JPH09116527A - Data communication system for mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the fluctuation of the receiving level that is caused by the Rayleigh fading and to attain the communication with high reliability. SOLUTION: A 1st convolutional arithmetic circuit 22 applies a convolutional arithmetic operation to a sending station 20 for the sending data dn by means of a pseudo random series a longer than the data dn . Thus the data sn are obtained and sent. A 2nd convolutional arithmetic circuit 35 applies a convolutional arithmetic operation to a receiving station 21 for the receiving data rn that undergone the convolutional arithmetic operation of the circuit 22 by means of a series a*q where the series an is inverted in terms of time and also a complex conjugate is secured. Thus the data un are reproduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a data communication system in a mobile communication system. With the development of computer systems in recent years, the demand for data communication in mobile communication is also increasing. In wireless communication, especially mobile communication, there is a phenomenon called fading in which the characteristics of the propagation path change due to temporal changes in the positions of transmitters and receivers, as well as the positions of reflectors and obstacles that exist in the space that serves as the propagation path for radio waves. Occurs.

Rayleigh fading occurs when a plurality of waves having a relatively small path difference are applied from all directions with the same strength, and fluctuations in received signal strength and phase rotation occur, making stable communication difficult. This is considered to be one of the most important problems in mobile data communication that requires highly reliable communication.

[0003]

2. Description of the Related Art First, the principle of occurrence of Rayleigh fading will be described with reference to FIG. In this FIG.
Reference numeral 11 is an automobile (called a receiving station) equipped with an automobile telephone and is assumed to be moving in the direction of arrow 12.

Rayleigh fading generated in the mobile communication path is 13 for the receiving station 11 moving to the right.
₁ , ..., 13 ₈ , ..., 13 ₁₆ , ..., 13 ₂₅ , ..., 13 _n
As shown in FIG. 4, when signals of similar strength are received from all directions, the angle −f of the incoming wave with respect to the moving direction 12 of the receiving station 11 causes −f in the frequency spectrum diagram. _d ... Doppler frequency that is different as shown by f _k ... f _d occurs.

Since these waves are combined and received at the receiving station 11, the transmitted radio waves having slightly different frequencies are combined and received. In this way, a plurality of waves are combined and received, so that the received signal temporally undergoes envelope fluctuation and phase rotation.

[0006] Conventionally, in performing data communication, in order to eliminate the above-described amplitude fluctuation due to Rayleigh fading, a plurality of signals that have undergone independent fading are received using a plurality of antennas, and among these, the reception strength is A method such as selection diversity for sending a large signal to the demodulator, or equi-ratio combining for combining a plurality of received signals or maximum ratio combining diversity is used.

Since these methods combine a plurality of signals that have undergone fading independently, even if one signal is greatly attenuated, if the other is not attenuated at the same time, the signal can be correctly received. . It is also an effective method because it can be expected to improve the S / N ratio by combining the signals. However, these methods require a plurality of antennas to be installed at a certain interval, which makes it difficult to meet the demand for downsizing of the device.

There is also a method called frequency diversity in which information is transmitted using a plurality of frequencies. This is a method of transmitting signals using a plurality of frequencies separated by a certain degree, which requires a device for transmitting and receiving signals of a plurality of frequencies, and is a very good method from the viewpoint of effective use of frequency resources. is not.

On the other hand, a method using error correction and interleaving is often used. This is to correct an error within the correction capability of the error correction code by making the information redundant by the error correction coding and distributing the error by interleaving. This method has a problem that band spreading or a decrease in information transmission rate occurs due to redundancy of error correction.

[0010]

By the way, in the above-mentioned antenna diversity system, a plurality of antennas must be installed at a certain interval.
There is a problem that it is difficult to meet the demand for miniaturization of the device.

The frequency diversity method requires a device for transmitting and receiving signals of a plurality of frequencies, and is not a very good method from the viewpoint of effective use of frequency resources.

In the system using error correction and interleaving, there is a problem that band spreading or information transmission speed decrease occurs due to redundancy of error correction. Furthermore, in the antenna diversity method and the frequency diversity method, there is a problem that extra information needs to be transmitted or collected in space or frequency than usual, and redundant information needs to be transmitted extra in error correction. there were.

