIG. 8(2) shows a symbol block configuration example when the number of transmissions is 2 in the embodiment of the present invention. ing.

From FIGS. 8(1) and 8(2), in the prior art, the CP is inserted in the MIMO SC-FDE block, whereas in the embodiment of the present invention, the UW also serves as the CP, and the MIMO SC - It can be seen that no CP is inserted in the FDE block.

Thus, in the embodiment of the present invention, since the last (second) UW of two consecutive UWs in the first block also serves as the CP, it is necessary to insert the CP into the MIMO SC-FDE block individually. There is no

That is, since there is no need to insert a CP in each transmission system, the transmission efficiency can be improved and the processing load can be reduced.

Therefore, when performing MIMO transmission using the SC-FDE scheme, the ratio of effective data increases with respect to the total transmission signal, so when compared at the same symbol rate, the transmission rate is made higher than that of the conventional technology. can improve transmission efficiency.

A pilot signal is composed of UWs and null data. In the examples shown in FIGS. 2 and 3, two consecutive UWs are arranged on a diagonal line, and other pilot signals are null data. Also, in the example shown in FIG. 4, null data are arranged on the diagonal line, and the pilot signals other than this are UW.

As a result, since the power of the pilot signal is not biased among the transmission signals, it is possible to estimate a MIMO channel with no bias in accuracy among the transmission signals on the receiving side, and obtain uniform reception performance among the transmission signals. be able to.

[Single carrier MIMO receiver]
Next, a single carrier MIMO receiver according to an embodiment of the present invention will be explained. FIG. 5 is a block diagram showing a schematic configuration of a single carrier MIMO receiver according to an embodiment of the present invention.

This receiving device (single-carrier MIMO receiving device) 2 receives modulated waves transmitted from the plurality of transmitting antennas 20-1 and 20-2 of the transmitting device 1 shown in FIG. , 30-2) and performs MIMO detection (frequency-domain MIMO channel estimation and equalization).

The receiving device 2 includes receiving antennas 30-1, 30-2, reception processing units 40-1, 40-2, MIMO block number detection units 41-1, 41-2, MIMO block number comparison units 42-1, 42- 2, noise power detection units 43-1, 43-2, MIMO channel estimation units 44-1, 44-2, Fourier transform units 45-1, 45-2, frequency domain MIMO channel equalization unit 46, inverse Fourier transform unit 47-1, 47-2, symbol determination/likelihood calculation units 48-1, 48-2, post-equalization MIMO block number decoding units 49-1, 49-2, post-equalization MIMO block number determination unit 50, Deinterleaving units 51-1 and 51-2 and a decoding unit 52 are provided.

Hereinafter, the receiving antenna 30-1 of the first receiving system, the reception processing unit 40-1, the MIMO block number detection unit 41-1, the MIMO block number comparison unit 42-1, the noise power detection unit 43-1, the MIMO channel estimation Unit 44-1, Fourier transform unit 45-1, inverse Fourier transform unit 47-1, symbol determination/likelihood calculation unit 48-1, equalized MIMO block number decoding unit 49-1, and internal deinterleaving unit 51-1 will be described, but the reception antenna 30-2 of the second reception system, the reception processing unit 40-2, the MIMO block number detection unit 41-2, the MIMO block number comparison unit 42-2, the noise power detection unit 43-2, MIMO channel estimation unit 44-2, Fourier transform unit 45-2, inverse Fourier transform unit 47-2, symbol determination/likelihood calculation unit 48-2, equalized MIMO block number decoding unit 49-2 and inner deinterleaving unit The same is true for 51-2.

FIG. 6 is a block diagram showing a schematic configuration of the reception processing section 40-1. The reception processing section 40-1 includes a reception high frequency section 60, an AD conversion section 61, a digital quadrature demodulation section 62, a band limiting filter section 63 and a block synchronization section 64. FIG. The configuration of the reception processing unit 40-2 is also the same as that shown in FIG.

The high frequency receiving unit 60 amplifies the radio frequency signal received via the receiving antenna 30-1 to a desired power with a low phase noise amplifier, and then converts the radio frequency to an intermediate frequency. Then, the high frequency receiving section 60 outputs the intermediate frequency signal to the AD converting section 61 .

The AD converter 61 receives the intermediate frequency signal from the high frequency receiver 60 , converts the intermediate frequency analog signal into a digital signal, and outputs the digital signal to the digital quadrature demodulator 62 .

The digital quadrature demodulator 62 receives the digital signal from the AD converter 61, performs automatic frequency control on the digital signal, and generates a quadrature-demodulated complex baseband signal while correcting a frequency deviation. The digital quadrature demodulator 62 then outputs the frequency-corrected complex baseband signal to the band-limiting filter 63 .

The band-limiting filter unit 63 receives the frequency-corrected complex baseband signal from the digital quadrature demodulator 62 and performs band-limiting on the frequency-corrected complex baseband signal by filtering. Then, the band-limiting filter section 63 outputs the band-limited complex baseband signal to the block synchronization section 64 . A root roll-off filter is generally used as the band-limiting filter.

The block synchronization unit 64 receives the band-limited complex baseband signal from the band-limiting filter unit 63, and uses the IQ signal of the UW part as a reference for the band-limited complex baseband signal to perform a MIMO SC-FDE block. to detect the synchronization timing of Then, block synchronization section 64 outputs the MIMO SC-FDE block whose synchronization timing has been detected to MIMO block number detection section 41-1.

Returning to FIG. 5, the MIMO block number detection unit 41-1 receives the MIMO SC-FDE block whose synchronization timing is detected from the block synchronization unit 64 of the reception processing unit 40-1. Then, the MIMO block number detection unit 41-1 differentially demodulates the MIMO SC-FDE block by differential detection based on the synchronization timing position (synchronization position) detected by the block synchronization unit 64. Detect the MIMO block number.

The MIMO block number detection unit 41-1 outputs the MIMO block number to the MIMO block number comparison unit 42-1 and the MIMO channel estimation unit 44-1. Also, the MIMO block number detector 41-1 outputs the MIMO SC-FDE block to the noise power detector 43-1, the MIMO channel estimator 44-1 and the Fourier transform unit 45-1.

