WO2005055484A1 - Radio communication device, radio communication method, and radio communication system - Google Patents

Abstract

There is provided a radio communication method for performing communication between a first radio station having Ntx (>1) antenna groups and a second radio station. The method includes: a step for dividing user data to be transmitted into N systems; a step for creating a radio data packet composed of signal groupings of N systems obtained by adding N types of known pattern signals to the user data divided into the N systems; and a conversion step for repeatedly performing multiplication of the signal systems including the N-system known patterns by the respective coefficients while using combinations of different coefficients, synthesizing the N-system signal groupings whose coefficients have been multiplied in each of the combinations of the coefficients, and converting the N-system signal groupings into the Ntx-system signal groupings. Thus, by using the easy ZF method, it is possible to provide easy realization means of the transmission side technique for obtaining the maximum reception diversity gain at the reception station side.

Description

 Specification

 Wireless communication device, wireless communication method, and wireless communication system

 Technical field

 [0001] The present invention uses the same frequency channel, transmits independent data from a plurality of different transmitting antennas, receives signals using a plurality of receiving antennas, and uses a transfer function matrix between the respective transmitting and receiving antennas. In the high-speed wireless access system (or wireless LAN system) that realizes wireless communication by demodulating data at the receiving station side, the present invention relates to a receiving technique for achieving good transmission characteristics while suppressing a circuit scale. In addition, when using orthogonal frequency division multiplexing (OFDM) modulation in combination, transmission diversity gain can be gained at the base station side, and good characteristics can be obtained while suppressing the circuit scale on the wireless terminal side. Transmission technology. The present invention is used particularly for performing high-speed transmission of a high-speed wireless access system (or wireless LAN system) using the 2.4 GHz band and the 5 GHz band.

 Background art

 [0002] In recent years, as a high-speed wireless access system using the 2.4GHz band or the 5GHz band,

 The spread of wireless LAN systems based on the IEEE802.11g standard, IEEE802.11a standard, etc. is remarkable. In these systems, transmission speeds of up to 54 Mbps have been realized. With the spread of wireless LAN, further higher transmission speeds are required!

 For this purpose, MIMO (Multiple-Input Multiple-Output) technology is promising. This MIMO technology means that the transmitting station transmits different independent signals on the same channel from multiple transmitting antennas, and the receiving station receives signals using the same multiple antennas. A transfer function matrix is obtained, and an independent signal transmitted from each antenna card is estimated on the transmitting station side using the matrix to reproduce data.

[0003] Here, a case is considered where N signals are transmitted using N transmission antennas and signals are received using M antennas. First, there are NXM transmission paths between the antennas of the transmitting and receiving stations, and the signals are transmitted from the i-th transmitting antenna and received by the j-th receiving antenna. Let h be the transfer function of, and let H be the matrix of M rows and N columns that uses this as the (Li) -th component. In addition,

 Let the transmitted signal from the i-th transmitting antenna be t, and let Tx i 1 2 3 N be a column vector with components (t, t, t, t)

 , R is the received signal at the jth receive antenna, and Rx j 1 2 3 is a column vector with (r, r, r,.

 , And the column vector with (η, η, η,... N) as the component is n and Table j 1 2 3

 Write.

 In this case, the following relational expression holds.

[0004] [number 1]

Rx-HxTx + n… (1)

[0005] Therefore, there is a need for a technique for estimating a transmission signal Tx based on a signal Rx received on the receiving station side. The most basic as those of the MIMO technique, a method commonly referred to as ZF (Zero Forcing) method and the like (e.g., see Non-Patent Document 1.) ₀

Here, a process of obtaining the inverse matrix H- ¹ of the transfer function matrix with respect to the above (Equation 1) and multiplying this by the left side of both sides of the equation is performed. As a result, the following equation is obtained.

 [0006] [Number 2]

H ~ ^l xRx = Tx + H ~ ^] … (2)

[0007] That is, by combining the signals received by each receiving antenna, when the process of removing the interference due to signals other than the desired transmit antenna, actual transmission signal vector Tx in small Netsuzatsu sound claim H ^_1 Xn Will be obtained. Here, when a signal subjected to multi-level modulation such as BPSK, QPSK, 16QAM, or 64QAM is used as a transmission signal, signal points that can be taken as the transmission signal are discontinuous. Therefore, a hard decision process is performed to search the transmission constellation for the V ヽ point with the closest Euclidean distance to H−, and a true transmission signal is estimated.

In the above ZF method, the thermal noise term H−n is sufficiently small and If it can be assumed that the components are uniform, good characteristics can be expected. However, in general, this assumption does not hold, and the expected value of the absolute value of the thermal noise H ¹ Xn for each transmission antenna differs for a certain transfer function matrix. Furthermore, if the transfer function matrix H is a matrix whose inverse matrix is zero (or its determinant is very small), the estimation of the transmitted signal becomes very unstable. In such a situation, there is a possibility that the reception characteristics are significantly deteriorated. As a method for solving such a problem, for example, the MMSE (Minimum Mean Square Error) method is cited as an example.

[0009] In the case of the MMSE method, another matrix operator F is used in which the operator multiplied from both sides of (Equation 1) is not an inverse matrix of the transfer function matrix H. This matrix operator F is expressed as (FX Rx (k) when the transmission signal vector at the k-th symbol of the transmission signal is Tx (k) and the reception signal vector at the k-th symbol of the reception signal is Tx (k). ) —Tx (k)) Select the matrix operator F such that it is expected to minimize the expected value over multiple symbols of ^H X (FX Rx (k) —Tx (k)). In practice, the matrix operator F is estimated using a known preamble signal part, and the estimated matrix operator F is used in demodulation of subsequent data.

 [0010] As described above, it is possible to increase the transmission capacity by performing communication by applying the MIMO technology, but separate signals transmitted from a plurality of transmission antennas may interfere with each other. Therefore, the use of a plurality of antennas on the receiving side is expected to achieve reception diversity gain, but it is not possible to maximize the diversity gain in the process of canceling this interference mutually. ,.

That is, in the ZF method, the inverse matrix of the transfer function matrix H is used in order to remove the interference between the sequences of each signal sequence and separate the signals, but this is only the mutual interference between the signal sequences. The objective is to eliminate the noise, but not to maximize the diversity gain due to combining between the receiving antennas. Normally, it is preferable to perform the signal separation process with a policy of maximizing the S / N ratio (signal-to-noise level ratio) of each signal sequence after signal separation. In order to maximize this S / N ratio, that is, to realize the maximum ratio combining process on the receiving side, it is necessary to adjust the signals at the receiving end so that the signal sequences are orthogonal at the receiving end and transmit the signals. There is. This method is called an E-SDM (Eigenbeam-Space Division Multiplexing) method (for example, see Non-Patent Document 2). [0011] This E-SDM scheme assumes that the transfer function matrix H is known on the transmitting side. Based on the matrix H, the product of the Hermitian conjugate matrix H of this matrix ^H and H, that is, the NXN matrix H ^H Transmits the signal UX Tx (k) that has been subjected to digital transformation. Here, the signal transmitted from the i-th transmitting antenna is [UXTx] (where [X] represents the 减 th component of vector X). If a signal that has been subjected to a series transformation including the preamble signal is transmitted, the transfer function matrix obtained by channel estimation will be HXU even if the actual transfer function matrix is H at the receiving station.

 [0012] Here, the following relational expression holds between the U-transformation matrix U and the matrix H.

[0013] [number 3]

… (3)

The matrix Λ on the right side of this (Equation 3) is a diagonal matrix of Ν X 、, and the diagonal components of the matrix are non-zero (each component is called an eigenvalue, and λ 1, λ 2, λ 3. The other diagonal components are zero. When this method is used, (Equation 1) is also converted as follows.

[0014] [number 4]

By applying the Hermitian conjugate matrix of the estimated transfer function matrix Η X U, the equation is transformed as follows.

[0015] [number 5]

(HU) ^H xRx = AxTx + (HxU) ⁿ x "… C5) This means that the N signal sequences are completely orthogonal. The matrix appearing on the right side can be obtained directly from (Equation 3) from the estimated transfer function matrix. Therefore, regardless of whether the original matrix H has the power to have the inverse matrix, the transmission signal Tx can be stably estimated for signal sequences with nonzero eigenvalues using (Equation 3) and (Equation 5). It is possible to do.

 [0016] It is understood that this Ε—SDM method is equivalent to the phased array antenna technology in which a signal is converted on the transmitting side so that the transmitted signal has directivity. it can. As a result, it is possible to obtain the diversity gain together while avoiding interference between the transmission antennas, so that very good characteristics can be expected.

 Here, FIG. 17 shows a configuration of a transmitting section of a first wireless station in the related art. In the figure, 100 is a data division circuit, 101-1 to 101-3 is a preamble addition circuit, 102-1 to 102-3 is a modulation circuit, 103 is a transmission signal conversion circuit, and 104-1 to 104-3 is a wireless circuit. , 105-1-1 105-3 is a transmitting antenna, 106 is a matrix operation circuit # 1, and 107 is a transfer function matrix management circuit. As an example, a case where a transmitting station transmits data of three systems using three transmitting antennas will be described.

First, the transfer function matrix Η managed by the transfer function matrix management circuit 107 is input to the matrix operation circuit 106. In the matrix operation circuit # 1 (106), for the input matrix Η, an ^Hermitian conjugate matrix Η ^、, their product Η ^Η Χ ュ, and a u Is input to the transmission signal conversion circuit 103. Next, when data is input, the data division circuit 100 separates the data into three systems. For example, the data of the first system is input to the brimble adding circuit 101-1 and is input to the modulation circuit (Ch 1) 102-1 with the preamble added.

The modulation circuit (Chi) 102-1 performs predetermined modulation, and the modulated signal is input to the transmission signal conversion circuit 103. In the transmission signal conversion circuit 103, the transmission signal Tx including the preamble signal is subjected to a digital transformation and input to the radio section 104-1 as the UX Tx. After that, it is converted to a radio frequency by radio section 104-1 and transmitted from transmitting antenna 105-1. Similarly, the data of the second system is transmitted individually via 101-2-105-2, and the data of the third system is transmitted individually via 101-3-105-3. FIG. 18 shows a configuration of a receiving unit of a second wireless station in the related art. In FIG. 18, 111—111—111—3 is a receiving antenna, 112—1—112—3 is a radio unit, 113 is a channel estimation circuit, 114 is a received signal management circuit, 115 is a transfer function matrix management circuit, and 116 is Matrix arithmetic circuits # 2 and 117 are matrix arithmetic circuits # 3 and 118, a hard decision circuit, and 119 is a data synthesis circuit.

 [0021] The first to third receiving antennas 111-1 to 111-3 individually receive received signals. The received signal is input to the channel estimation circuit 113 via the radio section 112-1 112-3. From the reception state of the predetermined preamble signal given on the transmitting side, the transfer function between each transmitting antenna and the receiving antenna is obtained here by the channel estimation circuit 113. The acquired information h of each transfer function is managed as a transfer function matrix H by the transfer function matrix management circuit 115.

 Here, the transfer function H is obtained by multiplying the transfer function of the actual transmission path by the unitary transformation matrix.

The matrix operation circuit # 2 (116) calculates H ^H and Η ^Η Λ 管理 (= Λ) based on the transfer function matrix H managed by the transfer function matrix management circuit 115. Here, as for each diagonal component of the matrix Λ, it is assumed that the (1, 1) component is λ, the (2, 2) component is λ, and the (3, 3) component is λ.

 one two Three

Note that the eigenvalues example by H ^H XH - in addition to determining the lambda, as an approximation, use the transfer function

 13

And you can ask for a feed from eh e ² .

This result is input to the matrix operation circuit # 3 (117). On the other hand, the data signal following the preamble signal is input to the reception signal management circuit 114 one symbol at a time. In the received signal management circuit 114, the received signal (r, r, r) ^T (T is the row vector power sequence

 one two Three

(Indicating the conversion into a vector) is managed as a received signal vector Rx having a component as a component. The received signal vector is multiplied by a matrix H ^{H in} a matrix operation circuit # 3 (117). Divide the vector obtained in this way by λ 1 for the first component, λ 2 for the second component, and λ 3 for the third component. To perform the first-order estimation of the transmitted signal vector. The result is input to the hard decision circuit 118, and the result is input to the data synthesis circuit 119. The data demodulated over all symbols reproduces the original data obtained by appropriately combining the signals for each system and outputs the data. FIG. 19 shows a transmission flow of the first wireless station in the related art. When data is input (step S100), the transmitting station divides the data into N data sequences (step S101), and adds a preamble signal to each of these signals (step S102). The modulation process is performed individually (step S103). The modulated signal is subjected to a unitary conversion (step S104), the signal after the unitary conversion is converted to a radio frequency by the radio unit, and the signal is transmitted (step S105).

FIG. 20 shows a reception flow of the second wireless station in the related art. Upon receiving the wireless packet (step S110), the receiving station detects a preamble (step S111) and performs channel estimation (step S112). Here, all the transfer functions between each transmitting antenna and receiving antenna are acquired. A Hermitian conjugate matrix H ^H and a matrix Η ^Η Χ = (= Λ), which is a product of the matrix and the Hermitian conjugate matrix H ^H , are calculated (step S 113).

On the other hand, a signal received subsequent to the preamble signal is managed as a received signal vector Rx having, as a component, a received signal r at each receiving antenna for each symbol (step S114). On the other hand, the matrix operation H ^H X Rx is performed, and each component of the obtained vector is divided by the diagonal components λ 1-λ 3 of the matrix ((step S115). Based on the result, a hard decision process is performed (step S116), and the estimation of the signal transmitted from each transmitting antenna of the corresponding symbol is determined (step S117). If the received data continues, the process returns to the processing step S114, and the processing steps S114 to S117 are repeated. When the reception data is completed (step S118), the reception data of each series is reconstructed, and the data on the transmission side is reproduced to output the data (step S119).

 Tokubi 1: S. Kurosaki, Y. Asai, T. Sugiyama and M. Umehira, A

 SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel

 Interference Canceller for MIMO Based Broadband Wireless LANs ", IEICE TRANS. COMMUN., V0I.E86 B. No.l, January, 2003

 Non-Patent Document 2: Shimo et al., “Eigen-Spatial Division Multiplexing (E—SDM) in MIMO Channel”, IEICE, RCS2002-53, May 2002

Disclosure of the invention Problems the invention is trying to solve

[0026] The biggest problem of this E-SDM method is that the transmitting station performs channel estimation accurately and U ^H

XH ^H XHXU must be operated in a situation where the off-diagonal components are clearly zero.

