JP2009060409A - Data transmission method, data reception method, and data receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data receiver or the like in which inverse matrix processing on a reception side is simplified. <P>SOLUTION: The data receiver receives transmission data B (b<SB>0</SB>, b<SB>1</SB>, ..., b<SB>(M-1)</SB>) (the time length of each data for composing the transmission data B is τ) having a length M and turned into pseudoperiods that are transmitted via a transmission line having known multipath characteristics. The data receiver comprises: a simultaneous equation generation means 16 for generating M pieces of simultaneous equations, based on M reception point data, by regarding that M multpaths occur for each τ; and a simultaneous equation solution means 17 for obtaining b<SB>0</SB>, b<SB>1</SB>, ..., b<SB>(M-1)</SB>in the transmission data B by solving M pieces of simultaneous equations generated by the simultaneous equation generation means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transmission method, a data reception method, and a data reception device, and in particular, a data transmission for obtaining transmission data by generating simultaneous equations using multipaths on the receiving side and solving the simultaneous equations. The present invention relates to a method, a data receiving method, and a data receiving apparatus.

  The wireless communication system to which the transmission method, the transmission device, and the reception device of the present invention are applied is a wireless communication system such as a mobile communication system and a wireless LAN communication system.

  The data includes audio data.

  Suehiro et al. Devised a Suehiro's DFT (SD) method, which is a new information transmission method using a Kronecker product between a row vector and a data vector of a DFT (Discrete Fourier Transform) matrix (see Non-Patent Documents 1 and 2).

  It has been confirmed that this method has about 2.5 times the radio frequency utilization efficiency as compared to the OFDM (Orthogonal Frequency Division Multiplex) method currently used for various communications (see Non-Patent Document 3).

First, the N-dimensional DFT matrix is generated by taking a Kronecker product of each of N (N is a natural number of 4 or more) row vectors and data of length M (M is a natural number of 2 or more). The SD method, which is a transmission method for transmitting and receiving a signal of length M × N, will be described.
(DFT matrix and transmission signal)
An Nth-order DFT (Discrete Fourier Transform) matrix will be described.

N-th order DFT matrix F _N

F _N = [f _N (i, j)] (1)
And Incidentally, the same also N-order inverse DFT matrix _{F N.}

  Here, i is a row number and 0 ≦ i ≦ N−1, and j is a column number and 0 ≦ j ≦ N−1.

F _N (i, j) = exp (2π√−1ij / N) / √N (2)
It is.

Further, as shown in FIG. 1, a variable W _N corresponding to a point obtained by dividing the unit circle into N is defined as follows.

W _N ≡exp (2π√-1) / N (3)

When this W _N is used, the DFT matrix F _N becomes as shown in FIG.

W _N is a rotor, and the following relationship is established.

W _N ^N = e ^j2π = 1 (4)
W _N ^N−k = W _N ^2N−k =... = W _N ^−k (5)
As shown in FIG. 2, the N-th order DFT matrix F _N has _N row vectors of vectors f _{N, 0} , vectors f _{N, 1} ..., Vectors f _{N, N−1} . The row vectors have zero periodic cross-correlation in all shifts (excluding zero shift).

生成された信号Ｓ_０、Ｓ_１・・・、Ｓ_Ｎ−１を送信することにより、複数の送信部から、相関なく、データを送信することができる。なお、送信される信号の長さは、Ｎ×Ｍの長さとなる。 Therefore, as shown in FIG. 3, transmission data # _O (x ₀₀ , x ₀₁ , transmission data # O, transmission data # 1,. _{···, x 0 (M-1} )), the data _{X 1 (x 10, x 11} , ···, x 1 (M-1)) ··· data _{X (N-1) (x} (N- _{1) 0} , x _{(N−1) 1} ,..., X _{(N−1) (M−1)} ) are respectively replaced with a row vector f _{N, 0} , a row vector f _{N, 1} . Signals S ₀ , S ₁ ..., S _N−1 generated as follows are transmitted using vectors f _{N and N−1} .

By transmitting the generated signals S ₀ , S ₁ ..., S _N−1 , data can be transmitted without correlation from a plurality of transmission units. The length of the transmitted signal is N × M.

That is, the signals S ₀ , S _1, ..., S _N−1 have the cyclic cross-correlation of any two signals at all shifts to 0 (zero), so these signals can be obtained by designing an appropriate matched filter. Even if they are transmitted together, it is possible to separate the data strings at the time of reception.
(Matched filter)
Define a vector I _M (1, 0,..., 0) of length M.

を整合する信号とする整合フィルタを用意する。 Here Kronecker product of the vector _{f k (0 ≦ k ≦ N} -1) and _{I M}

A matched filter is prepared for matching signals.

When S _k (0 ≦ k ≦ N−1) is input to the matched filter, M portions from the center of the output become data X _k .