The MIMO block number comparison unit 42-1 receives the MIMO block number from the MIMO block number detection unit 41-1 and also receives the post-equalization MIMO block number from the post-equalization MIMO block number determination unit 50 described later. Then, MIMO block number comparing section 42-1 compares the MIMO block number with the equalized MIMO block number.

When the MIMO block number comparison unit 42-1 determines from the comparison result that the MIMO block number and the equalized MIMO block number match, the MIMO channel estimation unit 44 sends the comparison result and the MIMO block number indicating a match. Output to -1. On the other hand, when the MIMO block number comparison unit 42-1 determines that the MIMO block number and the equalized MIMO block number are different, the comparison result indicating the difference and the equalized MIMO block number are sent to the MIMO channel estimation unit 44-1. Output to 1.

As a result, when the MIMO block number and the equalized MIMO block number are different, the equalized MIMO block number input from the equalized MIMO block number determination unit 50 in the frequency domain MIMO channel equalization unit 46 to be described later is used as a reference. The MIMO channel estimator 44-1 is controlled so that MIMO detection is performed at .

The noise power detection unit 43-1 receives the MIMO SC-FDE block from the MIMO block number detection unit 41-1, measures the noise power n ₁ of the received signal using the MIMO SC-FDE block, and obtains the noise power n ₁ is output to the frequency domain MIMO channel equalization unit 46 .

The MIMO channel estimation unit 44-1 inputs the MIMO SC-FDE block and the MIMO block number from the MIMO block number detection unit 41-1, and the comparison result and the MIMO block number or equalization from the MIMO block number comparison unit 42-1. Then enter the MIMO block number.

MIMO channel estimator 44-1 performs MIMO channel estimator 44-1 for the MIMO SC-FDE block, based on the position of the synchronization timing detected by block synchronizer 64, according to the MIMO block number according to the comparison result or the equalized MIMO block number. Then, time-domain pilot signals included in a series of MIMO SC-FDE blocks (the same number of blocks as the number of transmissions constituting the block to be detected) are extracted, fast Fourier transform is performed, and the MIMO channel is estimated.

After estimating the MIMO channel, the MIMO channel estimator 44-1 matches the number of symbols (preset MIMO detection range symbol number SS) for which frequency domain equalization is performed by the subsequent frequency domain MIMO channel equalizer 46. Upsampling of the MIMO channel is performed as follows. Then, the MIMO channel estimator 44-1 outputs the up-sampled MIMO channel (for example, channel responses h ₁₁ and h ₁₂ when the number of transmissions is 2) to the frequency domain MIMO channel equalizer 46 . The MIMO channel after upsampling is a MIMO channel corresponding to the number of symbols for frequency domain equalization (preset MIMO detection range symbol number SS).

Here, the number of symbols of the MIMO channel before upsampling is the number of pilot signal symbols c under the condition (C) described above. The number of symbols of the MIMO channel after upsampling, that is, the number of symbols to be subjected to frequency domain equalization is the number of MIMO detection range symbols SS of the above equation (1) under the above condition (D). For example, if the number of transmissions is 2, the number of MIMO block number symbols a=2 and the number of pilot signal symbols c=2 ⁸ =256, the number of MIMO detection range symbols SS=2 ¹² =4096.

(Channel estimation when the number of transmissions is 2)
For example _, when the number of transmissions shown in FIG. A fast Fourier transform is performed on the pilot signals in the region (the first block pilot signal and the second block pilot signal) to estimate the channel responses h ₁₁ and h ₁₂ .

In addition, MIMO channel estimation section 44-2 generates _two time-domain pilot signals (first block pilot signal and the pilot signal of the second block) to estimate the channel responses h ₂₁ , h ₂₂ .

MIMO channel H when the number of transmissions is 2 is represented by the following equation.
[Number 2]

FIG. 7 is a diagram for explaining an example of channel estimation processing, and corresponds to the case where the number of transmissions shown in FIG. 2 is two. As described above, the received signal _y1 is the signal of the first receiving system, and the received signal _y2 is the signal of the second receiving system.

The MIMO channel estimators 44-1 and 44-2 estimate channel responses h ₁₁ , h ₁₂ , h ₂₁ and h ₂₂ for the same number of blocks as the number of transmissions 2 forming the detection target block.

The MIMO channel estimator 44-1, in the received signal y ₁ , is based on the position shifted by the FFT window offset from the end position of the last pilot signal (head position of the data signal) among the two consecutive pilot signals, The received pilot signal h ₁₁ UW _t of the first block and the received pilot signal h ₁₂ UW _t of the second block are extracted. UW _t denotes the time domain pilot signal.

Then, the MIMO channel estimation unit 44-1 fast Fourier transforms the extracted received pilot signal h ₁₁ UW _t and divides the fast Fourier transform result by the fast Fourier transform result UW _f of the pilot signal UW _t to obtain the channel Estimate the response h ₁₁ . Further, the MIMO channel estimation unit 44-1 fast Fourier transforms the extracted received pilot signal h ₁₂ UW _t and divides the fast Fourier transform result by the fast Fourier transform result UW _f of the pilot signal UW _t to obtain the channel Estimate the response h ₁₂ .

Similarly, in the received signal y ₂ , the MIMO channel estimation unit 44-2 is based on the position shifted by the FFT window offset from the end position of the latter pilot signal (head position of the data signal) of the two consecutive pilot signals. to extract the received pilot signal h ₂₁ UW _t of the first block and the received pilot signal h ₂₂ UW _t of the second block.

Then, the MIMO channel estimation unit 44-2 fast Fourier transforms the extracted received pilot signal h ₂₁ UW _t and divides the fast Fourier transform result by the fast Fourier transform result UW _f of the pilot signal UW _t to obtain the channel Estimate the response _h21 . Further, the MIMO channel estimation unit 44-2 fast Fourier transforms the extracted received pilot signal h ₂₂ UW _t and divides the fast Fourier transform result by the fast Fourier transform result UW _f of the pilot signal UW _t to obtain the channel Estimate the response _h22 .

An example of channel estimation processing shown in FIG. 7 will be described using mathematical formulas. The formula for 2×2 MIMO when the number of transmissions is 2 and the number of receptions (the number of MIMO receptions) is 2 is as follows. n ₁ and n ₂ are noise powers.
[Number 3]

It is assumed that the channel response h _nm is constant within two blocks to be MIMO separated, as shown in the following equation.
[Number 4]
h _nm =h _nm (t=0)=h _nm (t=1) (4)
t=0 indicates the first block and t=1 indicates the second block. n=1,2 and m=1,2.