 For example, consider a case where wireless packets are continuously transmitted. The transmitting station first performs channel estimation by some method, obtains the transfer function matrix H, and obtains the utliary matrix U based on this. Naturally, wireless packets transmitted continuously are subjected to the same dictionary conversion.

However, since the transfer function matrix H fluctuates with time, the off-diagonal components of U ^H XH ′ ^H XH ′ XU do not become cleanly zero for the transfer function matrix H ′ after the change. Since the non-diagonal component causes inter-channel interference, the characteristics are rapidly deteriorated by the influence of the interference signal. Therefore, good characteristics cannot be expected unless the calculated U-transform U is very accurate.

 [0028] Also, in this Ε-SDM scheme, the signals of each signal sequence are each assigned a unique eigenvalue (row

1H ^HH XH is assumed to be a square matrix with Ν rows and Ν columns), so that individual modulation schemes can be adopted or transmitted by a method called the water injection theorem on the transmitting side. It is common to adjust the power distribution. In other words, it is premised that signal sequences are handled individually and independently to efficiently extract the characteristics of each sequence. However, such control is complicated and negotiates between transmitting and receiving stations. As a simple method for avoiding these, it is conceivable to transmit all the signal of the signal sequence with the same output and using a single modulation mode. However, in this case, the characteristic of a signal sequence having a large variation in the value of each eigenvalue, especially the minimum eigenvalue, is greatly deteriorated.

[0029] The above is the power when E-SDM is assumed. Here, let us consider the general characteristics of the MIMO technology combined with the OFDM modulation method. When OFDM modulation is used, the quality of each signal sequence varies for each of a plurality of subcarriers. Figures 21 and 22 show the frequency dependence of the characteristics of each signal sequence when both OFDM modulation and MIMO technology are used. In each figure, the horizontal axis represents the frequency, which effectively means the subcarrier number. The vertical axis represents BER (Bit Error Rate) as equivalent to transmission quality [0030] For example, when E-SDM is used or when the correlation between frequencies is strong, there is a large difference in the characteristics of each signal sequence as shown in FIG. For example, a signal sequence with a high BER in the entire frequency domain # 1 has a partial packet error rate (PER) with a code error of 20% and a signal sequence with a low BER in the entire frequency domain Suppose that the partial PER with a code error in # 2 is 0.0001%. If the number of superimposed MIMOs is 2, the average PER of the entire system is the sum of the PER of each signal sequence and divided by 2, which is almost 10%. In other words, if there is a bad signal sequence, the PER as a whole system will be pulled by this.

 On the other hand, as shown in FIG. 22, consider the case where the characteristics of signal sequence # 1 and signal sequence # 2 are reversed at a certain frequency, and each is significantly deteriorated in a specific frequency region. As described above, in the frequency domain where the characteristics are degraded, the error before the error correction is bursty, so that there is a high probability that the error cannot be corrected even if the error correction processing is performed. In other words, if the quality deteriorates continuously over a certain section on the frequency axis, the effect of error correction is weakened and the partial PER It appears as deterioration of characteristics.

 As described above, when the OFDM modulation and the MIMO technology are used together, particularly when the E-SDM method is used, in order to improve the PER characteristics of the entire system, code errors of a specific signal sequence are burst-like. However, it is preferable that they are randomized.

[0032] The present invention has been made in view of such circumstances, and when performing wireless communication using MIMO technology, while achieving the good characteristics of the E-SDM method, the accuracy is low. It is an object of the present invention to simply provide a wireless communication device, a wireless communication method, and a wireless communication system that can realize stable characteristics even when a digital transformation matrix is used.

Also, when performing wireless communication using both OFDM modulation and MIMO technology, a wireless communication method and a wireless communication device capable of randomizing code errors of each signal sequence and efficiently improving the PER characteristic of the entire system are provided. It is to provide easily. In addition, this device for randomization should be used for discriminating products as long as it can be dealt with only by changing the transmitting terminal side instead of changing the air interface specification for communication. Still preferred Yes.

 Means for solving the problem

 [0033] In order to solve the above problem, the present invention is a wireless communication device used in a wireless communication system configured by a first wireless station and a second wireless station,

 The first radio station has N or more first antenna groups (N is an integer greater than 1).

 tx tx

 e,

 Division means for dividing user data to be transmitted into N systems (N ≥ N> 1, where N is an integer);

 tx

 Means for constructing a wireless data packet composed of N series of signal sequences obtained by adding N types of known pattern signals to the user data divided into the N series,

The process of multiplying each of the N series of signal sequences including the known pattern by an individual coefficient is performed a plurality of times with different combinations of coefficients, and the N series of signal sequences multiplied by the coefficient for each combination of coefficients are synthesized. The signal sequence power of the N systems

 tx

 Conversion means for converting to a sequence of numbers;

 Transmitting means for transmitting the signal converted by the conversion means from the first antenna group;

 A wireless communication device is provided.

 [0034] In a preferred embodiment,

 The second wireless station includes M (M is greater than 1 and an integer) second antenna groups, and an i-th antenna in the first antenna group and a second antenna group in the second antenna group. j means for obtaining a transfer function h between the antenna and an approximate value thereof,

 J, i

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 J, i

Means for calculating a conjugate matrix H ^H ,

Means for calculating a matrix product of the two matrices, that is, a matrix H ^H XH of N rows and N columns; anda means for calculating a unitary matrix U for diagonalizing the matrix H ^H XH, The conversion means is

 Information of the k-th symbol (k is an integer of 1 or more) of the N signal sequences is (x

 One

(k), x (10, ···, x (k)}, the column vector x (k) with each piece of information of the k-th symbol as

 2 N

Means for calculating a column vector given by the product of the matrix U, i.e., UX x (k), The transmitting means,

 The i-th row component of the column vector U X x (k) [U X

 Including means for transmitting from

 In this case, in applying the MIMO technology, it is possible to provide a simple means for realizing the transmission-side technology for maximizing the reception diversity gain at the receiving station side while utilizing a simple ZF method or the like.

As a preferred example,

 Means for transmitting a first wireless control packet containing control information prior to transmitting the wireless data packet;

 Means for receiving, using N or more antennas, a second radio control packet that is a response to the first radio control packet,

 The acquisition means uses a plurality of signals of known patterns provided to the second wireless control packet, and obtains the j-th (l ≤j≤M, including means for calculating the transfer function h between the antenna and the i-th (l≤N, i is an integer) antenna used for reception by the first radio station

 J, i

 Sorry.

 The function of the first wireless station is to provide the transmitting side with a simple realization method for obtaining a transfer function matrix.

 [0036] As another preferred example, prior to transmission of the wireless data packet, a signal sequence including N known patterns is used as the first wireless control packet by using the N first antenna groups. Means for transmitting;

 Means for receiving a second wireless control packet that is a response to the first wireless control packet;

 Information about a transfer function h between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group accommodated in the second radio control packet.

 J, i

 Means for obtaining;

 Can be included.

[0037] In the communication between the radio stations, K subcarriers (K is an integer greater than 1) are used. Orthogonal frequency division multiplexing (OFDM) modulation may be used.

As a preferred example in this case, a radio control packet and / or user data containing control information in which a plurality of signal sequences are not superimposed, that is, only one signal sequence, is received from the second radio station. When the received radio data packet is received, the reception status of the signal of the known pattern received by each reception antenna is transmitted by the second radio station of the ks (l≤ks≤K, where is an integer) subcarrier Transfer function between antenna j (l≤j≤M, where j is an integer) used for antenna and antenna i (l≤N, i is an integer) used for reception by the first radio station h ^[ks]

 , And transfer function obtaining means for obtaining.

As still another preferred example, in the strong ks '(l≤ks'≤K, ks' is an integer) subcarrier transmitted by the jth antenna of the second radio station, The transfer function h ^[ks ′ ^] between the j-th antenna and the i-th antenna of the first wireless station is determined by the j-th antenna of the second wireless station.

 ,

Ks ≠ ks and ks ≠ ks transmitted by the antenna, (l≤ks≤K, l≤ks≤K, ks, ks is an integer) and the transfer function h ^[ksl for the ks subcarrier and the ks subcarrier ^{] And} h ^[ks2] include transfer function obtaining means for obtaining h ^[ks ′ ^] by interpolation or extrapolation.

 ,

 This provides a simple realization method for obtaining a transfer function matrix on the transmission side. If this method is used, even if the existing wireless LAN system is extended by applying MIMO technology, the existing frame format can be changed or special control messages can be newly added. It is also possible to obtain the effect of realizing while maintaining knock word compatibility that is unnecessary, and in these preferred embodiments, the transfer function acquisition means is provided on the first wireless station side. May be provided to the second wireless station.

 The present invention is also a wireless communication device for receiving a wireless signal from the wireless communication device at the second wireless station,

 The second wireless station includes M (M is an integer of 1 or more) second antenna group, means for individually receiving a wireless signal using the second antenna group,

Each signal received using the signal of a known pattern given to the received signal as a reference signal Demodulation means for separating and demodulating a sequence signal;

 Output means for synthesizing all demodulated signal sequences and outputting them as user data.

 The present invention also provides a wireless communication system including the above-described transmitting-side wireless communication device and the above-described receiving-side wireless communication device.

 As a typical example, the demodulation means includes:

 A transfer function h between an i-th antenna in the first antenna group and a j-th antenna in the second antenna group is defined as a signal of a known pattern given to the received signal as a reference signal. Means for obtaining;

 ,

 A predetermined operation is performed on an M-by-N matrix H having the transfer function h as the (j, i) -th component, and 、

 ,

 Calculating means for obtaining a vector corresponding to the signal point of the transmission signal of the system,

 The output means,

 Means for combining N transmission signals provided by the respective elements of the vector obtained by the calculation with all the received symbols and outputting the resultant as the user data.

[0040] The calculating means includes:

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 ,

Means for calculating a conjugate matrix H ^H ,

Means for calculating a matrix product of the two matrices, that is, an N-by-N matrix H ^H XH; and means for calculating an inverse matrix of the matrix H ^H XH, that is, (H ^H XH) ¹

Means for calculating a matrix (H ^H XH) ¹ XH ^H using these,

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) Calculate (H ^H XH) ¹ XH ^H X Rx (k) for the received signal level Rx (k) represented by ^T (T indicates conversion to row vector power column vector) Means,

 May be included.

[0041] Further, the calculating means includes:

For an N-by-N matrix H having the transfer function h as the (j, i) -th component, an inverse matrix Η— ^{1 of the} matrix Η

 ,

Means for calculating Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

On the received signal Besotoru Rx (k) represented by the illustrated), means for calculating the H- ¹ X Rx (k), may be included.

 The function of the second radio station is to provide a simple means for implementing the ZF method on the receiving station side by utilizing the fact that the matrix is a square matrix.

[0042] Further, the calculating means includes:

The transmission signal of the k-th symbol transmitted from the n-th antenna of the first antenna group is denoted by t (k), and the reception of the k-th symbol actually received by the m-th antenna of the second antenna group If a signal is expressed as r (k), then (t (k), t (10,..., ^T (k)) ^T

Tx (k), (r (k), r (k),---, r (k)) ^T

 1 2

For a received signal vector Rx (k) expressed by: and a matrix operator F, a vector FX Rx (k) —Tx (k) and a vector of Hermitian conjugate of the vector (FX Rx (k) −Tx (k) ) ^H vector product of (FX Rx (k) -Tx ( k)) H X to the expected value across multiple symbols (FX Rx (k) -Tx ( k)) and the minimization child is expected Means for selecting the matrix operator F;

 Means for calculating F X Rx (k) for each symbol;

 May be included.

 The function of the second wireless station is to provide the receiving station with a means for using the MMSE method instead of the ZF method.

 The matrix operator F may be obtained by an MMSE (Minimum Mean Square Error) method.

As a preferred example of the wireless communication device,

 On the second wireless station side,

 Upon receiving a first wireless control packet from the first wireless station,

 Means for transmitting, as a response to the first wireless control packet, a second wireless control packet containing a plurality of known patterns.

[0044] As another preferable example,

On the second wireless station side, Upon receiving a first radio control packet containing N known patterns from the first radio station,

 Means for calculating the transfer function h using the signals of the N known patterns;

 J, i means for transmitting a second radio control packet containing information on the transfer function as a response to the first radio control packet;

 Having.

 In the communication between the radio stations, an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is an integer greater than 1) may be used. .

 In this case, on the second wireless station side,

 When transmitting the radio control packet or the radio data packet to the first radio station without superimposing a plurality of signal sequences, a signal of the ks subcarrier is converted to a second signal corresponding to a subcarrier number ks. Transmission means for transmitting using a predetermined one of the antenna groups may be provided.

 Here, a means may be provided for notifying the first wireless station that the second wireless station has the transmitting means.

[0046] The present invention also provides a wireless communication method for performing communication between a first wireless station and a second wireless station,

 The first radio station has N or more first antenna groups (N is an integer greater than 1).

 tx tx

 e,

 A dividing step of dividing user data to be transmitted into N systems;

 Constructing a wireless data packet composed of N signal sequences obtained by adding N types of known pattern signals to the user data divided into N signals;

 The process of multiplying each of the N series of signal sequences including the known pattern by an individual coefficient is performed a plurality of times with different combinations of coefficients, and the N series of signal sequences multiplied by the coefficient for each combination of coefficients are synthesized. The signal sequence power of the N systems

tx A conversion step for converting to a series of numbers;

 Transmitting the signal converted in the converting step, the first antenna group power transmitting step;

 And a wireless communication method comprising:

[0047] Typically, the second wireless station includes M (M is an integer greater than 1) second antenna groups,

 Obtaining a transfer function h or an approximate value thereof between an i-th antenna in the first antenna group and a j-th antenna in the second antenna group;

 ,

 For an M-by-N matrix H having the transfer function h as the (j, i) -th component, the Hermitian,

Calculating a conjugate matrix H ^H ;

Calculating a matrix product of the two matrices, i.e., a matrix H ^H XH of N rows and N columns; anda calculating a dictionary matrix U for diagonalizing the matrix H ^H XH, further comprising: The conversion step is

 Information of the k-th symbol (k is an integer of 1 or more) of the N signal sequences is (x

(k), x (10,..., x (k)}, a column vector given by the product of the matrix U and a column vector x (k) having elements of each information of the k-th symbol, Including the step of calculating UX x (k)

The transmitting step includes:

 And transmitting the i-th row component [U X x (k)] of the column vector U X x (k) from the i-th antenna in the first antenna group.