（擬周期信号）
Ｓ_０からＳ_Ｎ−１までを足し合わせた信号をＳ_sumとする。Ｓ_sumは長さＭＮの有限長系列であるため、マルチパスチャネル通過の際に、DFT行列によって得られた周期性を失ってしまう。すると、マッチドフィルタ出力からＸ_ｋ（０≦ｋ≦Ｎ−１）を得ることができなくなる。 Also, S _g when (g ≠ k, 0 ≦ k ≦ N-1, 0 ≦ g ≦ N−1)

(Pseudo-periodic signal)
A signal obtained by adding S ₀ to S _N−1 is defined as S _sum . Since _Ssum is a finite length sequence of length MN, the periodicity obtained by the DFT matrix is lost when passing through the multipath channel. Then, X _k (0 ≦ k ≦ N−1) cannot be obtained from the matched filter output.

  In the case of a periodic infinite signal, the multipath channel does not affect the periodicity of the signal. However, transmitting an infinite length sequence is not practical. Therefore, a pseudo-periodic signal that extracts a necessary length from an infinite-length periodic sequence is introduced.

First, a value L ₂ greater than the assumed multipath delay time is given.
Also, if there is no direct path signal or the power level is very small, the delay time may be negative. Let L ₁ be a value that takes this time into account.
Using these L ₁ and L ₂ , a pseudo-periodic signal as shown in FIG. 4 is generated and transmitted.

Here, the portion corresponding to L ₂ is called a cyclic prefix, and the portion corresponding to L ₁ is called a cyclic postfix. When receiving, it is necessary to remove both before input of the matched filter.
(Pilot signal)
The data string X ₀ is determined as follows with the length as M.

X0=(p0,p1,p2,p3,...,p(L2-1), 0, 0, ..., 0) ・・・・（１１）
ただし、(p₀,p₁,p₂,p₃,...,p_k,...,p_(L2-1) )は、時間kだけ遅れて到達したパスに乗算される複素係数である。 X ₀ = (1,0,0,0, ..., 0) (9)

X0 = (p0, p1, p2, p3, ..., p (L2-1), 0, 0, ..., 0) (11)
Where (p ₀ , p ₁ , p ₂ , p ₃ , ..., p _k , ..., p _(L2-1) ) is a complex coefficient that is multiplied by the path that arrives with a delay of time k. is there.

This p _k is generally calculated using the amplitude coefficient r _k and the phase rotation θ _k ,
p _k = r _k · e ^jθk ··· (12)
It is expressed.

パイロット信号として、長さＭのＺＣＺ等を用いても、マルチパス特性を検出することができる。
（連立方程式）
パイロット信号の挿入によってマルチパス特性を知ることができることを示した。
パイロット以外のデータ信号部分Xk(1<k<N-1)の、それぞれのマッチドフィルタ出力の中心からM個の部分（dk0〜dk(M-1)）は、データとマルチパス特性が以下の式のような関係を示す。 As a pilot signal, a length M ZCZ (zero correlation zone sequence) sequence signal, a length M ZCCZ (zero cross correlation zone sequence) sequence signal, and an M-th order DFT row vector signal can be used. .

Multipath characteristics can also be detected by using a length M ZCZ or the like as a pilot signal.
(Simultaneous equations)
It is shown that the multipath characteristics can be known by inserting pilot signals.
M parts (dk0 to dk (M-1)) from the center of each matched filter output of the non-pilot data signal part Xk (1 <k <N-1) have the following data and multipath characteristics: It shows a relationship like an expression.

(p ₀ , p ₁ , ..., p _L2-2 , p _L2-1 , 0, ..., 0,0,0) ・ x _k0
+ (0, p ₀ , p _1, ..., p _L2-2 , p _L2-1 , 0, ..., 0,0) ・ x _k1
+ (0,0, p ₀ , p ₁ , ..., p _L2-2 , p _L2-1 , 0, ..., 0) ・ x _k2
・
・.
・.
+ (p ₂ , p ₃ , p ₄ , 0, ..., 0,0,0,0, p ₀ , p ₁ ) ・ x _{k (M-2)}
+ (p ₁ , p ₂ , p ₃ , p ₄ , 0, ..., 0,0,0,0, p ₀ ) ・ x _{k (M-1)}
= (d _k0 , d _k1 , d _k2 , ..., d _{k (M-2)} , d _{k (M-1)} ) (13)
When this is expressed using a matrix, the following equation (14) is obtained.

ここで、

here,

とすると、
Ｄ_ｋ＝Ｐ^ｔＸ_ｋ ・・・・（１７）
となる。

Then,
D _k = P ^t X _k (17)
It becomes.

By solving Equation (17) for X _k , transmission data can be obtained on the receiving side.
In order to easily solve this simultaneous equation, it is only necessary to multiply the inverse matrix of P from the left side of both sides of Equation (17).