Regarding the received signal _y1 of the first receiving system, the received signal _y1t=0 of the first block and the received signal _y1t=1 of the second block are represented by the following equations.
[Number 5]

This formula is transformed into the following formula.
[Number 6]

That is, the channel responses h ₁₁ and h ₁₂ are expressed by the following equations, ignoring the noise powers n _1t=0 and n _1t=1 .
[Number 7]

Thus, for the received signal y ₁ of the first receiving system, the channel responses h ₁₁ and h ₁₂ are obtained from the received signals y _1t=0 and y _1t=1 of the two consecutive blocks according to the above equation. .

For the received signal y ₂ of the second receiving system, the channel responses h ₂₁ and h ₂₂ are obtained from the received signals y _2t=0 and y _2t=1 of two consecutive blocks by the same formula as described above.

(Channel estimation when the number of transmissions is 4)
Next, channel estimation when the number of transmissions is 4 will be described. As described above, the symbol block configuration example of the MIMO SC-FDE scheme when the number of transmissions is 4 includes an example of a UW diagonal structure in which two consecutive UWs shown in FIG. 3 are arranged on a diagonal line, and There is an example of a null data diagonal structure in which the null data shown in FIG. 4 are arranged on a diagonal line. It is assumed that which diagonal structure is to be used is preset in the transmitting device 1 and the receiving device 2 .

Incidentally, if the pilot signal group having the UW diagonal structure or the null data diagonal structure is set in advance in the transmitting device 1 and the receiving device 2, the transmission signals x ₁ , x ₂ , x ₃ and x ₄ are rearranged. may have been For example, in FIG. 3, the pilot signal group of transmission signal _x1 and the pilot signal group of transmission signal _x2 may be exchanged. In this case, although the pilot signal group after replacement does not formally have a UW diagonal structure, by restoring the pilot signal group of the transmission signal _x1 and the pilot signal group of the transmission signal _x2 , the pilot signal The signal group has a UW diagonal structure.

That is, the diagonal here means that the pilot signal group is rearranged among the transmission signals x ₁ , x ₂ , x ₃ and x ₄ , and the diagonal relationship (UW diagonal structure or null data diagonal structure) means to be

In transmission signals x ₁ , x ₂ , x ₃ and x ₄ , it is assumed that pilot signals are extracted from each of the same number of blocks as the number of transmissions of 4, and a matrix consisting of pilot signal groups is constructed.

Assuming that two consecutive UWs are "1" and null data corresponding to two consecutive UWs is "0", in the case of the UW diagonal structure in FIG. 3, the pilot signal group is represented by the following matrix.
[Number 8]

Also, in the case of the null data diagonal structure of FIG. 4, the pilot signal group is represented by the following matrix.
[Number 9]

In the case of the UW diagonal structure in FIG. 3, the channel responses h ₁₁ , h ₁₂ , h ₁₃ , h _{14 ,} etc. are estimated by extending the channel estimation processing example shown in FIG.

Specifically, with the number of transmissions set to 4 and the number of receptions set to 4, the MIMO channel estimator 44-1 generates received pilot signals h ₁₁ UW _t and h ₁₂ UW of the first to fourth blocks in the received signal y ₁ . _t , h ₁₃ UW _t , h ₁₄ UW _t are extracted.

Then, the MIMO channel estimation unit 44-1 fast Fourier transforms each of the extracted received pilot signals h ₁₁ UW _t , h ₁₂ UW _t , h ₁₃ UW _t , and h ₁₄ UW _t , and converts each fast Fourier transform result to Channel responses h ₁₁ , h ₁₂ , h ₁₃ , h ₁₄ are estimated by dividing by the fast Fourier transform result UW _f of the pilot signal UW _t .

The MIMO channel estimator 44-2 performs the same processing as the MIMO channel estimator 44-1 on the received signal y ₂ to estimate channel responses h ₂₁ , h ₂₂ , h ₂₃ and h ₂₄ . Similarly, the MIMO channel estimator 44-3 estimates channel responses h ₃₁ , h ₃₂ , h ₃₃ , h ₃₄ from the received signal y ₃ , and the MIMO channel estimator 44-4 from the received signal y ₄ : Estimate the channel responses h ₄₁ , h ₄₂ , h ₄₃ , h ₄₄ .

In _the case of the null data diagonal structure _of FIG. 4 _, channel responses h ₁₁ , h ₁₂ , _{h 13 ,} h ₁₄ etc. are estimated.

That is, the MIMO channel estimator 44-1 or the like extracts the received pilot signals included in the same number of blocks as the number of transmissions 4 constituting the detection target block, fast Fourier transforms each of the four received pilot signals, and converts the four received pilot signals into four received pilot signals. Channel responses h ₁₁ , h ₁₂ , h ₁₃ , h ₁₄ , etc. are estimated based on the fast Fourier transform result of the pilot signal and the UW fast Fourier transform result in the time domain, as shown in equation (22) described later.

となる。 By the way, the condition for enabling channel estimation from the received signals y ₁ , y ₂ , y ₃ , y ₄ is that the order (rank) of this matrix is the same as the number of transmissions of 4, as shown in the following equation.
[Number 10]

becomes.

Even when the pilot signal group having the UW diagonal structure or the null data diagonal structure is rearranged among the transmission signals x ₁ , x ₂ , x ₃ and x ₄ , the rank of the matrix is 4, so the received signal From y ₁ , y ₂ , y ₃ , and y ₄ , conditions are satisfied that enable channel estimation.

Also, for example, in FIG. 4, only the pilot signals in the fourth block of the transmission signal _x2 , the third block of the transmission signal _x3 , and the second block of the transmission signal _x4 are null data, and the others are UW. Suppose there is.

［数１２］

The pilot signal group in this case is represented by the following matrix, and the rank is also 4.
[Number 11]

[number 12]

However, the power of the pilot signal is biased among the transmission signals x ₁ , x ₂ , x ₃ and x ₄ , and a MIMO channel with biased accuracy among the transmission signals x ₁ , x ₂ , x ₃ and x ₄ is estimated. As a result, the transmission performance deteriorates.