The present invention has been made in view of the above circumstances, and provides a data communication method in a mobile communication system capable of achieving reliable communication by eliminating fluctuations in the reception level due to Rayleigh fading. Is intended.

[0014]

FIG. 1 shows the principle of the present invention.
Show. Data in the mobile communication system shown in FIG.
The communication method is such that the transmitting station 20 and the receiving station 21 that move are
Data transmission, and the feature of the present invention is that the transmitting station 2
0, transmission data d_nFor transmission data d _nThan long
Long pseudo-random sequence a_nPerform the convolution operation using
Data obtained by this_nFirst convolution operation to send
The receiving station 21 includes a circuit 22 and a first convolution operation circuit 2
Received data r that has been subjected to the convolution operation by 2_nFor
Pseudo-random sequence a_nIs inverted in time, and the complex conjugate
Series a^* _qBy performing a convolution operation using
Data u_nAnd a second convolution operation circuit 35 for reproducing
It has been configured.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a data communication system according to the first exemplary embodiment of the present invention.

In FIG. 2, 20 is a transmitting station and 21 is a receiving station. The transmission station 20 includes a convolution operation circuit 22, a modulator (MOD) 23, and an antenna 24.

The convolutional arithmetic circuit 22 comprises a plurality of flip-flops (FF) 2 which form a shift register for sequentially shifting transmission data in accordance with a system clock signal (not shown).
5 to 26, the transmission data supplied to the head FF 25 and the transmission data output from each FF 25 to 26, and the tap coefficients a ₀ , a ₁ , a _N-2 , a _{N- 1 of the} pseudo random sequence.
A plurality of multipliers 27, 28, 29, 30 for multiplying
And an adder 31 for adding the multiplication results of the multipliers 27 to 30.

On the other hand, the receiving station 21 comprises an antenna 33, a demodulator (DEM) 34, and a convolution operation circuit 35. The convolution operation circuit 35 includes a plurality of flip-flops (FF) 36 to 37 that form a shift register that sequentially shifts the reception data demodulated by the demodulator 34.
And the data supplied to the head FF 36 and each FF 36
To 37 and the tap coefficients a _N-1 , a _N-2 , a ₁ , of the pseudo random sequence obtained by temporally inverting the pseudo random sequence used in the convolution operation circuit 22 of the transmitting station 20.
A plurality of multipliers 38, 39, 40, 41 for multiplying with a ₀
And an adder 4 for adding the multiplication results of the respective multipliers 38 to 41
2 is provided.

With such a configuration, the convolution operation of the convolution operation circuit 22 of the transmitting station 20 is performed as follows. _{Let the} transmission data be d _n , the data length is N, the length of the pseudo random sequence (tap coefficient) a _n is M, and the sampling period is T _C.
In addition, for n other than M ≦ N and 0 ≦ n <N, a convolution operation like the following expression (1) is performed under the condition that d _n = 0.

[0020]

(Equation 1)

Transmission data obtained by this convolution:
s _n is the length M + N-1 series. The transmission data s
_{After n} is modulated by the modulator 23, a radio wave is transmitted from the antenna 24.

On the other hand, the convolutional arithmetic circuit of the receiving station 21.
35, the time of the pseudo-random sequence is expressed by the following equation (2).
Inverted (If it is a complex number sequence, the complex conjugate is
Received by the antenna 33 and received by the demodulator 34.
Convolution with demodulated received data sampled
Playback data of length N: u _n
Get.

[0023]

(Equation 2)

Here, a ^* represents a complex conjugate of the complex number a. In addition, the transmitting station 20 sets the size of a block of transmission data (sequence of length M + N−1) in units of several hundred milliseconds to several seconds, and transmits the data, so that the receiving station 21 transmits from several hundred Hz to 1 Hz. Alternatively, only a component having a frequency shift of several Hz or 1 Hz or less can be extracted and demodulated from a signal subjected to Rayleigh fading or Rice fading having a maximum Doppler frequency lower than that.

Next, a second embodiment will be described with reference to FIG. In FIG. 3, reference numeral 45 is a transmitting station and 46 is a receiving station. The transmitting station 45 includes an orthogonal transform circuit 47 and a modulator (MO
D) 48 and an antenna 49.