[0048] As a preferred example, before transmitting the wireless data packet, transmitting a first wireless control packet containing control information;

 Receiving, using N or more antennas, a second radio control packet that is a response to the first radio control packet,

The obtaining step uses the signals of a plurality of known patterns given to the second wireless control packet, and determines the j-th (l≤ j≤M, where j is an integer) and calculating a transfer function h between the ith (l≤i≤N, i is an integer) antenna used for reception by the first wireless station. [0049] As another preferred example, prior to transmission of the wireless data packet, a signal sequence including N known patterns is used as a first wireless control packet by using the N first antenna groups. Sending,

 Receiving a second wireless control packet that is a response to the first wireless control packet;

 Information on a transfer function h between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group contained in the second radio control packet is represented by:

 Obtaining,

 including.

 In the communication between the radio stations, an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is larger than 1 and an integer) may be used. .

As a preferred example in this case, a radio control packet and / or user data containing control information in which a plurality of signal sequences are not superimposed, that is, only one signal sequence, is received from the second radio station. When the received radio data packet is received, the reception status of the signal of the known pattern received by each reception antenna is transmitted by the second radio station of the ks (l≤ks≤K, where is an integer) subcarrier The transfer function h ^[ks] between the j-th antenna (l≤j≤M, where j is an integer) used for antenna and the i-th (l≤N, i is an integer) antenna used for reception by the first radio station, And a transfer function obtaining step of obtaining

As still another preferred example, in the strong ks '(l≤ks'≤K, ks' is an integer) subcarrier transmitted by the jth antenna of the second radio station, The transfer function h ^[ks ′ ^] between the j-th antenna and the i-th antenna of the first wireless station is represented by j-th and

Ks ≠ ks and ks ≠ ks transmitted by the antenna, (l≤ks≤K, l≤ks≤K, ks, ks is an integer) and the transfer function h ^[ksl for the ks subcarrier and the ks subcarrier ^And a transfer function obtaining step of obtaining h ^[ks ′ ^] by interpolation or extrapolation of h ^[ks2] .

 ,

 According to these preferred examples, the method may include a step of notifying the second wireless station that the transfer function acquiring step is to be performed on the first wireless station.

[0051] The present invention also provides a radio signal transmitted by the radio communication method to the second radio station. 無線 a wireless communication method for receiving

 The second radio station includes M (M is an integer of 1 or more) second antenna groups, and individually receives a radio signal using the second antenna group; and A demodulation step of separating and demodulating a signal of each received signal sequence using the signal of the known pattern as a reference signal,

 An output step of synthesizing all demodulated signal sequences and outputting them as user data.

[0052] Typically, the demodulation step includes:

 A transfer function h between an i-th antenna in the first antenna group and a j-th antenna in the second antenna group is defined as a signal of a known pattern given to the received signal as a reference signal. Obtaining,

 ,

 A predetermined operation is performed on an M-by-N matrix H having the transfer function h as the (j, i) -th component, and 、

 ,

 Calculating a vector corresponding to the signal point of the transmission signal of the system, and the output step,

 The method includes a step of combining N transmission signals provided by each element of the vector obtained by the operation with all the received symbols and outputting the resultant as the user data.

[0053] As a preferred example, the calculation step includes:

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 ,

Calculating a conjugate matrix H ^H ;

Calculating a matrix product of the two matrices, that is, a matrix H ^H XH of N rows and N columns; and calculating an inverse matrix of the matrix H ^H XH, that is, (H ^H XH) ¹ ;

Further calculating a matrix (H ^H XH) ¹ XH ^H using these;

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) Calculate (H ^H XH) ¹ XH ^H X Rx (k) for the received signal level Rx (k) represented by ^T (T indicates conversion to row vector power column vector) Steps and

 including.

[0054] As another preferred example, the calculation step includes: For an N-by-N matrix H having the transfer function h as the (j, i) -th component, an inverse matrix H— ^{1 of the} matrix H

 J, i

 Calculating

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

On the received signal vector Rx (k) represented by the illustrated), comprising a step of computing H ¹ X Rx (k), the.

 [0055] As still another preferred example, in the calculation step, the transmission signal of the k-th symbol transmitted from the n-th antenna of the first antenna group is set to t (k), and the second antenna group When the received signal of the k-th symbol actually received by the m-th antenna of notation is denoted by r (k), (t

 m

(k), t (k),---, t (k)) Transmission represented by ^T (T indicates conversion to row vector power column vector)

1 2 N

Signal vector Tx (k), (r (k), r (k),---, r (k)) received signal vector Rx (k) represented by ^T , and

 1 2 M

For the matrix operator F, the vector! ⁷ X Rx (k) —the vector product of Tx (k) and the vector of Hermitian conjugates (FX Rx (k) -Tx (k)) ^H of the vector (FX Rx (k ) -Tx (k)) ^H X (FX Rx (k) —select matrix operator F such that it is expected to minimize the expected value over multiple symbols of Tx (k)) ,

 Calculating F X Rx (k) for each symbol;

 including.

 In this case, the matrix operator F may be obtained by an MMSE (Minimum Mean Square Error) method.

 [0056] As another preferred example, the second wireless station side includes:

 Upon receiving a first radio control packet containing N known patterns from the first radio station,

 Step of calculating the transfer function h using the signals of the N known patterns.

 J, i

 And

 Transmitting a second wireless control packet containing information on the transfer function as a response to the first wireless control packet;

 Run

[0057] As another typical example, on the second wireless station side, Upon receiving a first wireless control packet from the first wireless station, transmitting a second wireless control packet containing a plurality of known patterns as a response to the first wireless control packet. Execute.

 As another typical example, for the orthogonal frequency division multiplexing (OFDM) modulation scheme using K subcarriers (K is greater than 1 and an integer) in communication between the radio stations. Puru.

 In this case, on the second wireless station side,

 When transmitting the radio control packet or the radio data packet to the first radio station without superimposing a plurality of signal sequences, a signal of the ks subcarrier is converted to a second signal corresponding to a subcarrier number ks. A transmission step of transmitting using a predetermined one of the antenna groups may be performed!

 Here, a step of notifying the first wireless station that the second wireless station performs the transmitting step may be included.

[0059] As another typical embodiment of the wireless communication device of the present invention,

 A wireless communication device used in a wireless communication system that performs wireless communication using an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of subcarriers.

 The dividing means divides user data to be transmitted into N systems individually for each subcarrier,

 The conversion means, the information of the n-th (n is an integer of 1 or more) symbol of the N series of signal sequences in a certain subcarrier is (x (n), x (n), ..., χ (n) } And these

 1 s 2 s N s

 Is an N-row column vector force x (n) having as its components an N-by-N identity matrix or s

 Are N (N> 1: N is an integer) types of rotated rows obtained by appropriately replacing the columns of the unit matrix.

 R R R

 When a group of columns is expressed as {R} (N ≥ k ≥ l: k is an integer), a predetermined k R corresponding to each subcarrier

 k means using R for k, at least means for converting the vector x (n) to RX x (n), and ksks means for transmitting the first component of the converted column vector in each subcarrier as described in the first one. The antenna is transmitted from the i-th antenna of the antenna group.

[0060] As a preferred example, the conversion unit includes a first antenna group for each subcarrier. Convert the signal of the n-th symbol transmitted from the i-th antenna into [RX x (n)] sks 1

To do.

With this configuration, when using MIMO technology, the antennas used to transmit each signal sequence for each subcarrier are switched, and as a result, errors for each signal sequence are averaged and randomized, and coding for error correction is performed. Improve gain. With the conventional method, for a predetermined k corresponding to each subcarrier, an _nth symbol signal transmitted from the ith antenna of the first antenna group in the subcarrier is converted using a rotation matrix R. [

 s k

 R Χ χ (η)], and the converted signal [R Χ χ k s i k in each subcarrier

(n)] from the i-th antenna of the first antenna group.

 s 1

 As a result, when performing highly efficient wireless communication using MIMO technology, it becomes possible to equalize the reception characteristics of each of a plurality of signal sequences to be superimposed, and to randomize code errors on a transmission path. In particular, when combined with the E-SDM scheme, there is a tendency for MIMO technology to have a large variation in reception characteristics between signal sequences to be superimposed. By averaging the characteristics and randomizing the errors, as a result, the effect of improving the error correction gain and improving the packet error rate characteristics as a whole can be obtained.

 In another preferred embodiment, the second radio station includes M (M is an integer of 1 or more) second antenna groups,

 Individually for each subcarrier,

 Means for obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group,

 ,

 For an M-by-N matrix H with the transfer function h as the (j, i) -th component, the

 ,

Means for calculating a matrix H ^H

Means for calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH, and means for calculating an N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, Further comprising

 The conversion means converts the signal of the n-th symbol transmitted from the i-th antenna of the first antenna group in each subcarrier to [U X R X x (n)].

sks 1 As a result, when the E-SDM scheme is used in combination with the MIMO technique, a large difference occurs in the characteristics of the signal sequence to be superimposed. However, this characteristic is made uniform, and as a result, errors for each signal sequence are averaged. It is possible to provide a simple realizing method for improving coding gain in error correction by randomization and randomization.

 In another preferred embodiment, the second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 N> N,

 Individually for each subcarrier,

 Means for obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group,

 ,

Means for calculating an Ermite conjugate matrix H ^H of the M-by-N matrix H having the transfer function h as the (j, i) -th component,

Means for calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH, and means for calculating an N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, Further comprising

 The conversion means is a matrix having N rows and N columns, and for an integer j such that N≥j≥l, a matrix in which only the (j, j) -th component is 1 and other components are 0 is expressed as Then, the signal of the n-th symbol transmitted from the i-th antenna (N≥i≥l: i is an integer) of the first antenna group in each subcarrier is converted into [UXTXRX x (n)]. To do.

With this configuration, a signal of the n-th symbol transmitted from the i-th antenna (N ≥ i ≥ l: i is an integer) of the first antenna group for a predetermined k corresponding to each subcarrier is transmitted. By a matrix U for diagonalizing H ^H XH of the function matrix H, a rotation matrix R for exchanging antennas, and a matrix T for expanding the number of antennas, [UXTXR Xx (n)] is obtained. Converted

, And transmits the converted signal [UXTXR Xx (n)] from the first antenna of the first antenna group.

As a result, the number of transmitting antennas is increased from the number of signal sequences to be superimposed, and the MIMO channels that have the number of transmitting antennas have poor neutral characteristics! The channels are truncated, and the above processing is performed using only channels with good characteristics. Provides a simple implementation method for implementing it can.

 As a typical example, the rotation matrix group {R} is obtained by appropriately replacing columns of a unit matrix of N rows and N columns.

 k

One of the selected matrices is R, and for the integer j such that N> j≥l, only the (j + 1 J) and (1, Ν) components are 1 and the other components are 1. Let ^ be the matrix of Ν rows and Ν columns that is the force ^, and furthermore, for an integer k such that N≥k≥2, a total of N pieces given as R = P ^k_1 XR

 k 1

 Composed of a matrix,

 The rotation matrix R used for a subcarrier in which user information is

 k

 Each matrix of the transposed matrix group {R} is rearranged appropriately, and paired in order with N subcarrier periods.

 k

 Respond.

 This can provide a simple realization method for generating a matrix used as the above-described rotation matrix.

 [0064] As another typical example, the rotation matrix group {R} includes columns of a unit matrix of N rows and N columns as appropriate.

 k

One of the selected matrices is R, and for the integer j such that N> j≥l, only the (j + 1 J) and (1, Ν) components are 1 and the other components are Let の be a matrix of Ν rows and Ν columns where is 0, and the sum N given as R = P ^k_1 XR for an integer k such that N≥k≥2

 k 1

 Is composed of

 When mapping an OFDM-modulated signal onto subcarriers, the bit strings of each signal sequence divided into N systems are adjacent at N subcarrier periods (N is an integer greater than 1).

 U il

 When the interleaving process is performed in such a manner that the rotation matrix R used for the subcarriers accommodating the user information is represented by N each of the rotation matrix groups {R}.

 k k U The prepared ones are appropriately rearranged and corresponded in order by the N × N subcarrier period. According to this, it is also possible to provide a simple realizing method for generating a matrix used as the above-described rotation matrix.

 [0065] The present invention is also a wireless communication system having the above wireless communication device in the first wireless station,

 The second wireless station includes M (M is an integer of 1 or more) second antenna group, means for individually receiving a wireless signal using the second antenna group,

Each signal system described above, using a signal of a known pattern given to the received signal as a reference signal. Means for separating and demodulating the signal in the column;

 Means for combining all demodulated signal sequences and outputting as user data.

 [0066] As another typical embodiment of the wireless communication method of the present invention,

 A wireless communication method used in a wireless communication system that performs wireless communication using an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of subcarriers,

 In the dividing step, user data to be transmitted is divided into N systems individually for each subcarrier,

 In the conversion step, the information of the n-th (ns is an integer of 1 or more) symbol of the N series of signal sequences in a certain subcarrier is (χ (η), χ (η), } And this s 1 s 2 s N s

 If N-row column vector force x (n) having these as each component, then N-row N-column unit row s

 N (N> 1: N is an integer) obtained by replacing the columns or columns of the unit matrix as appropriate

 R R R

 When the rotation matrix group is expressed as {R} (N ≥ k ≥ l: k is an integer), k R corresponding to each subcarrier

 Using R for a given k, the step of transforming the vector x (n) to R x x (n) is reduced by a small k s k s

 Including at least

 The transmitting means transmits the 减 th component of the converted column vector in each subcarrier from the i-th antenna of the first antenna group.

[0067] As a preferred example, in the conversion step, the signal of the n-th symbol transmitted from the i-th antenna of the first antenna group in each subcarrier is converted into [RX x (n)].

As another preferred example, the second radio station includes M (M is an integer of 1 or more) second antenna groups,

 Individually for each subcarrier,

 Obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group;

 ,

 For an M-by-N matrix H with the transfer function h as the (j, i) -th component, the

 ,

Calculating a conjugate matrix H ^H ,

Calculating a matrix product of the two matrices, i.e., a square matrix H ^H XH of N rows and N columns, Calculating a N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, further comprising:

 In the conversion step, the signal of the n-th symbol transmitted from the i-th antenna of the first antenna group in each subcarrier is converted into [U XR X x (n)].