Therefore, the _condition for enabling channel estimation is that the matrix of the pilot signal group is the same as the _number of transmissions, that is, that there is no rank _drop . ₄ , the pilot signal group preferably has the UW diagonal structure of FIG. 3 or the null data diagonal structure of FIG.

An example of channel estimation processing when the number of transmissions is 4 and the number of receptions is 4 will be described below using mathematical expressions. The formula for 4×4 MIMO in this case is as follows. n ₁ , n ₂ , n ₃ , n ₄ are noise powers.
[Number 13]

It is assumed that the channel response h _nm is constant within the four blocks to be MIMO-separated, as shown in the following equation.
[Number 14]
h _nm =h _nm (t=0)=h _nm (t=1)=h _nm (t=2)=h _nm (t=3) (14)
t=0 indicates the first block, t=1 the second block, t=2 the third block, and t=3 the fourth block. n=1,2,3,4 and m=1,2,3,4.

(UW diagonal structure)
Next, channel estimation for the example of the UW diagonal structure with four transmissions shown in FIG. 3 will be described. For the received signal y ₁ of the first receiving system, the received signals y _1t=0 , y _1t=1 , y _1t=2 , y _1t=3 of four consecutive blocks are represented by the following equations.
[Number 15]

This formula is transformed into the following formula.
[Number 16]

That is, the channel responses h ₁₁ , h ₁₂ , h ₁₃ , h ₁₄ are expressed by the following equations, ignoring noise powers n _1t=0 , n _1t=1 , n _1t=2 , n _1t=3 .
[Number 17]

Thus _, for _the received signal y ₁ , _the channel responses h ₁₁ , _{h 12} , h ₁₃ , h ₁₄ are found.

For _the received _signal y _{2 ,} channel responses h ₂₁ , _{h 22} , h ₂₃ , h ₂₄ are determined. For the received signal y ₃ , _the channel response h _{31 , h 31} , h ₃₂ , h ₃₃ and h ₃₄ are obtained. For the received _signal y ₄ , _channel responses h _{41 ,} h ₄₁ , h ₄₂ , h ₄₃ and h ₄₄ are obtained.

(null data diagonal structure)
Next, channel estimation in the example of null data diagonal structure with four transmissions shown in FIG. 4 will be described. For the received signal y ₁ of the first receiving system, the received signals y _1t=0 , y _1t=1 , y _1t=2 , y _1t=3 of four consecutive blocks are represented by the following equations.
[Number 18]

［数２０］

This formula is transformed into the following formula.
[Number 19]

[number 20]

That is, the channel responses h ₁₁ , h ₁₂ , h ₁₃ and h ₁₄ are represented by the following equations.
[number 21]

Channel responses h ₁₁ , h ₁₂ , h ₁₃ , and h ₁₄ are expressed by the following equations, ignoring noise powers n _1t=0 , n _1t=1 , n _1t=2 and n _1t=3 .
[number 22]

Thus _, for _the received signal y ₁ , _the channel responses h ₁₁ , _{h 12} , h ₁₃ , h ₁₄ are found.

For _the received _signal y _{2 ,} channel responses h ₂₁ , _{h 22} , h ₂₃ , h ₂₄ are determined. For the received signal y ₃ , _{the channel} response h ₃₁ , _{h 31} , h ₃₂ , h ₃₃ and h ₃₄ are obtained. For the received _signal y ₄ , _channel responses h _{41 , h 41} , h ₄₂ , h ₄₃ and h ₄₄ are obtained.

In addition, comparing the above equation (17) showing the channel estimation process with the UW diagonal structure and the above equation (22) showing the channel estimation process with the null data diagonal structure, it can be seen that the channel estimation process with the UW diagonal structure is the null data The processing load is less than that of channel estimation processing with a diagonal structure.

On the other hand, from FIGS. 3 and 4, the reception frequency of pilot signals is higher in the null data diagonal structure than in the UW diagonal structure. Therefore, the block synchronization timing detection accuracy in the above-described reception processing unit 40-1 and the like is higher in the null data diagonal structure than in the UW diagonal structure.

Returning to FIG. 5, the Fourier transform unit 45-1 receives the MIMO SC-FDE block from the MIMO block number detection unit 41-1. Then, the Fourier transform unit 45-1 calculates the number of symbols (preset MIMO detection range symbols SS) corresponding to the time domain MIMO block number symbol sequence, data symbol sequence, pilot signal sequence, pilot signal sequence, MIMO block number symbol sequence, data symbol sequence, ..., MIMO block number symbol sequence, data symbol sequence and pilot signal sequences are shifted by the same amount as the FFT window offset of the MIMO channel estimation unit 44-1 and extracted, and these symbol sequences are fast Fourier transformed into the frequency domain.

The Fourier transform unit 45 - 1 outputs a frequency domain signal (for example, when the number of transmissions is 2, a frequency domain signal r ₁ (f)) to the frequency domain MIMO channel equalization unit 46 .

Here, the number of symbols for which frequency domain equalization is performed is the number SS of MIMO detection range symbols in the above equation (1) under the above condition (D).

For _example , when the number of transmissions shown in FIG. The time domain MIMO block number symbol sequence, data symbol sequence, pilot signal sequence, pilot signal sequence, MIMO block number symbol sequence, data symbol sequence and pilot signal sequence in the time domain corresponding to H.4096 are fast Fourier transformed into the frequency domain.

Here, for example, when the number of transmissions is 2, the noise power detector 43-2 obtains the noise power n ₂ , the MIMO channel estimator 44-2 obtains the channel responses h ₂₁ and h ₂₂ , the Fourier transform unit 45-2 obtains the frequency The domain signals r ₂ (f) are respectively output to the frequency domain MIMO channel equalization section 46 .

For example, when the number of transmissions is 2, the frequency domain MIMO channel equalization unit 46 receives the noise power n ₁ from the noise power detection unit 43-1 and the channel responses h ₁₁ and h ₁₂ from the MIMO channel estimation unit 44-1. is input, and the frequency domain signal r ₁ (f) is input from the Fourier transform unit 45-1. Further, the frequency domain MIMO channel equalization unit 46 receives the noise power n ₂ from the noise power detection unit 43-2, receives the channel responses h ₂₁ and h ₂₂ from the MIMO channel estimation unit 44-2, A signal r ₂ (f) in the frequency domain is input from the transform section 45-2.