P ⁻¹ D _k = P ⁻¹ P ^t X _k
= ^T X _k (18)
N. Suehiro, C. Han, T. Imoto, and N. Kuroyanagi, "An information transmission method using Kronecker product", Proceedings of the IASTED International Conference Communication Systems and Networks, pp. 206-209, Sept. 2002. N. Suehiro, C. Han, and T. Imoto, "Very Efficient wireless usage based on pseudo-coherent addition of multipath signals using Kronecker product with rows of DFT matrix", Proceedings of International Simposium on Information Theory, pp.385, June2003 . Naoki Suehiro, Rongzhen Jin, Chenggao Han, Takeshi Hashimoto, "Performance of Very Efficient Wireless Frequency Usage System Using Kronecker Product with Rows of DFT Matrix", Proceedings of 2006 IEEE Information Theory Workshop (ITW'06), pp.526-529, Oct.2006 ..

  In the case of Expression (18) in the SD system, not only in the SD system, but generally, on the receiving side, a simultaneous equation is generated based on the received signal, and the transmission signal is estimated by solving the simultaneous equation. Needs to find an inverse matrix.

  However, there is a problem that as the order increases, the process for obtaining the inverse matrix becomes enormous.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a data transmission method, a data reception method, and a data reception device that simplify the inverse matrix processing on the reception side.

In order to achieve the above object, the data transmission method of the present invention, on the transmission side, transmits time-series transmission data B of length M (b ₀ , b ₁ ,..., B _(M−1) ) (transmission The time length of individual data constituting data B is τ.) Is transmitted via a transmission path with known multipath characteristics, and M−1 multipaths are generated for each τ on the receiving side. As a result, M simultaneous equations are generated based on the M reception point data, and by solving the M simultaneous equations, b ₀ , b ₁ ,. .., B _(M−1) can be obtained.

In order to achieve the above object, according to the data transmission method of the present invention, the number of multipaths in the multipath characteristic (excluding direct waves) is N (N ≦ M−1), Of the length corresponding to Tmax in the front part of the data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ) on the transmitting side. Data or data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ) of the length corresponding to Tmax at the rear of data B (b ₀ , b _01,. ..., B _{0 (M−1)} ) may be added or transmitted before or after transmission.

  In order to achieve the above object, the data transmission method of the present invention is configured such that the data of the length corresponding to the Tmax is the data of the length corresponding to the time longer than the Tmax. can do.

In order to achieve the above object, according to the data transmission method of the present invention, the data corresponding to the length corresponding to Tmax in the front part of data B or the length corresponding to Tmax in the rear part of data B is transmitted on the transmission side. the portion of the data, instead of adding to or after the previous data B, the transmitting side corresponds to the rear of the T ₂ of the data and the data B of the length of the portion corresponding to the T ₁ of the front portion of the data B The length portion data (where T ₁ + T ₂ ≧ Tmax) can be configured to be added after or before the data B.

In order to achieve the above object, the data reception method of the present invention is a transmission data having a length M, which is transmission data transmitted via a transmission path having a known multi-path characteristic, and transmitted in a pseudo-periodic manner. In a data receiving method for receiving data B (b ₀ , b ₁ ,..., B _(M−1) ) (the time length of each data constituting transmission data B is τ), It is assumed that M multipaths are generated for each τ, and M simultaneous equations are generated based on M reception point data, and the simultaneous equation generation step generates the simultaneous equations. In addition, by solving M simultaneous equations, b ₀ , b ₁ ,..., B _(M−1) of transmission data B can be obtained.

In order to achieve the above object, according to the data receiving method of the present invention, the number of multipaths in the multipath characteristic is N (N ≦ M−1), and the maximum delay time with the direct wave on the receiving side is Tmax. In the case where there is a data, the transmitting side has a portion corresponding to the length Tmax of the data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ) or data B (b ₀ , B ₀₁ ,..., B _{0 (M−1)} ), the data of the length corresponding to Tmax at the rear part is represented by data B (b ₀ , b ₀₁ ,..., B _{0. (M-1)} It can be configured to be added and transmitted after or before.

In order to achieve the above object, the data receiving apparatus according to the present invention transmits pseudo-periodic transmission data B (b ₀ , b) transmitted through a transmission path having a known multipath characteristic. ₁ ,..., B _(M−1) ) (the time length of individual data constituting the transmission data B is τ). , Simultaneous equation generating means for generating M simultaneous equations on the basis of M receiving point data on the assumption that M are generated;
Simultaneous equation solving means for obtaining b ₀ , b ₁ ,..., B _(M−1) of transmission data B by solving M simultaneous equations generated by the simultaneous equation generating means. It can be constituted as follows.

In order to achieve the above object, the data receiving apparatus of the present invention is configured such that the number of multipaths (excluding direct waves) in the multipath characteristic is N (N ≦ M−1), , The pseudo-periodic transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) is transmitted on the transmission side. Data of a length corresponding to Tmax at the front part of B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ) or data B (b ₀ , b ₀₁ ,. .., B _{0 (M−1)} ), the data of the length corresponding to the Tmax at the rear of the data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ) Alternatively, it can be configured to be transmission data added before.

In order to achieve the above object, the transmission side has known time-series transmission data B of length M (b ₀ , b ₁ ,..., B _(M−1) ) (transmission data B The time length of each piece of data to be configured is τ.) Is transmitted via a transmission path whose multipath characteristics are unknown, and M−1 multipaths are generated for each τ on the receiving side. And M simultaneous equations are generated on the basis of the M reception point data, and the M simultaneous equations are solved to obtain the multipath characteristics P (p ₀ , p ₁ ,..., P _(M-1) ) can be obtained.