 [0069] As another preferred example, the second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 N> N,

 Individually for each subcarrier,

 Obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group;

 ,

Calculating an Ermite conjugate matrix H ^H of the M-by-N matrix H having the transfer function h as the (j, i) -th component,

Calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH,

Calculating an N-by-N tuple matrix U for diagonalizing the matrix H ^H XH;

 Further comprising

 In the conversion step, when an N-by-N matrix and an integer j of N≥j≥l, a matrix in which only the (j, j) -th component is 1 and other component powers ^ are represented as T The signal of the n-th symbol transmitted from the i-th antenna (N≥i≥l: i is an integer) of the first antenna group in each subcarrier is converted into [UXTXRX x (n)].

 [0070] Typically, the second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 Separately receiving a radio signal using the second antenna group; separating and demodulating the signals of the respective signal series using a signal of a known pattern given to the received signal as a reference signal. Steps and

Synthesizing all demodulated signal sequences and outputting as user data. The invention's effect

 As described in detail above, according to the present invention, when performing highly efficient wireless communication using MIMO technology, if the transfer function matrix can be estimated with high accuracy, it is equivalent to the E-SDM method. Even when the transfer function matrix cannot be estimated with high accuracy while realizing good characteristics, it is possible to obtain an effect that stable characteristics can be exhibited even in the case where the transfer function matrix cannot be accurately estimated.

 In addition, when MIMO technology is used for the OFDM modulation scheme, the antenna used when transmitting each signal sequence is replaced for each subcarrier, thereby averaging and randomizing errors for each signal sequence, and coding gain in error correction. Can be improved.

 For example, when performing high-efficiency wireless communication using MIMO technology, it becomes possible to equalize the reception characteristics of a plurality of signal sequences to be superimposed and to randomize code errors on a transmission path. In particular, when combined with the E-SDM scheme, the MIMO technology has a property that the reception characteristics tend to vary greatly between the signal sequences to be superimposed. By averaging the errors and randomizing the errors, as a result, the effect of improving the error correction gain and improving the packet error rate characteristics as a whole can be obtained.

 In addition, when the E-SDM scheme is used in combination with the MIMO technique, a large difference occurs in the characteristics of the signal sequence that is usually superimposed. However, this characteristic is made uniform, and as a result, errors for each signal sequence are averaged and averaged. It is possible to provide a simple realization method for randomizing and improving the coding gain in error correction.

 In addition, the number of transmitting antennas is increased from the number of signal sequences to be superimposed, and the MIMO channels that have the number of transmitting antennas have poor neutral characteristics! Processing can also be performed.

 Brief Description of Drawings

 FIG. 1 is a block diagram showing a configuration example of a receiving unit of a second wireless station in the wireless communication system according to the first embodiment of the present invention.

 FIG. 2 is a block diagram showing a configuration example of a transmission unit of first and second wireless stations in the wireless communication system according to the embodiment.

FIG. 3 is a diagram showing transmission units of first and second wireless stations in the wireless communication system according to the embodiment. Block diagram showing a configuration example

 FIG. 4 is a flowchart showing the content of a receiving process of a second wireless station in the wireless communication system according to the embodiment.

 FIG. 5 is a flowchart showing the details of a channel estimation process in a first wireless station in the wireless communication method according to the embodiment.

 FIG. 6 is a flowchart showing processing contents when a second wireless station receives a wireless control packet in the wireless communication method according to the embodiment.

 FIG. 7 is a flowchart showing the details of a channel estimation process in a first wireless station in the wireless communication method according to the embodiment.

 FIG. 8 is a flowchart showing processing content when a second wireless station receives a wireless control packet in the wireless communication method according to the embodiment.

 FIG. 9 is a block diagram showing a configuration example of a transmission / reception unit of a wireless station in the wireless communication system according to the embodiment.

[10] FIG. 10 is a diagram illustrating a configuration example of a transmission unit of the first wireless station according to the second embodiment of the present invention. [11] A diagram showing a configuration example of a receiving unit of a second wireless station according to the embodiment.

[12] FIG. 12 is a diagram showing a second configuration example of the transmitting unit of the first wireless station according to the embodiment.

[13] FIG. 13 is a diagram showing a third configuration example of the transmitting unit of the first wireless station according to the embodiment.

[14] FIG. 14 is a diagram showing a transmission flow of the first wireless station according to the embodiment.

[15] FIG. 15 is a diagram showing a second transmission flow of the first wireless station according to the embodiment.

[16] FIG. 16 is a diagram showing a third transmission flow of the first wireless station according to the embodiment.

[17] FIG. 17 is a diagram illustrating a configuration of a transmission unit of a first wireless station in the related art.

[18] FIG. 18 is a diagram illustrating a configuration of a receiving unit of a second wireless station in the related art.

[19] FIG. 19 is a diagram showing a transmission flow of the first wireless station in the related art.

[20] FIG. 20 is a diagram showing a reception flow of the second wireless station in the related art.

 FIG. 21 is a diagram 1 showing frequency dependence of characteristics of each signal sequence when both OFDM modulation and MIMO technology are used.

FIG. 22 is a diagram illustrating frequency dependence of characteristics of each signal sequence when both OFDM modulation and MIMO technology are used. Explanation of reference numerals

 1 Data division circuit

 2— 1— 2— 3 Preamble assignment circuit

3—1 one 3—3 ···· Modulation circuit

 4 ... Transmission signal conversion circuit # 1

5-1 1-5-4 ... Radio section

 6— 1— 6— 4 · "Antenna

7 Channel estimation circuit

 8Transfer function matrix management circuit 9Matrix calculation circuit # 1

10 ... Matrix operation circuit # 2

11 ... Transmission signal conversion circuit # 2 12 ... Transmission signal conversion circuit # 3 13 ... Transmission signal conversion circuit # 4

21—1-1 21—3 Antenna

 22— 1— 22— 3 Radio section

23… Channel estimation circuit

24 ... Reception signal management circuit

 25: transfer function matrix management circuit 26: matrix operation circuit (reception) # 1 27: matrix operation circuit (reception) # 2 28: hard decision circuit

29… Data synthesis circuit

31— a— 31— b · · · Receiving antenna 32-a-32-b ... Radio section

33— a— 33— b "-FFT circuit

34… Channel estimation circuit

35… Channel separation circuit — 1— a— 36— K a, 36— 1— b— 36— K b… Subcarrier demodulator-a— 37-b ". PZS converter

… Data synthesis circuit

· · · Transfer function interpolation circuit

… Transfer function management circuit # 2

… Matrix operation circuit

... Data division circuit

— A— 43— Conversion circuit

— A— 44— b… Preamble assignment circuit

— 1— a— 45— K a, 45— 1— b— 45— K b… Subcarrier modulation circuit… Transmission signal conversion circuit

-a 47-b "'IFFT circuit

— A— 48— b… Wireless section

 a— 49 b… Transmission antenna

— 1—51—3… Reception antenna

-1 1 52—3… Radio section

… Channel estimation circuit

… Reception signal management circuit

… Transfer function matrix management circuit

… Matrix operation circuit # 2

… Matrix operation circuit # 3

… Hard decision circuit

… Data synthesis circuit

... Data division circuit

— 1— 61— 3… Preamble assignment circuit

— 1— 62— 3… Modulation circuit

... Transmission signal conversion circuit

-1-64-3 ... Radio section 65— 1— 65— 3 ··· Transmit antenna

 66Matrix operation circuit

 67Transfer function matrix management circuit

 68Channel estimation circuit

 69Control information termination circuit

 70Control information generation circuit

 BEST MODE FOR CARRYING OUT THE INVENTION

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

 <First embodiment>

 FIG. 1 is a diagram illustrating a configuration of a receiving unit of a second wireless station in the wireless communication system according to the first embodiment of the present invention. A wireless communication system according to an embodiment of the present invention includes a first wireless station having N (N is greater than 1 !, an integer) or more first antenna groups, and M (M is an integer greater than 1). And a second wireless station having the second antenna group.

 As an example, a case where a transmitting station transmits data of three systems using three transmitting antennas will be described. In the figure, 51-1—51-3 is a receiving antenna, 52-1—52-3 is a radio section, 53 is a channel estimation circuit, 54 is a received signal management circuit, 55 is a transfer function matrix management circuit, and 56 is a matrix operation. Circuits # 2 and 57 are matrix operation circuits # 3 and 58, a hard decision circuit, and 59 is a data synthesis circuit. Although the basic circuit configuration is the same as the conventional receiving unit configuration shown in FIG. 18, the processing contents of the matrix calculation circuits # 2 (56) and # 3 (57) are different.

 For example, as an example, the process performed in the matrix operation circuit # 2 (56) is a process of obtaining the following matrix for the estimated transfer function matrix H.

(1) H ^H : Hermitian conjugate matrix of transfer function matrix H

(2) H ^H XH

(3) (H ^H XH) — matrix inverse of matrix (2)

(4) (H ^H XH) — ¹ XH ^H : Product of matrix (3) and matrix (1)

As a result of these calculations, matrix (H ^H XH) " ¹ XH ^H is input to matrix operation circuit # 3 (57). Power. Also. The matrix operation circuit # 3 (57) obtains the product of this matrix and the received signal level Rx (H ^H XH) ^—1 XH ^H X Rx by calculation.

Similarly, as an example, a process of obtaining the inverse matrix H− ¹ of the transfer function matrix H in the matrix operation circuit # 2 (56) is performed. Further, matrix operation circuit # 2 (56) force inputs the matrix H ¹ for the matrix operation circuit # 3 (57), the matrix operation circuit # 3 (57), the product of this matrix and the received signal vector Rx H— ¹ X Rx is calculated.

Incidentally, these operations ^{((H H XH) - 1} XH H X Rx or H- ¹ X Rx) determines the solution of the transmitted signal vector Tx when it is negligible the term of thermal noise (Equation 1) Equivalent to operation. Therefore, it is of course possible to obtain the transmission signal vector Tx by decomposing these operations or operations equivalent thereto into a plurality of steps and sequentially processing them.

Similarly, as an example, in the matrix operation circuit # 2 (56), for the transmission signal vector Tx (k), the reception signal vector Rx (k), and the matrix operator F, (FX Rx (k) -Tx (k)) ^H X (FX Rx (k)-Tx (k)) Performs processing to find the matrix operator F that is expected to minimize the expected value of a physical quantity over multiple symbols. The matrix F is input to the matrix operation circuit # 3 (57) from the matrix operation circuit # 2 (56), and the product FX of the matrix and the reception signal vector Rx is input to the matrix operation circuit # 3 (57). Rx is obtained by calculation.

[0078] Note that this matrix operator F is known as a matrix used in the MMSE method in the conventional method, and uses a preamble signal of a received signal to perform (FX Rx (k) -Tx (k) ) ^H X (FX Rx (k) -Tx (k)) can be obtained by minimizing it. The hard decision circuit 58 can be selected when the transfer function matrix and each component of the estimated transmission signal vector do not match the transmission signal point which originally takes a discrete value. This is for performing processing for determining a signal at a transmission signal point. This includes, for example, when performing error correction coding and decoding, performing a process of performing error correction using a signal once subjected to soft decision, and determining a signal point as a result. .

FIG. 2 and FIG. 3 are diagrams showing a configuration example of the transmission unit of the first and second wireless stations. In the figure, 60 is a data division circuit, 61-1—61-3 is a preamble assignment circuit, 62-1—62-3 is a modulation circuit, 63 is a transmission signal conversion circuit, and 64-1—64-3 is wireless Section, 65-1—65-3 is transmission un Reference numeral 66 denotes a matrix operation circuit, 67 denotes a transfer function matrix management circuit, 68 denotes a channel estimation circuit, 69 denotes a control information termination circuit, and 60 denotes a control information generation circuit. The configuration of the transmitting side may be the same as the conventional method, but in this figure, the channel estimation circuit 68 or the control information termination circuit 69 and the control information The generation circuit 70 has been added.

 In FIG. 2, when the first wireless station transmits a wireless data packet, it transmits a control signal for requesting transmission of a signal for estimating a transfer function matrix prior to transmission of the wireless data packet. Generate it at 70 and send it. The signal at this time may be transmitted using a single antenna power without necessarily transmitting using a plurality of transmission antennas. In the second radio station, when the control information terminating circuit 19 recognizes that this signal has been received, the control information generating circuit 20 generates a control signal, and outputs the signal to which the three preamble signals are added. Transmit from the transmitting antenna 65-1—65-3. The first radio station receiving this signal inputs the preamble signal to the channel estimation circuit 68 via the radio sections 64-1 to 64-3, and the channel estimation circuit 68 acquires the transfer function matrix H. This is input to the transfer function matrix management circuit 67.

 In FIG. 3, when the first wireless station transmits a wireless data packet, a control signal is generated by the control information generation circuit 70 prior to the transmission, and three preamble signals are added. The signal is transmitted from three transmitting antennas 65-1—65-3. The second radio station inputs the preamble signal to the channel estimation circuit 68 via the radio sections 64-1 to 64-3, and the channel estimation circuit 68 acquires the transfer function matrix H. This information is input to the control information generation circuit 70, and the control information generation circuit 70 generates a control signal including information on the transfer function matrix, and transmits the control signal.

 When the first wireless station recognizes that this signal has been received by the control information terminating circuit 69, it extracts information on the contained transfer function matrix and sends it to the transfer function matrix management circuit 67. input. Note that the control signal including the information on the transfer function matrix may be transmitted from a single antenna, which does not necessarily need to be transmitted using a plurality of transmission antennas.

[0083] Furthermore, a signal defined as a "first control packet" or a "second control packet" It is not necessary to exchange prior to transmission of a wireless data packet.

 As one example, in the case where data is constantly transmitted and received in both directions while using MIMO technology, a transfer function matrix can be acquired every time data is received.

[0084] As another example, IEEE802.11a in 5GHz band (or 2.4GHz band in

The case of a wireless LAN conforming to IEEE802.11g) will be described. MIMO technology is not used in this wireless LAN system, and MIMO technology is expected as an extension in the future. It is possible to transmit and receive signals conforming to IEEE802.11a (or IEEE802.11g).

 In this IEEE802.11a (or IEEE802.11g) compliant system, when a wireless data packet containing user data is transmitted, a receiving station that has succeeded in reception has a relatively reliable ACK (Acknowledgement) signal indicating successful reception. High! Returns wireless control packets using transmission mode. Even when wireless data packets are transmitted using MIMO technology, the viewpoint of stable transmission and reception of control signals does not use MIMO technology for wireless control packet transfer, that is, signal sequences of multiple systems are transmitted on the same frequency channel. It is expected that the data will be forwarded without overlapping. That is, when data communication is continuously performed, it is considered that data (MIMO applied) → ACK (MIMO not applied) → data (MIMO applied) → ACK (MIMO not applied) → repetition.