The frequency domain MIMO channel equalization unit 46 performs noise power n ₁ , n ₂ , channel responses h ₁₁ , h ₁₂ , h ₂₁ , h ₂₂ and frequency domain signals r ₁ (f), r ₂ (f). , the transmitted signals x ₁ and x ₂ mixed with the frequency domain signals r ₁ (f) and r ₂ (f) are equalized using the zero forcing (ZF) criterion or the minimum mean squared error (MMSE) criterion or the like. (To separate.

That is, the frequency domain MIMO channel equalization unit 46 sets the MIMO channel H corresponding to the number of symbols for frequency domain equalization (preset MIMO detection range symbol number SS) and the number of symbols for frequency domain equalization (preset MIMO block number symbol sequence, data symbol sequence, pilot signal sequence, pilot signal sequence, MIMO block number symbol sequence, data symbol sequence, . The number symbol sequence, data symbol sequence and pilot signal sequence (and noise power) are used to equalize the mixed transmitted signals x ₁ and x ₂ .

The frequency domain MIMO channel equalization unit 46 outputs the equalized frequency domain signal x ₁ ^(f) corresponding to the transmission signal x 1 to the inverse Fourier transform unit 47-1, and also outputs the signal x ₁ ^(f) in the frequency domain corresponding to the transmission signal x ₂ . The equalized frequency domain signal x ₂ ^(f) is output to the inverse Fourier transform unit 47-2.

For example, when using the zero-forcing criterion, the frequency domain MIMO channel equalization unit 46 generates the MIMO channel H (channel responses h ₁₁ , h ₁₂ , h ₂₁ , h ₂₂ ) and the frequency domain signal r(f) (r ₁ (f ), r ₂ (f)), MIMO channel equalization is performed according to the following equation, and the equalized frequency domain signals x^(f) (x ₁ ^(f), x ₂ ^(f )).
[Number 23]

送信数をＮ_t、受信数をＮ_r、Ｎ_r次単位行列をＩ_Nrとする。 Also, when using the minimum mean squared error criterion, the frequency domain MIMO channel equalization unit 46 calculates the noise power σ ² , the MIMO channel H (channel responses h ₁₁ , h ₁₂ , h ₂₁ , h ₂₂ ) and the frequency domain signal r Based on (f) (r ₁ (f), r ₂ (f)), MIMO channel equalization is performed using the following equation, and the equalized frequency domain signal x^(f) (x ₁ ^( f), x ₂ ^(f)). The noise power σ ² is calculated based on the noise powers n ₁ and n ₂ .
[Number 24]

Let N _t be the number of transmissions, N _r be the number of receptions, and I _Nr be the N _r -order identity matrix.

Here, the signal r(f) in the frequency domain is represented by the following equation.
[number 25]

The frequency domain signal x^(f) after equalization is expressed by the following equation.
[Number 26]

The inverse Fourier transform unit 47-1 receives the equalized frequency domain signal x ₁ ^(f) corresponding to the transmission signal x ₁ from the frequency domain MIMO channel equalization unit 46, and is converted into the time domain _{, and the time domain signal corresponding to the transmission signal x 1 is} output to the symbol determination/likelihood calculation section 48-1.

The frequency domain signal after equalization corresponding to the transmission signal x ₁ is a frequency domain MIMO block number symbol sequence corresponding to the number of symbols subjected to frequency domain equalization (preset MIMO detection range symbol number SS). , data symbol sequence, pilot signal sequence, pilot signal sequence, MIMO block number symbol sequence, data symbol sequence, . . . , MIMO block number symbol sequence, data symbol sequence and pilot signal sequence.

In addition, the time domain signal corresponding to the transmission signal x ₁ is a time domain MIMO block number symbol sequence corresponding to the number of symbols subjected to frequency domain equalization (preset MIMO detection range symbol number SS), data A symbol sequence, a pilot signal sequence, a pilot signal sequence, a MIMO block number symbol sequence, a data symbol sequence, . . . , a MIMO block number symbol sequence, a data symbol sequence and a pilot signal sequence.

The symbol determination/likelihood calculation unit 48-1 receives the time domain signal corresponding to the transmission signal x ₁ from the inverse Fourier transform unit 47-1, and from the time domain signal, MIMO block number symbol sequence and data symbol sequence. and perform demapping and likelihood calculation on these sequences.

Symbol determination/likelihood calculation section 48-1 outputs the metric sequence of transmission signal x ₁ corresponding to the MIMO block number symbol sequence to post-equalization MIMO block number decoding section 49-1. Further, the symbol decision/likelihood calculation unit 48-1 internally deinterleaves the metric sequence of the transmission signal x ₁ corresponding to the information bit sequence (data encoded for error correction) that constitutes the data symbol sequence. Output to the unit 51-1. A bit sequence after hard decision, likelihood, quantized likelihood, or the like can be used as the metric sequence.

The post-equalization MIMO block number decoding unit 49-1 receives as input the metric sequence of the transmission signal x ₁ corresponding to the MIMO block number symbol sequence from the symbol determination/likelihood calculation unit 48-1, and from the metric sequence, the MIMO block A value corresponding to the number is extracted and output to the equalized MIMO block number determining section 50 as the equalized MIMO block number corresponding to the transmission signal _x1 .

Equalized MIMO block number determining section 50 receives the equalized MIMO block number corresponding to transmission signal x ₁ from equalized MIMO block number decoding section 49-1, and equalizes MIMO block number decoding section 49. -2 to the post-equalization MIMO block number corresponding to the transmission signal x ₂ is input.

An equalized MIMO block number determination unit 50 compares these equalized MIMO block numbers, and if these equalized MIMO block numbers match, the equalized MIMO block number is sent to the MIMO block number comparison unit. Output to 42-1 and 42-2. On the other hand, if the equalized MIMO block numbers do not match, the equalized MIMO block number determination unit 50 shifts the synchronization positions of the block numbers back and forth, and then the MIMO block number detection units 41-1 and 41 For -2 etc., the processing after MIMO block number detection is redone.