In order to achieve the above object, transmission data transmitted via a transmission path whose multipath characteristics are unknown, and known transmission data B (b _{0) of} length M that is transmitted in a pseudo-periodic manner. , B ₁ ,..., B _(M−1) ) (the time length of each data constituting transmission data B is τ). It is assumed that M-1 occurs every time, and M simultaneous equations generating step for generating M simultaneous equations based on M receiving point data, and M generated in the equation generating step The multipath characteristics P (p ₀ , p ₁ ,..., P _(M−1) ) can be obtained by solving the simultaneous equations.

In order to achieve the above object, known transmission data B (b ₀ , b ₁ ,...) Having a quasi-periodic length M transmitted via a transmission path whose multipath characteristics are unknown. B _{) (M-1)} ) (The time length of each piece of data constituting the transmission data B is τ.) In the data receiving apparatus for receiving, M−1 multipaths are generated for each τ. The simultaneous equation generating means for generating M simultaneous equations based on the M reception point data, and solving the M simultaneous equations generated by the simultaneous equation generating means, And simultaneous equation solving means for obtaining multipath characteristics P (p ₀ , p ₁ ,..., P _(M−1) ).

  According to the present invention, it is possible to provide a data transmission method, a data reception method, and a data reception device that simplify the inverse matrix processing on the reception side.

(Inverse of cyclic matrix)
First, it is shown that the inverse matrix of the circulant matrix can be easily obtained by comparing with the inverse matrix of the normal matrix.

Generally, DFT conversion of vector _{[a 0 a 1 a 2 a} 3 ···· a N-1] transposed vector of _{[a 0 a 1 a 2 a} 3 ···· a N-1] T is It is shown by the middle formula of formula (19) in FIG. Here, [a ₀ a ₁ a ₂ a ₃ ... A _N-1 ] The DFT transform of ^T , [c ₀ c ₁ c ₂ c _3. .. C _N-1 ] ^T

[A ₀ a ₁ a ₂ a ₃ ... A _N-1 ] ^{T obtained} by DFT transform can be transformed as shown in Expression (20).

Transposed vector of the vector one circulating vector of _{[a 0 a 1 a 2 a} 3 ···· a N-1] [a N-1 a 0 a 1 a 2 a 3 ···· a N-2] [A _N-1 a ₀ a ₁ a ₂ a ₃ ... A _N-2 ] The DFT transform of ^T is expressed by equation (21) in FIG.

Also, [a _N-1 a ₀ a ₁ a ₂ a ₃ ... A _N-2 ] ^{T obtained} by DFT transformation can be transformed as shown in Expression (22).

Comparing the left side of equation (18) with the left side of equation (22), [c ₀ c ₁ c ₂ c ₃ ... C _N−1 ] ^T is

となっている。

It has become.

According to this, the vector one-circulated vector of _{[a 0 a 1 a 2 a} 3 ···· a N-1] [a N-1 a 0 a 1 a 2 a 3 ···· a N ₋₂ ] is the second DFT matrix for each element of [c ₀ c ₁ c ₂ c ₃ ... C _N−1 ] ^T in equation (19). Corresponding elements of the column vectors are respectively multiplied.

Next, the circulant matrix A is shown in FIG. 7, and the inverted matrix ^AT of this circulant matrix A is shown in FIG.

FIG. 9 shows the result of DFT transform of the inverted matrix ^AT based on the above consideration.

According to FIG.
F _N A ^T = √NΛ _C F _N (29)
It can be expressed as. Note that Λ _C is a diagonal matrix represented by Expression (28) in FIG.

According to this,
A ^T = F _N ⁻¹ √NΛ _C F _N (30)
And can be transformed.

Also, since the inverted matrix (AB) ^T of the matrix AB is B ^T A ^T , the equation (30) is
A = √NF _N ⁻¹ Λ _C F _N (31)
And can be transformed.

Further, since the inverse matrix (AB) ⁻¹ of the matrix AB is B ⁻¹ A ⁻¹ , the inverse matrix A ⁻¹ of A in the equation (31) is
A ⁻¹ = (1 / √N) F _N ⁻¹ Λ _C F _N (32)
And can be transformed.

According to this, the inverse matrix of the circulant matrix A can be easily obtained by calculating the diagonal matrix Λ _C since F _N and F _N ⁻¹ are known.

Therefore, the inverse matrix of the circulant matrix A can be easily obtained as compared with the inverse matrix of a normal matrix.
(Premise of the present invention)
On the transmission side, time-series transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) of length M shown in FIG. 10 (time length of individual data constituting transmission data B (Time slot) is set to τ), and a pseudo-periodic signal is transmitted.

That is, the transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) is time-series data having a length M, and each data has a τ value for each time slot τ. Sent for a period.