[0085] In this case, it is ideal that the transfer function matrix H can be estimated in a radio control packet for ACK return without using MIMO technology. In addition, the signal for that is not a change to the existing IEEE802.1 la (or IEEE802.1 lg) compliant wireless LAN air interface, but the method is preferred.

 To achieve this, the OFDM modulation technology used in IEEE802.11a (or IEEE802.11g) compliant systems is used. In the OFDM modulation technology, a plurality of subcarriers are sequentially arranged orthogonally on a frequency axis, and communication is performed using the fast Fourier transform technology.

[0086] When the MIMO technique is applied, a transfer function matrix H is obtained for each subcarrier, and channel separation processing is performed within the same subcarrier. In this case, the value of the transfer function matrix H is different between different subcarriers, but the correlation is stronger between adjacent subcarriers. . Using this characteristic, for example, assuming that the transfer function between the i-th transmitting antenna and the j-th receiving antenna at subcarrier number n is h (n), information transfer for adjacent subcarriers is performed.

 ,

 The following approximation can be performed.

[0087] [Equation ^{6] hj, i (n)} {h j, i (n - 1) + hj, i (n + 1)} / 2 · · · (6)

[0088] [Equation 7] h _j (n) = {h _i (nl) x2 + hj, _i (n + 2) x1} / 3

[0089] [Equation 8] h _{j (i} (n) = (h _{jf i} Cn-2) xi + hj _{) i} (n + 1) X2} / 3-

[0090] Here, Expression (6) is obtained by setting h (to every other subcarrier (that is, two subcarrier periods).

 j, i This can be used to find the transfer function between them if it is known. Equations (7) and (8) are obtained when h (n) is distributed every other subcarrier (ie, every three subcarriers).

 ,

 In addition, it can be used to determine the transfer function between them.

 [0091] In order to utilize this, when transmitting a signal without applying MIMO on the transmitting side, for example, the even subcarrier uses the first transmitting antenna, the odd subcarrier uses the second transmitting antenna, or a multiple of three. Subcarriers that are multiples of 3 + 1 are transmitted using the second transmit antenna, subcarriers that are multiples of 3 + 2 are transmitted using the third transmit antenna, and so on. Part of the elements of the transfer function matrix can be obtained for each, and the remaining elements can be estimated using Equations (6)-(8).

 Note that the same processing can be applied even in the case of four or more subcarrier periods or more (that is, in the case of superimposing four or more signal sequences).

[0092] Further, with respect to the subcarrier at the end (for example, the first subcarrier or the like) that cannot be obtained by interpolation, it may be approximated by another method such as extrapolation. It should be noted that this technique has a proposal for using this subcarrier by interpolation in the past, and it has been reported by Jan Boer et al. In the non-noon document “Jan Boer et. System backwards compatible and coexistence with lla / g at the link level.- ", IEEE802.il-03 / 714r0, September, 2003".

 [0093] However, these are used for channel estimation in a receiving station that receives a signal in which N signal sequences are superimposed, and are used for demodulation processing of the received signal itself.

 In general, the correlation of transfer functions between adjacent subcarriers is not very strong, and demodulation processing using this will significantly degrade the reception characteristics, and is not a very practical technique. Absent. However, if this method is limited to the use of a matrix for the U-transform performed on the transmitting side, no problem occurs in the demodulation process even if the estimation accuracy of the U-transform matrix is low.

 [0094] In other words, the poor estimation accuracy only slightly reduces the large gain obtained by simply applying the present invention, and does not fall below the characteristics when the present invention is not applied.

 If not all wireless stations implement this function, it is preferable to perform negotiation between the wireless stations at the start of communication and notify each other of the signal transmission method when MIMO is not applied. In accordance with the result of the negotiation, the channel estimation processing is adaptively performed using the correlation of the transfer function between adjacent subcarriers.

[0095] FIG. 4 is a diagram showing a reception flow of the second wireless station in the wireless communication system according to the embodiment of the present invention. Also in this figure, the difference from FIG. 20 of the conventional method is only the contents of the matrix calculation process # 2 performed in process S74 and the matrix calculation process # 3 in process S76. As an example, in the processing performed in the matrix operation circuit # 2 (56), H ^H , H ^H XH, (H ^H XH) ⁻¹ are sequentially obtained, and finally (H ^H XH) − is obtained. In the matrix operation circuit # 3 (57), (H ^H XH) ¹ XH ^H X Rx is obtained by calculation! /

[0096] As another example, contact the matrix operation circuit # 2 (56), Te calculated the inverse matrix H ¹ of the transfer function matrix H, the matrix operation circuit # 3 (57), obtained by calculating the H. In addition, the matrix operation circuit # 2 (56) receives! /, And (FX Rx (k) -Tx (k)) ^H X (FX Rx (k) Tx (k)) The matrix operator F, which is expected to minimize the expected value over a plurality of symbols, is obtained, and the matrix operation circuit # 3 (57) can also obtain the FX Rx by the operation.

 On the other hand, the transmission flow of the transmission unit of the first wireless station may be basically the same as that in FIG. 19, but as an example of performing channel estimation on the transmission side, the following points are different. explain.

 FIG. 5 is a diagram showing a channel estimation process in the first wireless station of the wireless communication method according to the embodiment of the present invention. When a wireless data packet to be transmitted is input to the first wireless station (S21), a wireless control packet is transmitted before transmitting the wireless data packet (S22). This requests the second radio station to transmit a radio control packet to which a predetermined preamble signal has been added from each of the plurality of transmission antennas. After the radio control packet waiting process (S23), if the radio control packet is normally received (S24), the signal is received by a plurality of receiving antennas (S25), and the transfer function matrix H is determined by channel estimation. Is calculated (S26). If the wireless control packet has not been normally received in the process S24, the process returns to the process S22 to retransmit the wireless control packet.

 [0098] FIG. 6 is a diagram showing a flow at the time of receiving a radio control packet in the second radio station in the radio communication method according to the embodiment of the present invention. This wireless communication method includes a first wireless station having N (N is an integer greater than 1) or more first antenna groups and a M (M is an integer greater than 1 and an integer) second antenna group. The communication is performed with a second wireless station provided with.

 In FIG. 6, when a signal is received (S31), it is determined whether or not the signal is a wireless control packet (S32). If the signal is a wireless data packet, normal reception processing is performed (S37).

 On the other hand, if the packet is a radio control packet (S32), the signal type is confirmed (S33), and transmission of a radio control packet to which a predetermined preamble signal is added from each of a plurality of transmission antenna cards is requested. If it is (S34), a radio control packet to which a predetermined preamble signal is added is transmitted from each of the plurality of transmission antennas (S35).

 On the other hand, if it is normal control information (S34), normal control information processing is performed (S36).

FIG. 7 is a diagram showing a channel estimation process in the first wireless station of the wireless communication method according to the embodiment of the present invention. In FIG. 7, the radio data to be transmitted is When a data packet is input (S41), a radio control packet to which a known preamble signal is added is transmitted using N transmission antennas before transmitting this radio data packet (S42). After the radio control packet waiting process (S43), if the radio control packet is normally received (S44), the radio control packet is terminated (S45) and stored in this! Information about the transfer function matrix H is extracted and set in the transfer function matrix management circuit on the transmission side (S46). If it is determined in step S44 that the wireless control packet cannot be normally received, the process returns to step S42 to retransmit the wireless control packet.

FIG. 8 is a diagram showing a flow at the time of receiving a wireless control packet in the second wireless station in the wireless communication method according to the embodiment of the present invention. In FIG. 8, when a signal is received (S51), it is determined whether or not the signal is a wireless control packet (S52). If the signal is a wireless data packet, normal reception processing is performed (S58). On the other hand, if the packet is a wireless control packet (S52), the signal type is confirmed (S53) .If the signal requests information on the transfer function matrix (S54), the signal is received by multiple receiving antennas. A transfer function matrix H is obtained by channel estimation using a known preamble pattern for each of the obtained signals (S55). Thereafter, a radio control packet containing the acquired transfer function matrix information is generated and transmitted (S56). On the other hand, in the processing S54, in the case was the normal control information (S54), performs the normal control information processing (S57) ₀

 As described above, in the description of FIGS. 5 to 8, the first wireless station does not necessarily need to transmit the wireless control packet every time data is transmitted. For example, if a certain amount of time has passed since the last time the transfer function was obtained, it may be transmitted as necessary.

 [0102] As an application area of the MIMO technology, extension of a high-speed wireless LAN system using the 5-GHz band and the 2.4-GHz band is currently attracting attention. In such a wireless LAN system, the function of the first wireless station and the function of the second wireless station are generally implemented in one wireless station, and the OFDM modulation method is used.

 Therefore, FIG. 9 shows a configuration of a transmission / reception unit of a wireless station in the wireless communication system according to the embodiment of the present invention. For the sake of simplicity, this figure uses, as an example, a case where both transmission and reception antennas are of two systems (N = M = 2).

[0103] In Fig. 9, 31-a-31-b is a receiving antenna, 32-a-32-b is a radio section, and 33-a-33-b is FFT circuit, 34 is a channel estimation circuit, 35 is a channel separation circuit, 36-1-a—36-Ka and 36-1-b—36-Kb are subcarrier demodulation circuits, and 37-a—37-b is P / S conversion circuit, 38 is a data synthesis circuit, 39 is a transfer function complementer circuit, 40 is a transfer function management circuit # 2, 41 is a matrix operation circuit, 42 is a data division circuit, 43-a-43-b is S / P Conversion circuit, 44-a-44-b is a preamble adding circuit, 45-1-a-45-Ka and 45-1-b-45-Kb are subcarrier modulation circuits, 46 is a transmission signal conversion circuit, 47-a a-47-b indicates an IFFT circuit, 48-a-48-b indicates a radio unit, and 49-a-49_b indicates a transmitting antenna.

 [0104] First, when a signal is received by the receiving antennas (31-a-31-b), the FFT circuit (33-a-32-b) passes through the radio section (32-a-32-b) for each receiving antenna. In a-33-b), the signal for each subcarrier is separated on the frequency axis. The separated signals are input to the channel estimation circuit 34, and the respective transfer function information is obtained from the known preamble signal in the received signal. If the received signal is a signal obtained by superimposing two signal sequences, the channel separation circuit 35 separates the signals of each sequence based on the transfer function information obtained by the channel estimation circuit 34. Then, the result is input to the subcarrier demodulation circuits (36-1-a-36-Ka and 36-1-b-36-Kb).

 [0105] The processing in the subcarrier demodulation circuits (36-1-a-36-Ka and 36-1-b-36-Kb) is performed by estimating a transmission signal for each subcarrier and appropriately performing error correction processing and the like. Is what you do. The demodulated signal, which was separated for each subcarrier, is subjected to normal-to-serial conversion by the P / S converter (37-a-37-b), and data is reproduced by the data synthesizer 38 Is output.

 On the other hand, if the signal sequence is not superimposed on the signal, the channel separation circuit 35 performs processing such as maximum ratio combining on the signals of the respective receiving antennas for each subcarrier, and generates a subcarrier demodulation circuit (36-1-a- 36-Ka). At this time, the information which becomes a part of the transfer function matrix of MIMO is input from the channel estimation circuit 34 to the transfer function complementing circuit 39. The transfer function completion circuit 39 generates and complements the components of the toothless transfer function matrix by an interpolation operation represented by (Equation 6) and the like.

[0106] Information on the transfer function matrix H obtained here is recorded in the transfer function matrix management circuit # 2 (40). This matrix is updated every time a signal is received, and only the latest information is recorded. The matrix operation circuit 41, against the transfer function matrix H, which is managed by the transfer function matrix management circuit 40, H ^H, H ^H XH successively sought, ultimately H ^H that do we determine the eigenvector for the XH H ^H Find a U-diagonal transformation matrix U for XH.

 The processing for transmitting a signal from the wireless station is also divided into a case where two signal sequences are superimposed and transmitted and a case where a single signal is transmitted.

 [0107] In the case where two signals for transmitting user data at high speed are superimposed and transmitted, when the data is input to the data division circuit 42, it is divided into two signal sequences, The P conversion circuit (43-a-43-b) further distributes the signal for each subcarrier. A known preamble signal is added to each subcarrier signal by a preamble adding circuit (44-a-44-b), and a subcarrier modulation circuit (45-1-a-45-Ka and 45-1-ka) is added. b—45-Kb) is subjected to a predetermined modulation and input to the transmission signal conversion circuit 46.

 [0108] The transmission signal conversion circuit 46 generates a signal converted by using the digital conversion matrix for each subcarrier generated by the matrix operation circuit 41, and converts the converted signal into an IFFT circuit (47-a-47- Enter in b). The IFFT circuit (47-a—47-b) converts the signal separated on the frequency axis into a signal on the time axis, and transmits the signal to the transmitting antenna (48-a—48-b) via the radio section (48-a—48-b). 49-a—Sent from 49-b).

 On the other hand, when transmitting one signal, for example, the same signal is input from the data division circuit 42 to the S / P conversion circuit (43-a) and the S / P conversion circuit (43-b). However, the transmission signal conversion circuit 46 converts the signals transmitted from the transmission antenna 49_a into odd subcarriers and the signals transmitted from the transmission antenna 49-b into even subcarriers. -la, 45-3-a, 45-5-a- ·, 45-2-b, 45-4-b, 45-6-b- · Only the signal is valid (that is, 45- 2-a, 45-4-a, 45-6-a '· ·, 45-1-b, 45-3-b, 45-5-b' · · discard signals, IFFT circuit (47- a— Output to 47-b). Other processing is the same as the conventional processing.

In the above processing, if there is a predetermined difference between the transfer function when transmitting a signal from the first wireless station to the second wireless station and the transfer function in the opposite direction, Processing to correct this difference can be added to the transfer function used to acquire the Tutary transformation on the transmitting side. <Second Embodiment>

 Hereinafter, a second embodiment of the present invention will be described. The present embodiment relates to a technique for exchanging antennas used for transmitting each signal sequence for each subcarrier when using the MIMO technique in the OFDM modulation scheme.

 Here, for simplicity of explanation, it is assumed that transmission is performed by superimposing three signal sequences, and an example will be described in which the number of antennas is three or four.

 FIG. 14 is a diagram showing a transmission flow of the first wireless station (transmitting station) in the second embodiment of the present invention.