Here, in MIMO block number comparison units 42-1 and 42-2, the MIMO block numbers input from MIMO block number detection units 41-1 and 41-2 and the MIMO block number input from post-equalization MIMO block number determination unit 50 are The MIMO channel H (channel responses h ₁₁ , h ₁₂ , h ₂₁ , h ₂₂ ) estimated by the MIMO channel estimation units 44-1 and 44-2 when the equalized MIMO block numbers do not match will be explained. .

When the MIMO block number and the post-equalization MIMO block number do not match, each element of the MIMO channel H estimated by the MIMO channel estimation units 44-1 and 44-2 is replaced. In the case of the example shown in FIG. 2, the channel responses _h11 and _h12 are interchanged, and the channel responses _h21 and _h22 are interchanged.

Therefore, when the MIMO channel estimation unit 44-1 receives a comparison result indicating a mismatch from the MIMO block number comparison unit 42-1, the estimated channel response h ₁₁ and the channel response h ₁₂ are switched and output. do. Further, when the MIMO channel estimation unit 44-2 receives a comparison result indicating a mismatch from the MIMO block number comparison unit 42-2, the estimated channel response h ₂₁ and the channel response h ₂₂ are switched and output. do. This allows successful MIMO channel estimation.

Note that the MIMO block number detection units 41-1 and 41-2 may suspend the detection processing for one block and restart it so as to detect a normal MIMO block number.

The inner deinterleaving unit 51-1 receives as input the metric sequence of the transmission signal x ₁ corresponding to the information bit sequence forming the data symbol sequence from the symbol decision/likelihood calculation unit 48-1, and for the metric sequence, Inverse processing of inner interleaving section _12-1 shown in FIG.

The decoding unit 52 receives the metric sequence of the inner deinterleaved transmission signal x ₁ from the inner deinterleaving unit 51-1, and receives the metric sequence of the inner deinterleaved transmission signal x ₂ from the inner deinterleaving unit 51-2. Enter Then, the decoding unit 52 performs processing to return these metric sequences to one sequence in a manner corresponding to the inter-system distribution unit 11 shown in FIG. Then, the decoding unit 52 performs deinterleaving processing, error correction decoding processing, energy despreading processing, etc. corresponding to the transmission preprocessing unit 10 shown in FIG. Outputs an information bit sequence.

As described above, according to the receiving device 2 of the embodiment of the present invention, the modulated wave transmitted from the transmitting device 1 shown in FIG. 1 is received. The MIMO channel estimator 44-1 extracts the received pilot signal h ₁₁ UW _t of the first block from the received signal y ₁ and fast Fourier transforms it, and converts the result of the fast Fourier transform into the result of the fast Fourier transform of the pilot signal UW _t . Estimate the channel response h ₁₁ by dividing by UW _f . Further, the MIMO channel estimator 44-1 extracts the received pilot signal h ₁₂ UW _t of the second block from the received signal y ₁ and fast Fourier transforms the result of the fast Fourier transform into the fast Fourier transform of the pilot signal UW _t . Estimate the channel response h ₁₂ by dividing by the transform result UW _f .

Similarly, the MIMO channel estimator 44-2 extracts the received pilot signal h ₂₁ UW _t of the first block from the received signal y ₂ , fast Fourier transforms it, and divides it by UW _f to obtain the channel response h ₂₁ presume. Also, the MIMO channel estimation unit 44-2 extracts the received pilot signal h ₂₂ UW _t of the second block from the received signal y ₂ , performs fast Fourier transform, and divides the transform result by UW _f to obtain the channel response h Estimate ₂₂ .

After estimating MIMO channel H (channel responses h ₁₁ , h ₁₂ , h ₂₁ , h ₂₂ ), MIMO channel estimation units 44-1 and 44-2 estimate the number of symbols for frequency domain equalization (the number of (D) described above). The MIMO channel H is up-sampled so as to match the preset MIMO detection range symbol number SS) in the conditions.

The Fourier transform units 45-1 and 45-2 convert time domain MIMO block number symbols corresponding to the number of symbols to be subjected to frequency domain equalization (preset MIMO detection range symbol number SS in the above condition (D)). Fast Fourier transform the sequence, data symbol sequence, etc. into the frequency domain.

The frequency domain MIMO channel equalization unit 46 performs MIMO channel H and frequency domain MIMO corresponding to the number of symbols for frequency domain equalization (preset MIMO detection range symbol number SS in condition (D) above). The block number symbol sequence, data symbol sequence, etc. (and noise power) are used to equalize the mixed transmitted signals x ₁ and x ₂ .

The inverse Fourier transform units 47-1 and 47-2 perform frequency-domain MIMO processing corresponding to the number of symbols subjected to frequency-domain equalization (preset MIMO detection range symbol number SS in the condition (D) described above). Signals such as block number symbol sequences and data symbol sequences are subjected to fast inverse Fourier transform in the time domain.

Here, since the pilot signal symbol number c is a power of 2, the received pilot signals can be fast Fourier transformed in the MIMO channel estimation units 44-1 and 44-2. Further, since the MIMO detection range symbol number SS is a power of 2, the MIMO detection range is fast Fourier transformed and fast inverse can be Fourier transformed.

Furthermore, even if the MIMO detection range shifts forward or a delayed wave exists, as shown in FIGS. Therefore, even if it is transformed into the frequency domain, it is not affected by these factors. In other words, the MIMO channel can be estimated with high accuracy, and MIMO channel equalization can be performed with high accuracy.

Therefore, when performing MIMO transmission using the SC-FDE scheme, the ratio of effective data increases with respect to the total transmission signal, so when compared at the same symbol rate, the transmission rate is made higher than that of the conventional technology. can improve transmission efficiency.

A pilot signal is composed of UWs and null data. In the examples shown in FIGS. 2 and 3, two consecutive UWs are arranged on a diagonal line, and other pilot signals are null data. Also, in the example shown in FIG. 4, null data are arranged on the diagonal line, and the pilot signals other than this are UW.

As a result, since the power of the pilot signal is not biased among the transmission signals, it is possible to estimate a MIMO channel with no bias in accuracy among the transmission signals on the receiving side, and obtain uniform reception performance among the transmission signals. be able to.

Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments, and can be variously modified without departing from the technical idea thereof.

For example, in the above embodiment, the number of transmissions is 2 or 4, but the number of transmissions may be a number other than 2 or 4. Further, in the above-described embodiment, the number of receptions is 2 or 4, but the number of receptions may be singular or plural other than 2 or 4.