In addition, the pseudo-periodic signal that is pseudo-periodic is a signal (b ₀ , b ₁ ,..., B _(M−1) , b in which L data in the first half of the transmission data B are added to the second half. ₀ , b ₁ ,..., B _(L−1) ;), and each data is transmitted for each time slot τ for a period of τ.

  Note that the pseudo-periodic signal generation method is not limited to this, and can be implemented. However, the length of Lτ must be larger than the maximum delay Tmax of the multipath characteristic.

  Further, it is assumed that the multipath characteristic of the line is known on the receiving side.

  In addition, it is assumed that the multipath characteristic of the line is obtained for each time slot τ.

  It should be noted that there is no problem as long as multipath occurs in each time slot τ. However, if multipath does not occur for each time slot τ, the multipath characteristic is measured assuming that the multipath characteristic of the line is generated for each time slot.

  There are the following various methods for determining that a multipath characteristic of a line is generated for each time slot.

  (1) The average value of the multipath characteristics of the line is calculated for each time slot.

  (2) A vector sum of a plurality of multipath characteristics is calculated for each time slot.

In this way, multipath characteristics can be expressed by amplitude and phase for each time slot.
(Invention of the present application)
Here, for ease of explanation,
In FIG. 10, the case of pseudo-periodic signals with M = 4 and L = 3 and the number of multipath lines = 3 will be described with reference to FIG.

In this case, on the receiving side, a direct wave B (b ₀ , b ₁ , b ₂ , b ₃ , b ₀ , b ₁ , b ₂ ) and a multipath wave having three coefficients p ₀ , p ₁ and p ₂ are generated. Receive.

The multipath wave with the coefficient P ₀ is received after τ of the direct wave B, the multipath wave with the coefficient P ₁ is received 2τ after the direct wave B, and the multipath wave with the coefficient P ₂ is 3τ of the direct wave B. Received later.

Accordingly, as shown in FIG. 11, when the time point when the data b ₀ of the direct wave B is received is t ₀ , the subsequent time points for each τ are t ₁ , t ₂ , t ₃ , t ₄ , t ₅ , t ₆ , t ₇ , t ₈ and t _9, and the received signals at that time are d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₆ , d ₇ , d ₈ and d ₉ The received signal at t ₀ is d ₀ ).
d ₀ , d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₆ , d ₇ , d ₈ and d ₉ are
d ₀ = b ₀
d ₁ = b ₁ + p ₀ b ₀
d ₂ = b ₂ + p ₀ b ₁ + p ₁ b ₀
d ₃ = b ₃ + p ₀ b ₂ + p ₁ b ₁ + p ₂ b ₀
d ₄ = b ₀ + p ₀ b ₃ + p ₁ b ₂ + p ₂ b ₁
d ₅ = b ₁ + p ₀ b ₀ + p ₁ b ₃ + p ₂ b ₂
d ₆ = b ₂ + p ₀ b ₁ + p ₁ b ₀ + p ₂ b ₃
d ₇ = p ₀ b ₂ + p ₁ b ₁ + p ₂ b ₀
d ₈ = p ₁ b ₂ + p ₂ b ₁
d ₉ = p ₂ b ₂
It becomes. Attention is paid to the received data d ₃ , d ₄ , d _5, and d ₆ at time points t ₃ , t ₄ , t _5, and t ₆ (received data within the broken line in FIG. 11).

d ₃ = b ₃ + p ₀ b ₂ + p ₁ b ₁ + p ₂ b ₀ (33)
d ₄ = b ₀ + p ₀ b ₃ + p ₁ b ₂ + p ₂ b ₁ (34)
d ₅ = b ₁ + p ₀ b ₀ + p ₁ b ₃ + p ₂ b ₂ (35)
d ₆ = b ₂ + p ₀ b ₁ + p ₁ b ₀ + p ₂ b ₃ (36)
The received data d ₃ , d ₄ , d ₅ and d ₆ are received signals and can be treated as known. In addition, the multipath characteristics p ₀ , p ₁ and p ₂ are known by assumption. As a result, four undetermined coefficients b ₀ , b ₁ , b ₂ , and b ₃ can be obtained based on these four equations (33) to (36).

  The four formulas (33) to (36) are modified as follows.

d ₃ = p ₂ b ₀ + p ₁ b ₁ + p ₀ b ₂ + b ₃ (37)
d ₄ = b ₀ + p ₂ b ₁ + p ₁ b ₂ + p ₀ b ₃ (38)
d ₅ = p ₀ b ₀ + b ₁ + p ₂ b ₂ + p ₁ b ₃ (39)
d ₆ = p ₁ b ₀ + p ₀ b ₁ + b ₂ + p ₂ b ₃ (40)
Expressions (29) to (32) can be expressed using a matrix as follows.

とすれば、
Ｄ＝ＰＢ ・・・・・（４５）
と表すことができる。

given that,
D = PB (45)
It can be expressed as.

  Therefore, B can be obtained by the following equation.

B = P ⁻¹ D (46)
That is, the transmission data B (b ₀ , b ₁ , b ₂ , b ₃ ) can be obtained from the matrix of received data and the inverse matrix of multipath characteristics.