 When data is input (step S1), the input data is divided into N data sequences (step S2), and a preamble signal is added to each of these signals (step S3), and this is performed. Then, modulation processing is performed individually for each stream (step S4). In the modulated signal, as the transmission signal conversion process # 1, the matrix R corresponding to each subcarrier

 A conversion process for shuffling (exchanging) the correspondence between the signal sequence and the transmitting antenna is performed using k (step S5), and the converted signal is converted to a radio frequency by the radio unit and the signal is transmitted ( Step S6). The reception flow of the second wireless station (receiving station) is the same as that of the conventional method shown in FIG. 20, and there is no difference.

Here, in the conversion process in transmission signal conversion process # 1 (step S5), for example, when the number of signal sequences to be superimposed is 3, the following three matrices R, R, R

 Use 1 2 3.

[0112] [Number 9]

0 0

 0 1 0

 0 1

• · · (9)

[0113] [Number 10]

(Ten)

[0114] [Number 11]

(11) As one example, R for subcarrier # 1 and R for subcarrier # 2

 1 2, R for subcarrier # 3, R for subcarrier # 4, subcarrier

 3 1

 For # 5, perform the conversion while replacing R in the order of '···. The processing here is, for example,

 2

 Transformation R means that # 1 in the signal sequence in ΜΙΜΟ is replaced with # 2, and # 2 is replaced with # 3.

2

 Well, it corresponds to the process of replacing # 3 with # 1. That is, the antenna transmitting each signal sequence is different between adjacent subcarriers like subcarrier # 1 and subcarrier # 2.

 [0115] This rotation matrix is basically obtained by a process in which each row is appropriately replaced with R shown in (Equation 9). As a method of generating such a matrix for a square matrix of Ν rows and Ν columns, for an integer j such that N> j≥l, only the (j + l, j) and (Ι, Ν) components are Let Ν be a matrix of Ν rows and Ν columns where 1 and other components are 0, and for an integer k such that N≥k≥2

 [0116] [Number 12]

R _k = P ^k — χ R _x

• (12) Thus, a total of N matrices can be obtained.

 It should be noted that may be a unit matrix whose rows (or columns) need not be a unit matrix as in equation (9), but may be replaced as appropriate! /.

[0117] Here, when a system based on IEEE802.11a or IEEE802.11g is considered as an existing wireless LAN system, a data bit string with three subcarrier cycles is used for 48 data transmission subcarriers of OFDM modulation. Interleave processing to change the order of.

 [0118] In other words, subcarrier # 1 → subcarrier # 4 → subcarrier # 7 → subcarrier

 # 2 → subcarrier # 5 → subcarrier # 8 → subcarrier # 3 → subcarrier # 6

→ Subcarrier # 9 → · · · Subcarrier # 48 → Subcarrier # 1 · · · The bit sequence of data is arranged in this order. In the above example, when using the rotation matrices of (Equation 9) to (Equation 11), the same rotation matrix is used for subcarrier # 1 and subcarrier # 4. In this case, the effect of the shuffling by the rotation matrix cannot be obtained, and in such a case, a device is required. For example,

 Subcarrier # 1: Use matrix R,

 Subcarrier # 2: using matrix R,

 2

 Subcarrier # 3: using matrix R,

 Three

 Subcarrier # 4: Use matrix R,

 2

 Subcarrier # 5: using matrix R,

 Three

 Subcarrier # 6: Using matrix R,

 Subcarrier # 7: Use matrix R,

 Three

 Subcarrier # 8: Use matrix R

 Subcarrier # 9: Use matrix R,

 2

 Subcarrier # 10: Use matrix R,

 Subcarrier # 11: Use matrix R,

 2

 Subcarrier # 12: Use matrix R,

 Three

[0119] In the order as shown above, using three types of rotation matrices, adjust so as to have 9 subcarrier periods However, adjustment is performed in such a way that the rotation matrices do not overlap in the three subcarrier cycles, which is the interleave cycle. As a result, the effects of the present invention can be obtained even when interleaving is performed.

 FIG. 15 shows a transmission flow of a first wireless station (transmitting station) in one specific example. The difference from the transmission flow shown in FIG. 14 is that transmission signal conversion processing # 2 (step S8) is performed between processing steps S5 and S6. Here, after applying a rotation matrix corresponding to each subcarrier to the transmission signal vector X for each subcarrier in the processing step S5, a process of further applying an individual query transformation matrix for each subcarrier is performed (step S8). . As a result, the transmission signal vector becomes U XRX x. The signal given by each component of this vector for each subcarrier is transmitted from each radio unit and antenna (step S6)

FIG. 16 shows a transmission flow of the first wireless station in one specific example. The difference from the transmission flow shown in FIG. 14 is that transmission signal conversion processing # 3 (step S9) and transmission signal conversion processing # 4 (step S10) are performed between processing steps S5 and S6. is there. Here, after applying the individual rotation matrix for each subcarrier to the transmission signal vector X in the processing step S5, the vector R Xx is multiplied by the matrix given by (Equation 13) (step S9).

 [0122] [Number 13]

(\ 0 0

 0 1 0

 0 0 1

 0 0 ノ

••• (13) With this, for example, to transmit three signal sequences, a column vector of 3 rows and 1 column is converted to a column vector of 4 rows and 1 column. After that, a transmission signal conversion process # 4 for further applying an individual query transformation matrix U for each 4-by-4 subcarrier is performed (step S10). This As a result, the transmission signal vector becomes 11! ^. The signal given by each component of this vector is transmitted from each radio unit and antenna (step S6).

 In addition, steps S5 and S8 in FIG. 15 and steps S5, S9, and S10 in FIG. 16 are processed in order here. Conversion processing may be performed.

 [0123] Note that the rotation matrix described above is one example, and other rotation matrices may be used, or sub-carriers may be made to correspond to sub-carriers in a different order from that described above. Furthermore, since the transfer function matrix H is different for each subcarrier, the corresponding UTF is also individual for each subcarrier. This query transformation matrix is obtained separately from the processing flow shown in FIG. 16, as in the conventional method.

 A configuration example for realizing the above method as a wireless communication device will be described below with reference to the drawings.

 FIG. 10 is a diagram illustrating a configuration example of a transmission unit of the first wireless station according to the present embodiment. In FIG. 10, 1 is a data division circuit, 2−1−2−3 is a preamble adding circuit, 3−1−3−3 is a modulation circuit, 4 is a transmission signal conversion circuit # 1, and 5−1−5−3 is a transmission signal conversion circuit. The radio section, 6- 1-6-3 indicates an antenna.

 When the user data is input to the data division circuit 1, it is divided into three signal sequences in this figure, and each of them is input to the preamble adding circuits 2-1 to 2-3. Here, a different predetermined preamble signal is provided for each signal sequence. The three signal sequences generated by adding the preamble signal are independently subjected to predetermined modulation by the modulation circuits 3-1 to 1-3-3. Here, in order to perform OFDM modulation, each signal sequence is modulated for each subcarrier.

 [0126] These signals are subjected to predetermined conversion for each subcarrier in transmission signal conversion circuit # 1 (4). The converted signal is transmitted from the antenna 6-1-6-3 via the radio section 5-1-5-3.

 [0127] Here, for example, the three matrices R shown in (Equation 9)-(Equation 11)

 1, R

 2. Use R. One three

 As an example, R for subcarrier # 1, R for subcarrier # 2, subkey

1 2 R for carrier # 3, R for subcarrier # 4, and R for subcarrier # 5 Then, perform conversion while replacing R in order of '· ·.

 2

 [0128] In the processing here, for example, the transform R is the signal sequence # 1 in MIMO,

 2

 Corresponding to the process of replacing # 2 with # 3 and # 3 with # 1. In other words, adjacent subcarriers such as subcarrier # 1 and subcarrier # 2 use different antennas for transmitting each signal sequence.

[0129] The signals converted by the transmission signal conversion circuit 4 in this way are transmitted from the antennas 6-1-6-3 via the wireless units 5-1-5-3.

[0130] When the OFDM modulation scheme is used, user data is not included in a plurality of subcarriers! / In some cases, pilot subcarriers accommodating known signals are included, but the numbering here has been described as excluding pilot subcarriers.

FIG. 11 shows a configuration example of a receiving unit of a second wireless station in the wireless communication method according to the present embodiment.

 In Fig. 11, 21-1-21-3 is an antenna, 22-1-22-3 is a radio unit, 23 is a channel estimation circuit, 24 is a received signal management circuit, 25 is a transfer function matrix management circuit, and 26 is a matrix. Arithmetic circuits (reception) # 1, 27 are matrix operation circuits (reception) # 2, 28 are hard decision circuits, and 29 is a data synthesis circuit.

[0132] Via the antennas 21-1 through 21-3, the radio units 22-1 through 22-3 individually perform data reception processing. The received signals are input to the channel estimation circuit 23. Here, an individual transfer function is calculated for each path and for each subcarrier such as a known signal portion included in the received signal, for example, a preamble signal. This information is input to the transfer function matrix management circuit 25 and is managed as a transfer function matrix H. The matrix operation circuit (reception) # 1 (26) performs a matrix operation for preparation for demodulation as necessary. For example, if the matrix is a square matrix, only the inverse of the matrix H, otherwise, the matrix H H, which is the matrix of the Hermitian conjugate of the matrix ^H , and (H ^H XH) the product of ^H H (H H XH) sequentially calculates the ¹ XH ^H. The following description will proceed assuming a non-square matrix.

[0133] The data following the preamble signal or the like is once managed by the reception signal management circuit 24, and the product of the matrix (H ^H XH) —ix H ^{11 and} the reception signal Rx is calculated by a matrix operation circuit (reception). # 2 Ask in (27). The hard decision circuit 28 performs a hard decision process on the obtained signal and sends the signal. Estimate the communication signal. The data combining circuit combines the reproduced signal sequences separated into the respective signal systems, reproduces the user data on the transmission side, and outputs the data. In the above description, other methods including the force MMSE method, the MLD method, and a combination method thereof performed using the ZF method as an example may be used.

 Furthermore, in the embodiment of the present invention, the application in the subcarrier unit, which is mainly described in the case of applying to the OFDM modulation scheme, is possible. Naturally, the application is also possible in the single carrier modulation scheme. It is possible.

 FIG. 12 shows a second configuration example of the transmitting unit of the first wireless station in the wireless communication method according to the present embodiment. In the example shown in FIG. 12, in the data division circuit 1, the preamble adding circuit 2-1 to 2-3, the modulation circuit 3-1 to 3-3, the transmission signal conversion circuit # 1 (4), the radio section 5-1 One 5-3, antenna 6-1-6-3 are the same as those in Fig. 10, and in addition to this, channel estimation circuit 7, transfer function matrix management circuit 8, matrix operation circuit # 1 (9), matrix operation Circuit # 2 (10) and transmission signal conversion circuit # 2 (11) are provided.

 [0135] It should be noted that even in the first wireless station which is to transmit a signal including user data, when receiving a signal from the second wireless station, the signal received by the antenna 6-1-16-3 should be transmitted. Input to the channel estimation circuit 7 via the radio section 5-1-5-3. Here, similarly to the receiving section shown in FIG. 11, a known signal portion included in the received signal, for example, a transfer function such as a preamble signal is calculated for each path and each subcarrier such as a preamble signal.

This information is input to the transfer function matrix management circuit 8, and is managed as a transfer function matrix H for each subcarrier. In the matrix operation circuit # 1 (9), the matrices H ^H and H ^H XH, which are Hermitian conjugate matrices of the matrix H, are sequentially calculated. Based on the results, calculates the matrix operation circuits # 2 (10), the matrix H ^H XH diagonalization possible Yunitari matrix U in each subcarrier.

At this time, the eigenvalue of the (i, i) component of the matrix diagonalized by the unitary transformation matrix is adjusted so that the absolute value of the eigenvalue increases (or decreases) as the value of i is smaller. . Using the digital transformation matrix U for each subcarrier obtained as described above, for the signal output from the transmission signal conversion circuit 4 in the case of FIG. 12, the transmission signal conversion circuit # 2 (11) In this section, the digital transformation process is performed, and this is transmitted via the radio unit 5-1-1-3 and the antenna 6--1-6-3. I believe.

 The processing on the receiving side performs the same processing as in the case of FIG.

FIG. 13 shows a third configuration example of the transmitting unit of the first wireless station in the wireless communication method according to the present embodiment. In the configuration example shown in FIG. 13, the data division circuit 1, the preamble addition circuit 2-1 to 2-3, the modulation circuit 3-1 to 3-3, the transmission signal conversion circuit # 1 (4), the radio section 5 1-5-3, antenna 6-1-6-3, channel estimation circuit 7, transfer function matrix management circuit 8, matrix operation circuit # 1 (9), and matrix operation circuit # 2 (10) are shown in Fig. 12. This is the same as the configuration example shown. In addition, a transmission signal conversion circuit # 3 (12) and a transmission signal conversion circuit # 4 (13) are provided.

 Also, in the configuration examples shown in FIGS. 10 and 12, the radio section 5-1-5-3 and antenna 6-1-6-3, which were three systems, have been expanded to four systems, and the radio section 5 — 4 and antenna 6 — 4 are added. Accordingly, the degree of the matrix processed in the matrix operation circuit # 2 (10) from the channel estimation circuit 7 is partially changed.

 In the configuration example shown in FIG. 13, for the signal output from transmission signal conversion circuit 4, transmission signal conversion circuit # 3 (12) converts the conversion matrix represented by (Equation 13) above. Integrate. The meaning of this operation is to simply convert a transmission vector formed from three components into a transmission vector of four components. The reason why the matrix power is three rows is that the number of superimposed signal sequences of MIMO is three, but the power of antennas for signal transmission is three. In general, if the number of superpositions is M and the number of antennas for signal transmission is N, it is a matrix of N rows and M columns, and the matrix of the upper M rows is a unit matrix of M rows and M columns, and the lower (N-M) columns Becomes a matrix of all zeros. As a result, a transmission signal vector having components corresponding to the number of transmission antennas (that is, the same order as the Tally transformation matrix) is obtained, and the Tx signal conversion circuit # 4 (13) applies the The conversion processing is performed, and this is transmitted via the radio unit 5-1-1-5-4 and the antenna 6-1-6-4. The processing on the receiving side is the same as that in FIG.

Further, also in the configuration example shown in this drawing, a series of processing is individually performed for each subcarrier. The transmission signal conversion circuit # 1 (4) and transmission signal conversion circuit # 2 (11) in FIG. 12 and the transmission signal conversion circuit # 1 (4) and transmission signal conversion circuit # 3 (12) in FIG. Although the signal conversion circuit # 4 (13) is a separate function block, a separate conversion matrix that summarizes these may be created separately, and the conversion processing may be performed collectively in one function block. .