The orthogonal transform circuit 47 is a serial / parallel transform circuit (S / S) that transforms serial transmission data into a plurality of parallel data.
P) 50, a plurality of parallel data output from the serial / parallel conversion circuit 50, and Hadamard matrices H _M (0, n) and H _M (1, n)
, ..., H _M (N-1, n) and a plurality of multipliers 51,
52 and 53, and an adder 54 that adds the multiplication results of the multipliers 51 to 53.

However, the Hadamard matrix H _M (0, n), H
_{M (1, n), ...} , in _{H M (N-1, n} ), n = 0~ (M-
1). On the other hand, the receiving station 46 has an antenna 55.
, A demodulator (DEM) 56, and an inverse orthogonal transform circuit 57.

The inverse orthogonal transform circuit 57 receives the received data demodulated by the demodulator 56 and the Hadamard matrix H _M similar to that on the transmitting side.
_{(0, n), H M} (1, n), ..., a plurality of multipliers 58, 59, 60 for multiplying the _{H M (N-1, n} ), the multiplication result of each multiplier 58-60 Integration circuits 61 to 63 that integrate and output, and a parallel / serial conversion circuit (P that converts the parallel data output from each integration circuit 61 to 63 into serial data to obtain reproduced data)
/ S) 64.

In such a configuration, the transmitter station 45 directly
The orthogonal transformation of the alternating transformation circuit 47 is performed as follows. Submit
Data is d_nAnd the data length is N. 0 ≦ n <
In the range of N, d _nBe +1 or -1
You. This data is d for the range of N ≦ n <M._n= 0
And extend it to length M and transform Hadamard transform of size M into
Do. In general, this transform can be any orthogonal transform.
No.

[0030]

(Equation 3)

Here, H _M (i, n) represents an element in the i-th row and the n-th column of the Hadamard matrix H _M of degree M whose value is {−1,1}. By this calculation, the output becomes a series of length M. This is carrier-modulated in the modulator 48 and transmitted.

On the other hand, in the receiving station 46, the demodulator 5
6, the carrier demodulation is carried out, and the reception sampling signal r _n obtained by this demodulation is subjected to the inverse orthogonal transform in the inverse orthogonal transform circuit 57 to obtain reproduced data u _n .

[0033]

(Equation 4)

In this equation (4),

[0035]

(Equation 5)

Is an arithmetic expression performed by each of the integrating circuits 61 to 63. Further, in the transmitting station 45, the size of the block of transmission data (sequence of length M) is set in units of several hundred milliseconds to several seconds, and the data is transmitted.
From a signal subjected to Rayleigh fading or Rice fading having a maximum Doppler frequency of several hundred Hz to 1 Hz or less, only a component subjected to frequency shift of several Hz or 1 Hz or less can be extracted and demodulated.

Next, a third embodiment will be described with reference to FIG. However, in the third embodiment shown in FIG. 4, the same parts as those of the first embodiment shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

The third embodiment shown in FIG. 4 corresponds to the first embodiment shown in FIG.
The difference from the embodiment is that when two transmitting stations 20 and 66 having the same configuration as described in the first embodiment communicate at the same frequency, each transmitting station 20 and 66 has a different pseudo-random sequence a _n. By using tap coefficients of b _n and b _n, a pseudo-random sequence obtained by temporally inverting the same pseudo-random sequence used by the transmitting station 20 or 66 which the receiving station 21 wants to receive is used. I am trying to get the data.

That is, when the transmission station 66 other than the transmission station 20 performs the convolution operation by the convolution operation circuit 67, the tap coefficients b ₀ and b _{1 of the} pseudo-random sequence different from those used in the transmission station 20. , B _N-2 , b _N-1 are used.

Then, at the receiving station 21, for example, the transmitting station 20
If you want to receive the data transmitted from the convolution operation circuit 3
5, the pseudo-lander used in the convolutional arithmetic circuit 22 of the transmitting station 20
Tap sequence of a pseudo-random sequence that is a temporally inverted sequence
Number a_N-1, A_N-2, A₁, A ₀Using the transmitting station 20
Play the data sent from.