  Since the matrix of the multipath characteristic is a circulant matrix as shown in the equation (43), it can be easily obtained as described above.

  In the above description, the case where M = 4, L = 3, and the number of multipaths = 3 has been described, but the present invention is not limited to this and can be implemented.

That is, on the transmission side, time-series transmission data B of length M (b ₀ , b ₁ ,..., B _(M−1) ) (time length of individual data constituting transmission data B is expressed as τ. ) Is transmitted via a transmission path having a known multipath characteristic, and the reception side assumes that M−1 multipaths are generated for each τ, and M reception point data Based on, M simultaneous equations are generated, and by solving these M simultaneous equations, b ₀ , b ₁ ,..., B _(M−1) of the transmission data B are obtained. May be.

In addition, when the number of multipaths in the multipath characteristic (excluding direct waves) is N (N ≦ M−1) and the maximum delay time with the direct waves on the receiving side is Tmax, data B ( b ₀ , b ₀₁ ,..., b _{0 (M−1)} ) of the length corresponding to Tmax or data B (b ₀ , b ₀₁ ,. b _{0 (M−1)} ), the data of the length corresponding to Tmax at the rear of the data B (b ₀ , b ₀₁ ,..., b _{0 (M−1)} ) or before It is also possible to transmit it by adding to

  Further, the data corresponding to the length corresponding to Tmax may be data corresponding to the length corresponding to the time equal to or longer than Tmax.

In addition, on the transmission side, instead of adding data having a length corresponding to Tmax in the front part of data B or data having a length corresponding to Tmax in the rear part of data B, before or before data B On the transmission side, the data of the length corresponding to T ₁ at the front of the data B and the data of the length corresponding to T ₂ at the rear of the data B (where T ₁ + T ₂ ≧ Tmax) May be added after or before data B.
(Receiver)
The receiving apparatus of the present invention can be configured as shown in FIG.

  The receiver shown in FIG. 12 includes an antenna 14, a data signal receiving unit 15, simultaneous equation generating means 16, and simultaneous equation solving means 17.

  The communication method can be applied to communication methods such as the SD method and OFDM (Orthogonal Frequency Division Multiplex).

  An outline of the operation of the receiver of FIG. 12 will be described. The received wave affected by the multipath is converted into a baseband signal by the data signal receiving unit 15. The reception signal converted into the baseband signal is generated by the simultaneous equation generation means 16 based on the time-series reception signal as described above. The simultaneous equation solving means 17 obtains a received signal by solving the simultaneous equations generated by the simultaneous equation generating means 16 using known multipath characteristics.

As described above, the present invention makes it possible to generate a cyclic matrix by using the existence of multipath characteristics that have conventionally caused interference in communication, and to estimate a transmission signal by simple processing. be able to.
(Modification 1)
The present invention receives multipath characteristics as known ones, but transmits a pilot signal for multipath characteristic measurement simultaneously with the transmission signal, and detects the multipath characteristics on the receiving side. As described above, it may be received.

  An example of a receiving apparatus in this case is shown in Reception 13.

  The receiver shown in FIG. 13 includes antennas 11 and 14, a pilot signal receiving unit 12, a multipath characteristic measuring unit 13, a data signal receiving unit 15, simultaneous equation generating means 16, and simultaneous equation solving means 17. The antennas 11 and 14 may be a single antenna. In this case, the data signal receiving unit 15 may also serve as the pilot signal receiving unit 12.

  The operation of the receiver of FIG. 1 will be described. The pilot signal receiving unit 12 receives a pilot signal. Based on the transmitted pilot signal and the actually received pilot signal, the multipath characteristic measurement unit 13 estimates the multipath characteristic. Based on the estimated multipath characteristics, the simultaneous equation generating means 16 generates simultaneous equations.

  Note that the pilot signal is a signal different from the data signal and at least a signal that is distinguished from the data signal. As the pilot signal, a signal having high autocorrelation and low cross-correlation with a data signal or the like is used. In addition, the pilot signal to be transmitted can be informed to the reception side in advance, and can be handled as a known signal in the receiver. As a result, on the receiving side, the multipath characteristic can be estimated by comparing the signal that should be originally received with the signal that is actually received.

Note that multipath measurement may be performed prior to communication by transmitting a pilot signal prior to communication. Alternatively, the pilot signal and data signal may be transmitted simultaneously to measure multipath in real time (while communicating). May be performed.
(Modification 2)
In the above description, a cyclic matrix is generated using the existence of a known multipath characteristic, and a transmission signal is estimated by simple processing.

  Similarly, a cyclic matrix is generated from a known transmission signal, and multipath characteristics can be estimated by simple processing.

  That is, in FIG. 10, a case will be described in which there are known pseudo-periodic signals with M = 4 and L = 3, and the number of multipaths of the line estimated from this is 3.

  In this case, as shown in FIG. 11, the reception side receives a direct wave and three multipath waves.