 As described above in detail, according to the present invention, when performing highly efficient wireless communication using MIMO technology, the reception characteristics of a plurality of signal sequences to be superimposed are made uniform, and the signals are placed on a transmission path. Code errors can be randomized. In particular, when combined with the E-SDM scheme using the OFDM modulation scheme, the MIMO technique has a property that large variations in reception characteristics tend to occur between signal sequences to be superimposed. By averaging the reception characteristics for each signal sequence and randomizing the errors, it is possible to improve the error correction gain and to improve the packet error rate characteristics as a whole.

 [0141] Also, each circuit in the transmission unit shown in Fig. 10, each circuit in the reception unit shown in Fig. 11, each circuit in the transmission unit shown in Fig. 12, and each circuit in the transmission unit shown in Fig. 13 are dedicated hardware. It is composed of a memory and a CPU (Central Processing Unit) that can be realized by hardware, and a program (not shown) for realizing the functions of these circuits is loaded into the memory. The function may be realized by executing the function.

 [0142] Also, the functions of the respective circuits in the transmitter shown in FIG. 10, the respective circuits in the receiver shown in FIG. 11, the respective circuits in the transmitter shown in FIG. 12, and the respective circuits in the transmitter shown in FIG. 13 are realized. For this purpose, a computer program is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read and executed by a computer system. Necessary processing may be performed for each circuit in the receiving unit, each circuit in the transmitting unit shown in FIG. 12, and each circuit in the transmitting unit shown in FIG. Here, the “computer system” includes an OS and hardware such as peripheral devices.

[0143] The "computer-readable recording medium" is a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a DVD-ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. That means. Further, a “computer-readable recording medium” is a program that is dynamically stored for a short time, such as a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, it shall include programs that hold programs for a certain period of time, such as volatile memory in a computer system that becomes a server or a client in that case (transmission medium or transmission wave). Further, the above-mentioned program may be a program for realizing a part of the above-mentioned functions, and further, a program which can realize the above-mentioned functions in combination with a program already recorded in a computer system. It may be a difference file (difference program).

 The embodiments described above are all illustrative of the present invention and are not limiting, and the present invention can be embodied in various other modified and modified forms. . Accordingly, the scope of the present invention is defined only by the appended claims and their equivalents.

 Industrial applicability

According to the present invention, when performing highly efficient wireless communication using MIMO technology, if the transfer function matrix can be accurately estimated, good characteristics equivalent to the E-SDM method can be realized. However, even if the transfer function matrix cannot be estimated with high accuracy, the effect can be obtained if stable characteristics can be exhibited.

 In addition, when MIMO technology is used for the OFDM modulation scheme, the antenna used when transmitting each signal sequence is replaced for each subcarrier, thereby averaging and randomizing errors for each signal sequence, and coding gain in error correction. Can be improved. That is, when performing high-efficiency wireless communication using MIMO technology, there is an effect that it is possible to equalize reception characteristics for each of a plurality of signal sequences to be superimposed and to randomize code errors on a transmission path. INDUSTRIAL APPLICABILITY The present invention is used for performing high-speed transmission of a high-speed wireless access system (or wireless LAN system) using a 2.4 GHz band or a 5 GHz band.

Claims

The scope of the claims

 [1] A wireless communication device used in a wireless communication system configured by a first wireless station and a second wireless station,

 The first radio station has N or more first antenna groups (N is an integer greater than 1).

 tx tx

 e,

 Division means for dividing user data to be transmitted into N systems (N ≥ N> 1, where N is an integer);

 tx

 Means for constructing a wireless data packet composed of N series of signal sequences obtained by adding N types of known pattern signals to the user data divided into the N series,

The process of multiplying each of the N series of signal sequences including the known pattern by an individual coefficient is performed a plurality of times with different combinations of coefficients, and the N series of signal sequences multiplied by the coefficient for each combination of coefficients are synthesized. The signal sequence power of the N systems

 tx

 Conversion means for converting to a sequence of numbers;

 Transmitting means for transmitting the signal converted by the conversion means from the first antenna group;

 A wireless communication device comprising:

 [2] The second wireless station includes M (M is an integer greater than 1) second antenna groups, and an i-th antenna in the first antenna group and a second antenna group in the second antenna group. Acquisition means for acquiring a transfer function h between the j-th antenna and an approximate value thereof,

 J, i

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 J, i

Means for calculating a conjugate matrix H ^H ,

Means for calculating a matrix product of the two matrices, that is, a matrix H ^H XH of N rows and N columns; anda means for calculating a unitary matrix U for diagonalizing the matrix H ^H XH, The conversion means is

 Information of the k-th symbol (k is an integer of 1 or more) of the N signal sequences is (x

 One

(k), x (10, ···, x (k)}, the column vector x (k) with each piece of information of the k-th symbol as

 2 N

 A means for calculating a column vector given by the product of the matrix U, i.e., U X x (k),

The i-th row component [UX x (k)] of the column vector UX x (k) is represented by the i-th antenna in the first antenna group. 2. The wireless communication device according to claim 1, further comprising means for transmitting from a wireless communication device.

[3] means for transmitting a first wireless control packet containing control information prior to transmission of the wireless data packet;

 Means for receiving, using N or more antennas, a second radio control packet that is a response to the first radio control packet,

 The acquisition means uses a plurality of signals of known patterns provided to the second wireless control packet, and obtains the j-th (l ≤j≤M, including means for calculating the transfer function h between the antenna and the i-th (l≤N, i is an integer) antenna used for reception by the first radio station

 ,

 The wireless communication device according to claim 2, wherein:

[4] means for transmitting a signal sequence including N known patterns as a first wireless control packet using the N first antenna groups prior to transmission of the wireless data packet;

 Means for receiving a second wireless control packet that is a response to the first wireless control packet;

 Information on the transfer function h between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group contained in the second radio control packet is

 Means for obtaining;

 3. The wireless communication device according to claim 2, comprising:

 [5] In the communication between the radio stations, an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is an integer greater than 1) is used. 3. The wireless communication device according to claim 2, wherein:

[6] From the second wireless station, a wireless control packet containing control information and / or a wireless data packet containing user data, in which a plurality of signal sequences are not superimposed, that is, only one signal sequence, is transmitted. At the time of reception, the js (l≤ks≤K, where ks is an integer) subcarrier used by the second radio station for transmission (j l≤j≤M; j is an integer) a transfer function acquisition method that obtains the transfer function h ^[ks] between the antenna and the i-th (l≤N, i is an integer) antenna used for reception by the first radio station. Step

 6. The wireless communication device according to claim 5, comprising:

[7] The j-th antenna of the second wireless station in a powerful ks '(l≤ks'≤K, ks' is an integer) subcarrier transmitted by the j-th antenna of the second wireless station And the transfer function h ^[ks ′ ^] between the i-th antenna of the first wireless station and ks, transmitted by the j-th antenna of the second wireless station,

The transfer functions h ^[ksl] and h ^[ks2] for the ks subcarrier and the ks subcarrier, where ， ks and ks ≠ ks, (l≤ks≤K, l≤ks≤K, ks, and ks are integers) Transfer function acquisition means to obtain h ^[ks ' ^] by interpolation or external value of

 ,

 6. The wireless communication device according to claim 5, comprising:

[8] The wireless communication apparatus according to claim 6, further comprising means for notifying the second wireless station that the first wireless station has the transfer function acquiring means.

9. The wireless communication apparatus according to claim 7, further comprising means for notifying the second wireless station that the first wireless station has the transfer function acquiring means.

[10] A wireless communication device for receiving a wireless signal from the wireless communication device according to claim 1 in the second wireless station,

 The second wireless station includes M (M is an integer of 1 or more) second antenna group, means for individually receiving a wireless signal using the second antenna group,

 Demodulation means for separating and demodulating each of the received signal sequence signals, using a signal of a known pattern given to the received signal as a reference signal,

 Output means for synthesizing all demodulated signal sequences and outputting as user data.

[11] The demodulation means:

 A transfer function h between an i-th antenna in the first antenna group and a j-th antenna in the second antenna group is defined as a signal of a known pattern given to the received signal as a reference signal. Means for obtaining;

 ,

 A predetermined operation is performed on an M-by-N matrix H having the transfer function h as the (j, i) -th component, and Ν,

Calculating means for obtaining a vector corresponding to the signal point of the transmission signal of the system, the output means, 11. The unit according to claim 10, further comprising: means for combining N transmission signals provided by respective elements of the vector obtained by the operation with all the received symbols and outputting the combined data as the user data. Wireless communication device.

[12] The calculating means,

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 J, i

Means for calculating a conjugate matrix H ^H ,

Means for calculating a matrix product of the two matrices, that is, an N-by-N matrix H ^H XH; and means for calculating an inverse matrix of the matrix H ^H XH, that is, (H ^H XH) ¹

Means for calculating a matrix (H ^H XH) ¹ XH ^H using these,

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

Means for calculating (H ^H XH) ¹ XH ^H X Rx (k) for the received signal level Rx (k) represented by

 12. The wireless communication device according to claim 11, comprising:

[13] The calculating means includes:

For an N-by-N matrix H having the transfer function h as the (j, i) -th component, an inverse matrix Η— ^{1 of the} matrix Η

 J, i

 Means for calculating

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

On the received signal Besotoru Rx (k) represented by the illustrated), H- ¹ X Rx (radio communication apparatus according to claim 11, wherein the means for calculating the k), characterized in that it comprises for.

[14] The calculating means includes:

The transmission signal of the k-th symbol transmitted from the n-th antenna of the first antenna group is denoted by t (k), and the reception of the k-th symbol actually received by the m-th antenna of the second antenna group If a signal is expressed as r (k), (t (k), t (10, ..., t (k)) ^T (T is

 m 1 2 N

Tx (k), (r (k), r (k),---, r (k)) ^T

 1 2

For a received signal vector Rx (k) expressed by: and a matrix operator F, a vector FX Rx (k) —Tx (k) and a vector of Hermitian conjugate of the vector (FX Rx (k) −Tx (k) ) ^H vector product (F X Rx (k) -Tx (k)) Select matrix operator F so that the expected value over multiple symbols of ^H X (FX Rx (k) -Tx (k)) is expected to be minimized Means to

 Means for calculating F X Rx (k) for each symbol;

 12. The wireless communication device according to claim 11, comprising:

15. The wireless communication device according to claim 14, wherein the matrix operator F is obtained by an MMSE (Minimum Mean Square Error) method.

[16] On the second wireless station side,

 Upon receiving a first wireless control packet from the first wireless station,

 The wireless communication device according to claim 10, further comprising: means for transmitting a second wireless control packet including a plurality of known patterns as a response to the first wireless control packet.

[17] On the second wireless station side,

 Upon receiving a first radio control packet containing N known patterns from the first radio station,

 Means for calculating the transfer function h using the signals of the N known patterns;

 Means for transmitting a second radio control packet containing information on the transfer function as a response to the first radio control packet;

 12. The wireless communication device according to claim 11, comprising:

[18] The communication between the radio stations, wherein an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is an integer greater than 1) is used. Item 11. The wireless communication device according to item 10.

[19] On the second wireless station side,

 When transmitting the radio control packet or the radio data packet to the first radio station without superimposing a plurality of signal sequences, a signal of the ks subcarrier is converted to a second signal corresponding to a subcarrier number ks. Transmission means for transmitting using one specified antenna in the antenna group

19. The wireless communication device according to claim 18, comprising:

20. The wireless communication apparatus according to claim 19, further comprising means for notifying the first wireless station that the second wireless station has the transmitting means.

 [21] A wireless communication system having the wireless communication device according to claim 1 on a transmission side and the wireless communication device according to claim 10 on a reception side.

 [22] A wireless communication method for performing communication between the first wireless station and the second wireless station,

 The first radio station has N or more first antenna groups (N is an integer greater than 1).

 tx tx

 e,

 A dividing step of dividing user data to be transmitted into N systems;

 Constructing a wireless data packet composed of N signal sequences obtained by adding N types of known pattern signals to the user data divided into N signals;

 The process of multiplying each of the N series of signal sequences including the known pattern by an individual coefficient is performed a plurality of times with different combinations of coefficients, and the N series of signal sequences multiplied by the coefficient for each combination of coefficients are synthesized. The signal sequence power of the N systems

 tx

 A conversion step for converting to a series of numbers;

 Transmitting the signal converted in the converting step, the first antenna group power transmitting step;

 A wireless communication method comprising:

 [23] The second wireless station includes M (M is an integer greater than 1) second antenna groups, and an i-th antenna in the first antenna group and an i-th antenna in the second antenna group. An obtaining step of obtaining a transfer function h between the j-th antenna and an approximate value thereof,

 J, i

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 J, i

Calculating a conjugate matrix H ^H ;

Calculating a matrix product of the two matrices, i.e., a matrix H ^H XH of N rows and N columns; anda calculating a dictionary matrix U for diagonalizing the matrix H ^H XH, further comprising: The conversion step is

 Information of the k-th symbol (k is an integer of 1 or more) of the N signal sequences is (x

 One

(k), x (10, ···, x (k)}, the column vector x (k) with each piece of information of the k-th symbol as Calculating a column vector given by the product of the matrix U, i.e., UX x (k).

The transmitting step includes:

 23. The method according to claim 22, further comprising transmitting an i-th row component [UX x (k)] of the column vector UX x (k) from an i-th antenna in a first antenna group. Wireless communication method.

[24] transmitting a first wireless control packet containing control information prior to transmitting the wireless data packet;

 Receiving, using N or more antennas, a second radio control packet that is a response to the first radio control packet,

 The obtaining step uses the signals of a plurality of known patterns given to the second wireless control packet, and determines the j-th (l≤ j≤M, where j is an integer) and calculating a transfer function h between the ith antenna (l≤i≤N, i is an integer) used by the first radio station for reception.