The transmitting device 1 and receiving device 2 according to the embodiments of the present invention are useful for radio transmission systems such as broadcasting or communications that perform MIMO transmission using the SC-FDE scheme.

1 transmitter (single-carrier MIMO transmitter)
2 Receiving device (single-carrier MIMO receiving device)
10 transmission preprocessing unit 11 inter-system distribution unit 12 intra-interleaving unit 13 mapping unit 14 MIMO block number inserting unit 15 pilot signal inserting units 16, 63 band-limiting filter unit 17 digital quadrature modulation unit 18 DA conversion unit 19 transmission high-frequency unit 20 transmission Antenna 30 Reception antenna 40 Reception processing unit 41 MIMO block number detection unit 42 MIMO block number comparison unit 43 Noise power detection unit 44 MIMO channel estimation unit 45 Fourier transform unit 46 Frequency domain MIMO channel equalization unit 47 Inverse Fourier transform unit 48 Symbol determination /Likelihood calculation unit 49 Equalized MIMO block number decoding unit 50 Equalized MIMO block number determination unit 51 Internal deinterleaving unit 52 Decoding unit 60 High frequency reception unit 61 AD conversion unit 62 Digital orthogonal demodulation unit 64 Block synchronization unit a MIMO Number of block number symbols b Number of data symbols c Number of pilot signal symbols d Number of transmissions SS Number of MIMO detection range symbols α Detection target block

Claims (4)