As mentioned above,
d ₃ = b ₃ + p ₀ b ₂ + p ₁ b ₁ + p ₂ b ₀ (33)
d ₄ = b ₀ + p ₀ b ₃ + p ₁ b ₂ + p ₂ b ₁ (34)
d ₅ = b ₁ + p ₀ b ₀ + p ₁ b ₃ + p ₂ b ₂ (35)
d ₆ = b ₂ + p ₀ b ₁ + p ₁ b ₀ + p ₂ b ₃ (36)
It is.

In this expression, received data d ₃ , d ₄ , d ₅ and d ₆ are received signals and can be treated as known. Further, the transmission data b ₀ , b ₁ , b ₂ , b ₃ are known. As a result, three undetermined coefficients p ₀ , p _1, and p ₂ can be obtained based on these four equations (33) to (36).

  Expressions (33) to (36) can be expressed using a matrix as follows.

とすれば、
Ｄ＝Ｂ_１Ｐ_１ ・・・・・（５１）
と表すことができる。

given that,
D = B ₁ P ₁ (51)
It can be expressed as.

Accordingly, P ₁ can be obtained by the following equation.

P ₁ = B ₁ ⁻¹ D (52)
That is, the multipath characteristic P (1, p ₀ , p ₁ , p ₂ ) can be obtained from the matrix of received data and the inverse matrix of transmission signal data.

  Since the matrix of the transmission signal data is a circulant matrix as shown in Equation (49), it can be easily obtained as described above.

  In the above description, the case where M = 4, L = 3, and the number of multipaths = 3 has been described. However, the present modification is not limited to this and can be implemented.

The receiving apparatus of the present invention can be configured as shown in FIG.
(Modification 3)
A case where reception is performed by performing oversampling on the receiving side will be described.

  As described above, when oversampling is not performed, it can be expressed by the following equations (33) to (36).

d ₃ = b ₃ + p ₀ b ₂ + p ₁ b ₁ + p ₂ b ₀ (33)
d ₄ = b ₀ + p ₀ b ₃ + p ₁ b ₂ + p ₂ b ₁ (34)
d ₅ = b ₁ + p ₀ b ₀ + p ₁ b ₃ + p ₂ b ₂ (35)
d ₆ = b ₂ + p ₀ b ₁ + p ₁ b ₀ + p ₂ b ₃ (36)
It is.

For example, when 3 times oversampling is performed, d ₃
Are received in three values: front, middle, and rear. D _3a , d _3b and d _3c
And

Similarly, the values received by oversampling d ₄ , d ₅ and d ₆ are
d _4a , d _4b and d _4c
d _5a , d _5b and d _5c
d _6a , d _6b and d _6c
And

As a result, the multipath characteristics P (1, p _0a , p _1a , p _2a ) are obtained by the equation (52) with d _3a , d _4a and d _5a as a set.

Similarly, with d _3b , d _4b and d _5b as a set, the multipath characteristic P (1, p _0b , p _1b , p _2b ) is obtained by equation (52), and d _3c , d _4c and d _5c are determined. As a set, the multipath characteristics P (1, p _0c , p _1c , p _2c ) are obtained by the equation (52).

  In this way, three multipath characteristics are obtained by three times oversampling.

  Therefore, the majority path logic and average value processing of the three multipath characteristics are performed to obtain the multipath characteristics.

  The present invention is not limited to the specifically disclosed embodiments, and various modifications and embodiments are possible without departing from the scope of the claimed invention. For this reason, the above-described embodiments are merely examples in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by the text of the specification.

It is a figure for demonstrating _WN . This is an Nth-order DFT matrix. It is a diagram for explaining the transmission of data using a row vector of DFT matrix F _N. It is a figure for demonstrating a pseudo-periodic signal. FIG. 4 is a diagram for explaining DFT transformation of a vector [a ₀ a ₁ a ₂ a ₃ ... A _N−1 ] ^T. FIG. 4 is a diagram for explaining DFT transformation of a vector [a _N-1 a ₀ a ₁ a ₂ ... A _N-2 ] ^T. FIG. 6 is a diagram for explaining a cyclic matrix A. 4 is a diagram for explaining an inverted matrix ^AT of a cyclic matrix A. FIG. It is a figure for demonstrating the DFT transformation of the inverted matrix ^AT . It is a figure for demonstrating the pseudo-periodic signal of the time series transmission data B of length M. FIG. It is a figure for demonstrating the received signal in case M = 4, L = 3, and the number of multipaths = 3. It is a figure for demonstrating a receiver (the 1). It is a figure for demonstrating a receiver (the 2).