 ,

 24. The wireless communication method according to claim 23, wherein:

[25] a step of transmitting a signal sequence including N known patterns as a first wireless control packet using the N first antenna groups before transmitting the wireless data packet;

 Receiving a second wireless control packet that is a response to the first wireless control packet;

 Information on a transfer function h between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group contained in the second radio control packet is represented by:

 Obtaining,

 24. The wireless communication method according to claim 23, comprising:

[26] In the communication between the radio stations, an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is larger than 1 and an integer) is used. 24. The wireless communication method according to claim 23, wherein:

[27] A radio control packet and / or user data containing control information in which a plurality of signal sequences are not superimposed, ie, only one signal sequence, from the second radio station. When receiving a wireless data packet containing a received signal, the second wireless station of the ks (l≤ks≤K, ks is an integer) subcarrier is determined by the reception state of the signal of the known pattern received by each receiving antenna. Transfer function h ^[ks] between the j-th (l≤j≤M, j is an integer) antenna used for transmission and the i-th (l≤N, i is an integer) antenna used for reception by the first wireless station Transfer function acquisition step for acquiring

 27. The wireless communication method according to claim 26, comprising:

[28] The j-th antenna of the second wireless station in a powerful ks '(l≤ks'≤K, ks' is an integer) subcarrier transmitted by the j-th antenna of the second wireless station And the transfer function h ^[ks ′ ^] between the i-th antenna of the first wireless station and ^ks transmitted by the j-th antenna of the second wireless station.

 J, i

 Ks subcarrier with ≠ ks and ks ≠ ks, where l≤ks≤K, l≤ks≤K, ks and ks are integers

1 2 1 2 1 2 1

Or the extrapolation ^{value of the} transfer functions h ^[ksl] and h ^[ks2] with respect to and the ks-th subcarrier

 2 J, i j, i

Transfer function obtaining step to obtain “h ^LKS ”

 J, i

 27. The wireless communication method according to claim 26, comprising:

29. The wireless communication method according to claim 27, further comprising a step of notifying the second wireless station that the transfer function obtaining step is performed on the first wireless station.

 30. The wireless communication method according to claim 28, further comprising a step of notifying the second wireless station that the first wireless station performs the transfer function obtaining step.

 [31] A wireless communication method for receiving a wireless signal transmitted by the wireless communication method according to claim 22 at the second wireless station by V.

 The second radio station includes M (M is an integer of 1 or more) second antenna groups, and individually receives a radio signal using the second antenna group; and A demodulation step of separating and demodulating a signal of each received signal sequence using the signal of the known pattern as a reference signal,

 An output step of synthesizing all demodulated signal sequences and outputting as user data.

[32] The demodulation step includes: A transfer function h between an i-th antenna in the first antenna group and a j-th antenna in the second antenna group is defined as a signal of a known pattern given to the received signal as a reference signal. Obtaining,

 J, i

 A predetermined operation is performed on an M-by-N matrix H having the transfer function h as the (j, i) -th component, and 、

 J, i

 Calculating a vector corresponding to the signal point of the transmission signal of the system, and the output step,

 The method according to claim 31, further comprising: combining N transmission signals provided by respective elements of the vector obtained by the calculation with all the received symbols, and outputting the resultant as the user data. Wireless communication method.

[33] The calculation step includes:

 For an M-by-N matrix H with the transfer function h being the (j, i) -th component, the Hermitian of the matrix Η

 J, i

Calculating a conjugate matrix H ^H ;

Calculating a matrix product of the two matrices, that is, a matrix H ^H XH of N rows and N columns; and calculating an inverse matrix of the matrix H ^H XH, that is, (H ^H XH) ¹ ;

Further calculating a matrix (H ^H XH) ¹ XH ^H using these;

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

(H ^H XH) ¹ XH ^H X Rx (k) for the received signal level Rx (k) expressed by

 33. The wireless communication method according to claim 32, comprising:

[34] The calculation step includes:

For an N-by-N matrix H having the transfer function h as the (j, i) -th component, an inverse matrix Η— ^{1 of the} matrix Η

 J, i

 Calculating

Assuming that the received signal of the k-th symbol actually received by the m-th antenna of the second antenna group is r (k), (r (k), r (k),---, r (k )) ^T (T is a row vector force conversion to a column vector m 1 2

33. The wireless communication method according to claim 32, further comprising: calculating H ¹ X Rx (k) for a received signal vector Rx (k) represented by:

[35] The calculating step includes: The transmission signal of the k-th symbol transmitted from the n-th antenna of the first antenna group is defined as t _n (k), and the transmission signal of the k-th symbol actually received by the m-th antenna of the second antenna group is When the received signal is expressed as r (k), (t (k), t (10, ..., t (k)) ^T (T is

 m 1 2 N

Tx (k), (r (k), r (k),---, r (k)) ^T

 1 2

For a received signal vector Rx (k) expressed by: and a matrix operator F, a vector FX Rx (k) —Tx (k) and a vector of Hermitian conjugate of the vector (FX Rx (k) −Tx (k) ) ^H vector product of (FX Rx (k) -Tx ( k)) H X to the expected value across multiple symbols (FX Rx (k) -Tx ( k)) and the minimization child is expected Selecting a matrix operator F;

 Calculating F X Rx (k) for each symbol;

 33. The wireless communication method according to claim 32, comprising:

36. The wireless communication method according to claim 35, wherein the matrix operator F is obtained by an MMSE (Minimum Mean Square Error) method.

[37] On the second wireless station side,

 Upon receiving a first wireless control packet from the first wireless station,

 32. The wireless communication method according to claim 31, wherein a step of transmitting a second wireless control packet including a plurality of known patterns as a response to the first wireless control packet is executed.

[38] On the second wireless station side,

 Upon receiving a first radio control packet containing N known patterns from the first radio station,

 Step of calculating the transfer function h using the signals of the N known patterns.

 J, i

 And

 Transmitting a second wireless control packet containing information on the transfer function as a response to the first wireless control packet;

 33. The wireless communication method according to claim 32, wherein:

[39] In the communication between the radio stations, an orthogonal frequency division multiplexing (OFDM) modulation method using K subcarriers (K is larger than 1 and an integer) is used. 32. The wireless communication method according to claim 31, wherein:

[40] On the second wireless station side,

 When transmitting the radio control packet or the radio data packet to the first radio station without superimposing a plurality of signal sequences, a signal of the ks subcarrier is converted to a second signal corresponding to a subcarrier number ks. Transmission step of transmitting using one specified antenna in the antenna group

 40. The wireless communication method according to claim 39, wherein:

41. The wireless communication method according to claim 40, further comprising a step of notifying the first wireless station that the second wireless station performs the transmitting step.

[42] A wireless communication device used in a wireless communication system that performs wireless communication using an orthogonal frequency division multiplexing (OFDM) modulation method using a plurality of subcarriers,

 The dividing means divides user data to be transmitted into N systems individually for each subcarrier,

 The conversion means, the information of the n-th (n is an integer of 1 or more) symbol of the N series of signal sequences in a certain subcarrier is (x (n), x (n), ..., χ (n) } And these

 1 s 2 s N s

 Is an N-row column vector force x (n) having as its components an N-by-N identity matrix or s

 Are N (N> 1: N is an integer) types of rotated rows obtained by appropriately replacing the columns of the unit matrix.

 R R R

 When a group of columns is expressed as {R} (N ≥ k ≥ l: k is an integer), a predetermined k R corresponding to each subcarrier

 k means using R for k, at least means for converting the vector x (n) to RX x (n), and ksks means for transmitting the first component of the converted column vector in each subcarrier as described in the first one. Transmit from the i-th antenna of the antenna group

 The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device.

[43] The conversion unit converts the signal of the n-th symbol transmitted from the first antenna of the first antenna group in each subcarrier so as to be [RX x (n)].

 43. The wireless communication device according to claim 42.

[44] The second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 Individually for each subcarrier,

The i-th antenna in the first antenna group and the j-th antenna in the second antenna group Means for obtaining the transfer function h to or from the tena, or an approximation thereof,

 J, l

 For an M-by-N matrix H with the transfer function h as the (j, i) -th component, the

 J, i

Means for calculating a matrix H ^H

Means for calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH, and means for calculating an N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, Further comprising

 The conversion means converts the signal of the n-th symbol transmitted from the i-th antenna of the first antenna group in each subcarrier to be [U XR X x (n)]

 43. The wireless communication device according to claim 42, wherein:

[45] The second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 N> N,

 Individually for each subcarrier,

 Means for obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group,

 J, i

Means for calculating an Ermite conjugate matrix H ^H of the M-by-N matrix H having the transfer function h as the (j, i) -th component,

Means for calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH, and means for calculating an N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, Further comprising

 The conversion means is a matrix having N rows and N columns, and for an integer j such that N≥j≥l, a matrix in which only the (j, j) -th component is 1 and other components are 0 is represented as T The signal of the n-th symbol transmitted from the i-th antenna (N≥i≥l: i is an integer) of the first antenna group in each subcarrier is converted into [UXTXRXx (n)].

 43. The wireless communication device according to claim 42, wherein:

[46] The rotation matrix group {R} is one matrix selected from a matrix obtained by appropriately replacing the columns of the unit matrix of N rows and N columns, and R is defined as an integer j such that N> j≥l On the other hand, 行列 is a matrix with Ν rows and 行列 columns in which only the (j + l, j) and (1, Ν) components are 1 and the other component powers are ^, and an integer N≥k≥2 configuration by the sum of N matrix given as R = P preparative ¹ XR to k Is formed,

 The rotation matrix R used for a subcarrier in which user information is

 k

 Each matrix of the transposed matrix group {R} is rearranged appropriately, and paired in order with N subcarrier periods.

 k

 Responding

 The wireless communication device according to any one of claims 42 to 45, characterized in that:

[47] The rotation matrix group {R} is a row obtained by appropriately replacing the columns of the unit matrix of N rows and N columns.

 k

Let R be one matrix selected from the columns, and for an integer j such that N> j≥l, only the (j + l, j) and (1, Ν) components are 1 and the other component forces ^ the Ν rows Ν columns of the matrix is a [rho, configured by further in a total of N in the matrix to the integer k consisting N≥k≥2 given as R = P preparative ¹ XR

 k 1

 Is formed,

 When mapping an OFDM-modulated signal onto subcarriers, the bit strings of each signal sequence divided into N systems are adjacent at N subcarrier periods (N is an integer greater than 1).

 U il

 When the interleaving process is performed in such a way that the rotation matrix R

 k is the rotation matrix group {R}

 k each matrix is N

 46. The wireless communication device according to claim 42, wherein the U communication devices are rearranged appropriately and correspond to N N sub-carrier periods in order.

[48] The wireless communication method according to claim 22, wherein

 A wireless communication method used in a wireless communication system that performs wireless communication using an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of subcarriers,

 In the dividing step, user data to be transmitted is divided into N systems individually for each subcarrier,

 In the conversion step, the n-th (n

 s is an integer of 1 or more) The symbol information is {χ (η), χ (η), ···, χ (η)} and s 1 s 2 s N s

 If they are N-row column vector force x (n) having these as each component, then N-row, N-column unit row

 s

 N (N> 1: N is an integer) obtained by replacing the columns or columns of the unit matrix as appropriate

 R R R

 When the rotation matrix group is expressed as {R} (N ≥ k ≥ l: k is an integer),

 k R

 Using R for a given k, the step of transforming the vector x (n) into R x x (n) is reduced.

 k s k s

Including at least The transmitting means transmits the 减 th component of the converted column vector in each subcarrier from the i-th antenna of the first antenna group,

 A wireless communication method, comprising:

 [49] The conversion step is characterized in that a signal of an n-th symbol transmitted from an i-th antenna of the first antenna group in each subcarrier is converted into [RX x (n)]. 48. The wireless communication method according to 48.

[50] The second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 Individually for each subcarrier,

 Obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group;

 ,

 For an M-by-N matrix H with the transfer function h as the (j, i) -th component, the

 ,

Calculating a conjugate matrix H ^H ,

Calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH, and calculating an N-by-N columnary matrix U for diagonalizing the matrix H ^H XH, Further comprising

 In the conversion step, a signal of an n-th symbol transmitted from an i-th antenna of the first antenna group in each subcarrier is converted into [U XR X x (n)].

 49. The wireless communication method according to claim 48, wherein:

[51] The second wireless station includes M (M is an integer of 1 or more) second antenna groups,

 N> N,

 Individually for each subcarrier,

 Obtaining a transfer function h or an approximate value thereof between the i-th antenna in the first antenna group and the j-th antenna in the second antenna group;

 ,

Calculating an Ermite conjugate matrix H ^H of the M-by-N matrix H having the transfer function h as the (j, i) -th component,

Calculating a matrix product of the two matrices, i.e., an N-by-N square matrix H ^H XH,

Calculating an N-by-N tuple matrix U for diagonalizing the matrix H ^H XH When,

 Further comprising

 The transforming step includes the (j, j) -th component tx for an N-by-N matrix and an integer j such that

 When a matrix in which only 1 is the other component power ^ is denoted by T, the sub-carriers transmitted from the i-th antenna of the first antenna group (N≥i≥l: i is an integer) Converts tx S signal of n symbols into [UXTXRX x (n)]

 k s i

 49. The wireless communication method according to claim 48, wherein:

[52] The rotation matrix group {R} is a row obtained by appropriately replacing the columns of the unit matrix of N rows and N columns.

 k

Let R be one matrix selected from the columns, and for an integer j such that N> j≥l, only the (j + l, j) and (1, Ν) components are 1 and the other component forces ^ the Ν rows Ν columns of the matrix is a [rho, configured by further in a total of N in the matrix to the integer k consisting N≥k≥2 given as R = P preparative ¹ XR

 k 1

 Is formed,

 The rotation matrix R used for a subcarrier in which user information is

 k

 Each matrix of the transposed matrix group {R} is rearranged appropriately, and paired in order with N subcarrier periods.

 k

 Responding

 The wireless communication method according to any one of claims 48 to 51, characterized in that:

[53] The rotation matrix group {R} is a row obtained by appropriately replacing the columns of the unit matrix of N rows and N columns.

 k

Let R be one matrix selected from the columns, and for an integer j such that N> j≥l, only the (j + l, j) and (1, Ν) components are 1 and the other component forces ^ the Ν rows Ν columns of the matrix is a [rho, configured by further in a total of N in the matrix to the integer k consisting N≥k≥2 given as R = P preparative ¹ XR

 k 1

 Is formed,

 When mapping an OFDM-modulated signal onto subcarriers, the bit strings of each signal sequence divided into N systems are adjacent at N subcarrier periods (N is an integer greater than 1).

 U il

 When the interleaving process is performed in such a manner that the rotation matrix R used for the subcarriers accommodating the user information is represented by N each of the rotation matrix groups {R}.

 52. The wireless communication method according to any one of claims 48 to 51, wherein k k U prepared ones are appropriately rearranged and corresponded in order with N X N subcarrier periods.