A block of the MIMO SC-FDE scheme is generated for each of a plurality of transmission systems having a plurality of transmission antennas and corresponding to the plurality of transmission antennas, and a modulated wave of the block for each transmission system is transmitted through the transmission antenna. In a single-carrier MIMO transmission device that transmits by
an inter-system distribution unit that distributes an encoded bit sequence of data to be transmitted to the plurality of transmission systems;
a mapping unit for each transmission system that performs mapping using a predetermined modulation method on the encoded bit sequence of the data to be transmitted distributed by the inter-system allocation unit and outputs a bit sequence after mapping;
a MIMO block number inserting unit for each transmission system that inserts a MIMO block number at a predetermined position in the mapped bit sequence output by the mapping unit and outputs a symbol sequence in which the MIMO block number is inserted; ,
Two consecutive pilot signals are inserted at a predetermined position into the symbol sequence in which the MIMO block number is inserted, which is output by the MIMO block number inserting unit, and the two consecutive pilot signals, the MIMO block number and a pilot signal insertion unit for each transmission system that generates a symbol sequence of a detection target block composed of the same number of blocks as the number of transmission systems, in units of the block composed of the data to be transmitted;
Let the number of symbols of the MIMO block number be the number of MIMO block number symbols, let the number of symbols of the data to be transmitted be the number of data symbols, let the number of symbols of the pilot signal be the number of pilot signal symbols, c, and the plurality of transmitting antennas. is the number of MIMO transmissions d, and the number of symbols in the MIMO detection range where equalization is performed in the frequency domain is the number of symbols in the MIMO detection range SS,
The MIMO detection range is a range from the MIMO block number included in the first block in the detection target block to the first pilot signal included in the first block in the detection target block next to the detection target block. ,
The pilot signal insertion unit is
When a matrix is constructed with the two consecutive pilot signals contained in the detection target block in the plurality of transmission systems as one element, two consecutive UWs (unique words) consisting of known fixed pattern signals the elements are arranged on the diagonal of said matrix (A),
Of all the pilot signals constituting the matrix, the pilot signals other than the two consecutive UWs arranged on the diagonal line are null data (B);
The pilot signal symbol number c is a power of 2 (C),
The MIMO detection range symbol number SS is a power of 2, and is represented by the formula: SS = (a + b) × d + c × (2 × d−1) (D), and the first in the detection target block The two consecutive pilot signals are inserted at predetermined positions so as to satisfy each condition that the two consecutive pilot signals contained in the block are the same (E), and the symbol sequence of the block to be detected is A single-carrier MIMO transmission apparatus characterized by: A block of the MIMO SC-FDE scheme is generated for each of a plurality of transmission systems having a plurality of transmission antennas and corresponding to the plurality of transmission antennas, and a modulated wave of the block for each transmission system is transmitted through the transmission antenna. In a single-carrier MIMO transmission device that transmits by
an inter-system distribution unit that distributes an encoded bit sequence of data to be transmitted to the plurality of transmission systems;
a mapping unit for each transmission system that performs mapping using a predetermined modulation method on the encoded bit sequence of the data to be transmitted distributed by the inter-system allocation unit and outputs a bit sequence after mapping;
a MIMO block number inserting unit for each transmission system that inserts a MIMO block number at a predetermined position in the mapped bit sequence output by the mapping unit and outputs a symbol sequence in which the MIMO block number is inserted; ,
Two consecutive pilot signals are inserted at a predetermined position into the symbol sequence in which the MIMO block number is inserted, which is output by the MIMO block number inserting unit, and the two consecutive pilot signals, the MIMO block number and a pilot signal insertion unit for each transmission system that generates a symbol sequence of a detection target block composed of the same number of blocks as the number of transmission systems, in units of the block composed of the data to be transmitted;
Let the number of symbols of the MIMO block number be the number of MIMO block number symbols, let the number of symbols of the data to be transmitted be the number of data symbols, let the number of symbols of the pilot signal be the number of pilot signal symbols, c, and the plurality of transmitting antennas. is the number of MIMO transmissions d, and the number of symbols in the MIMO detection range where equalization is performed in the frequency domain is the number of symbols in the MIMO detection range SS,
The MIMO detection range is a range from the MIMO block number included in the first block in the detection target block to the first pilot signal included in the first block in the detection target block next to the detection target block. ,
The pilot signal insertion unit is
When a matrix is configured with the two consecutive pilot signals included in the detection target block in the plurality of transmission systems as one element, null data elements are arranged on a diagonal line of the matrix (A),
Of all the pilot signals constituting the matrix, the pilot signals other than the null data arranged on the diagonal are two consecutive UWs (unique words) consisting of known fixed pattern signals (B ),
The pilot signal symbol number c is a power of 2 (C),
The MIMO detection range symbol number SS is a power of 2, and is represented by the formula: SS = (a + b) × d + c × (2 × d−1) (D), and the first in the detection target block The two consecutive pilot signals are inserted at predetermined positions so as to satisfy each condition that the two consecutive pilot signals contained in the block are the same (E), and the symbol sequence of the block to be detected is A single-carrier MIMO transmission apparatus characterized by: A modulated wave transmitted from a plurality of transmission antennas provided in a single-carrier MIMO transmission device is received by a single or a plurality of corresponding reception systems via the single or a plurality of reception antennas. Then, a single-carrier MIMO receiver that estimates a MIMO channel based on a received pilot signal included in a received signal in which MIMO SC-FDE blocks are multiplexed and performs equalization in the frequency domain,
the block consists of two consecutive pilot signals, a MIMO block number and data;
Let the number of symbols of the MIMO block number be a number of MIMO block number symbols, let the number of symbols of the data be the number of data symbols b, let the number of symbols of the pilot signal be the number of pilot signal symbols c, and let the number of the plurality of transmitting antennas be Let d be the number of MIMO transmissions, let SS be the number of symbols in the MIMO detection range in which equalization is performed in the frequency domain, and
A detection target block is composed of the same number of blocks as the number d of MIMO transmissions, and the MIMO detection range is calculated from the MIMO block number included in the first block in the detection target block. The range up to the first pilot signal included in the first block in the next detection target block,
When a matrix is configured with the two consecutive pilot signals included in the detection target block in a plurality of transmission systems of the single-carrier MIMO transmission device as one element, two consecutive signals of known fixed patterns UW (unique word) elements are arranged on the diagonal of the matrix (A),
Of all the pilot signals constituting the matrix, the pilot signals other than the two consecutive UWs arranged on the diagonal line are null data (B);
The pilot signal symbol number c is a power of 2 (C),
The MIMO detection range symbol number SS is a power of 2, and is represented by the formula: SS = (a + b) × d + c × (2 × d−1) (D), and the first Assuming that the two consecutive pilot signals contained in a block are the same (E),
Fast Fourier transform the pilot signal, estimate the MIMO channel, perform upsampling of the MIMO channel so as to match the preset MIMO detection range symbol number SS, and output the MIMO channel after upsampling. a MIMO channel estimator for each receiving system,
a Fourier transform unit for each receiving system that fast Fourier transforms the MIMO detection range corresponding to the preset MIMO detection range symbol number SS and outputs a frequency domain signal;
The up-sampled MIMO channel output by the MIMO channel estimator for each reception system and the frequency domain signal output by the Fourier transform unit for each reception system are input, respectively, and the preset MIMO a frequency domain MIMO channel equalization unit that performs MIMO channel equalization in the frequency domain using the upsampled MIMO channel corresponding to the number of detection range symbols SS and the frequency domain signal,
The MIMO channel estimator,
extracting the received pilot signals included in the same number of blocks as the number d of MIMO transmissions constituting the detection target block from the signal received by the receiving system, fast Fourier transforming the received pilot signals, and performing the reception estimating a channel response between each of the plurality of transmit antennas and the receive antenna of the receive system by dividing a pilot signal fast Fourier transform result by the UW fast Fourier transform result in the time domain; A single-carrier MIMO receiver characterized by: A modulated wave transmitted from a plurality of transmission antennas provided in a single-carrier MIMO transmission device is received by a single or a plurality of corresponding reception systems via the single or a plurality of reception antennas. Then, a single-carrier MIMO receiver that estimates a MIMO channel based on a received pilot signal included in a received signal in which MIMO SC-FDE blocks are multiplexed and performs equalization in the frequency domain,
the block consists of two consecutive pilot signals, a MIMO block number and data;
Let the number of symbols of the MIMO block number be a number of MIMO block number symbols, let the number of symbols of the data be the number of data symbols b, let the number of symbols of the pilot signal be the number of pilot signal symbols c, and let the number of the plurality of transmitting antennas be Let d be the number of MIMO transmissions, let SS be the number of symbols in the MIMO detection range in which equalization is performed in the frequency domain, and
A detection target block is composed of the same number of blocks as the number d of MIMO transmissions, and the MIMO detection range is calculated from the MIMO block number included in the first block in the detection target block. The range up to the first pilot signal included in the first block in the next detection target block,
When a matrix is configured with the two consecutive pilot signals included in the detection target block in a plurality of transmission systems of the single-carrier MIMO transmission apparatus as one element, null data elements are arranged on the diagonal of the matrix. Teori (A),
Of all the pilot signals constituting the matrix, the pilot signals other than the null data arranged on the diagonal are two consecutive UWs (unique words) consisting of known fixed pattern signals (B ),
The pilot signal symbol number c is a power of 2 (C),
The MIMO detection range symbol number SS is a power of 2, and is represented by the formula: SS = (a + b) × d + c × (2 × d−1) (D), and the first in the detection target block Assuming that the two consecutive pilot signals contained in a block are the same (E),
Fast Fourier transform the pilot signal, estimate the MIMO channel, perform upsampling of the MIMO channel so as to match the preset MIMO detection range symbol number SS, and output the MIMO channel after upsampling. a MIMO channel estimator for each receiving system,
a Fourier transform unit for each receiving system that fast Fourier transforms the MIMO detection range corresponding to the preset MIMO detection range symbol number SS and outputs a frequency domain signal;
The up-sampled MIMO channel output by the MIMO channel estimation unit for each reception system and the frequency domain signal output by the Fourier transform unit for each reception system are input, respectively, and the preset MIMO a frequency domain MIMO channel equalization unit that performs MIMO channel equalization in the frequency domain using the upsampled MIMO channel corresponding to the number of detection range symbols SS and the frequency domain signal,
The MIMO channel estimator,
extracting the received pilot signals included in the same number of blocks as the number d of MIMO transmissions constituting the block to be detected from the signals received by the receiving system, and extracting the same number of the received pilot signals as the number d of MIMO transmissions constituting the detection target block; are respectively fast Fourier transformed, and based on the fast Fourier transform results of the received pilot signals and the time domain fast Fourier transform results of the UW, each of the plurality of transmitting antennas and the receiving antenna of the receiving system A single-carrier MIMO receiver characterized by estimating a channel response between.

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