Explanation of symbols

11, 14 Antenna 12 Pilot signal receiver 13 Multipath characteristic measurement unit
15 data signal receiver 16 simultaneous equation generating means 17 simultaneous equation solving means

Claims (11)

On the transmission side, time-series transmission data B of length M (b ₀ , b ₁ ,..., B _(M−1) ) (time length of individual data constituting transmission data B is τ. .) Through a transmission line with known multipath characteristics,
On the receiving side, it is assumed that M−1 multipaths are generated every τ, and M simultaneous equations are generated based on M receiving point data.
A data transmission method characterized by obtaining b ₀ , b ₁ ,..., B _(M−1) of transmission data B by solving the M simultaneous equations. When the number of multipaths in the multipath characteristic (excluding direct waves) is N (N ≦ M−1) and the maximum delay time with the direct waves on the receiving side is Tmax,
On the transmitting side, data or data B (b ₀ , b ₀₁ ) having a length corresponding to Tmax at the front of data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ). ,..., B _{0 (M−1)} ), the data of the length corresponding to Tmax at the rear part is represented by data B (b ₀ , b ₀₁ ,..., B _{0 (M− 1)} The data transmission method according to claim 1, wherein transmission is performed after or before transmission.   3. The data transmission method according to claim 2, wherein the data having a length corresponding to Tmax is data having a length corresponding to a time equal to or longer than Tmax. Instead of adding data of a length corresponding to Tmax at the front of data B or data of a length corresponding to Tmax at the rear of data B on the transmission side,
On the transmission side, the data of the length corresponding to T ₁ at the front of the data B and the data of the length corresponding to T ₂ at the rear of the data B (where T ₁ + T ₂ ≧ Tmax) are 4. The data transmission method according to claim 2, wherein the data transmission method is added after or before the data B. A transmission data multi-path characteristics are transmitted via known transmission path,擬周initialized to transmit data of length M to be transmitted _{B (b 0, b 1,} ·····, b ( _{M-1) In} a data receiving method for receiving (the time length of each piece of data constituting transmission data B is τ),
A simultaneous equation generating step for generating M simultaneous equations based on M reception point data on the assumption that M-1 multipaths are generated every τ;
Data reception characterized by obtaining b ₀ , b ₁ ,..., B _(M−1) of transmission data B by solving M simultaneous equations generated in the equation generation step. Method. When the number of multipaths in the multipath characteristic is N (N ≦ M−1) and the maximum delay time with the direct wave on the receiving side is Tmax,
On the transmitting side, data or data B (b ₀ , b ₀₁ ) having a length corresponding to Tmax at the front of data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ). ,..., B _{0 (M−1)} ), the data of the length corresponding to Tmax at the rear part is represented by data B (b ₀ , b ₀₁ ,..., B _{0 (M−} 6. The data receiving method according to claim 5, wherein transmission is performed after or before ₁₎ ). Transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) (transmission data) transmitted through a transmission line having a known multipath characteristic and having a pseudo-periodic length M In the data receiving apparatus for receiving the time length of the individual data constituting B, τ)
Simultaneous equation generating means for generating M simultaneous equations on the basis of M reception point data on the assumption that M-1 multipaths are generated every τ;
Simultaneous equation solving means for obtaining b ₀ , b ₁ ,..., B _(M−1) of transmission data B by solving M simultaneous equations generated by the simultaneous equation generating means. A data receiving apparatus. When the number of multipaths in the multipath characteristic (excluding direct waves) is N (N ≦ M−1) and the maximum delay time with the direct waves on the receiving side is Tmax,
The pseudo-periodic transmission data B of length M (b ₀ , b ₁ ,..., B _(M−1) ) is
On the transmitting side, data or data B (b ₀ , b ₀₁ ) having a length corresponding to Tmax at the front of data B (b ₀ , b ₀₁ ,..., B _{0 (M−1)} ). ,..., B _{0 (M−1)} ), the data of the length corresponding to Tmax at the rear part is represented by data B (b ₀ , b ₀₁ ,..., B _{0 (M−} The data receiving apparatus according to claim 7, wherein the data receiving apparatus is transmission data added after or before ₁₎ . On the transmission side, known time-series transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) (time length of individual data constituting transmission data B is τ. Is transmitted via a transmission path whose multipath characteristics are unknown,
On the receiving side, it is assumed that M−1 multipaths are generated every τ, and M simultaneous equations are generated based on M receiving point data.
A data transmission method characterized by obtaining the multipath characteristics P (p ₀ , p ₁ ,..., P _(M−1) ) by solving the M simultaneous equations. Transmission data transmitted via a transmission path with an unknown multipath characteristic, and transmission data B (b ₀ , b ₁ ,. b _(M−1) ) (time length of individual data constituting transmission data B is τ)
A simultaneous equation generating step for generating M simultaneous equations based on M reception point data on the assumption that M-1 multipaths are generated every τ;
Data reception characterized by obtaining multipath characteristics P (p ₀ , p ₁ ,..., P _(M−1) ) by solving M simultaneous equations generated in the equation generation step. Method. Known transmission data B (b ₀ , b ₁ ,..., B _(M−1) ) (pseudo-periodic length M transmitted via a transmission path whose multipath characteristics are unknown. In the data receiving apparatus for receiving, the time length of individual data constituting the transmission data B is τ)
Simultaneous equation generating means for generating M simultaneous equations on the basis of M reception point data on the assumption that M-1 multipaths are generated every τ;
And simultaneous equation solving means for obtaining multipath characteristics P (p ₀ , p ₁ ,..., P _(M−1) ) by solving M simultaneous equations generated by the simultaneous equation generating means. A data receiving apparatus.

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