By doing so, it becomes possible for a large number of users to make a multiple access in which communication is simultaneously performed at the same frequency. Next, a fourth embodiment will be described with reference to FIG. However, the second embodiment shown in FIG. 3 in the fourth embodiment shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

The fourth embodiment shown in FIG. 5 is a block diagram when a plurality of transmitting stations 68 and 69 communicate with the receiving station 70 at the same frequency, and is different from the second embodiment shown in FIG. , Multipliers 73 and 74 for multiplying the output data of the adder 54 of the orthogonal transformation circuit 47 by pseudo random sequences a _n and b _n which are different for each transmitting station are connected between the adder 54 and the modulator 48. In addition, a multiplier 76 for multiplying the data demodulated by the demodulator 56 of the receiving station 70 by the pseudo random sequence a _n or b _n is provided between the demodulator 56 and each of the multipliers 58 to 60 of the inverse orthogonal transform circuit 57. It is connected and configured.

That is, the transmitting station 68 performs the orthogonal transform with the contents of the formula (3) described in the second embodiment changed to the following formula (5).

[0044]

(Equation 6)

However, the other transmitting station 69 uses a _{n of the} equation (5).
Becomes b _n . Further, the receiving station 70 performs the orthogonal transform with the contents of the formula (4) described in the second embodiment changed to the following formula (6).

[0046]

(Equation 7)

In this way, the two transmitting stations respectively a
Multiple access can be performed by multiplying and transmitting different random sequences _n and b _n . Alternatively, a larger number of users can communicate at the same time.

Although the signal of the station modulated by b _n interferes with the user who wants to receive the signal of the station modulated by a _n ,
Since the signal is in a spread state when performing the orthogonal transform, the interference signal becomes smaller than the level of the desired signal and looks like noise.

Next, a fifth embodiment will be described with reference to FIG. However, in the fourth embodiment shown in FIG. 6, the same parts as those in the third embodiment shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

The fifth embodiment shown in FIG. 6 is the third embodiment shown in FIG.
The difference from the embodiment is that the receiving station 77 is connected to a multiplier 78 between the demodulator 34 and the convolution operation circuit 35, and the maximum level detection circuit 79 is connected to the output side of the adder 42 of the convolution operation circuit 35. It has been configured.

That is, the receiving station 77 uses the equation (2) described in the first embodiment as

[0052]

(Equation 8)

With the above contents, transmission data from a plurality of transmission stations 20 and 66 can be extracted. Where T _C is the symbol period. When the maximum Doppler frequency is f _d, the coefficient exp (−j2πf _h T _n ) which is multiplied by the demodulated data r _n of the demodulator 34 in the multiplier 78
F _{h of} is changed from -f _d to f _d at an arbitrary interval, and at this time, the maximum level detection circuit 79 detects the level of the reproduction data output from the adder 42 of the convolution operation circuit 35,
Here, f _h is fixed to the frequency when the level of the reproduction data is maximum, and the reproduction data is obtained.

Next, a sixth embodiment will be described with reference to FIG. However, in the sixth embodiment shown in FIG. 7, the same parts as those in the fourth embodiment shown in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted.

The sixth embodiment shown in FIG. 7 is the fourth embodiment shown in FIG.
The difference from the embodiment is that a receiving station 81 is connected to a multiplier 82 between a multiplier 76 and an inverse orthogonal transform circuit 57, and a maximum level detection circuit is provided on the output side of the parallel / serial conversion circuit 64 of the inverse orthogonal transform circuit 57. It is configured by connecting 83.

That is, the receiving station 81 uses the equation (4) described in the second embodiment,

[0057]

(Equation 9)

With the above contents, transmission data from a plurality of transmission stations 68 and 69 can be extracted. Further, in the case of the formula (6) described in the fourth embodiment, similarly,

[0059]

(Equation 10)

It can be Where T _C is the symbol period. If the maximum Doppler frequency is f _d ,
The f _h of the output data and coefficients are multiplied exp multiplier 76 (-j2πf _h T _n) in the multiplier 82, is changed at any intervals from -f _d to f _d, this time, the inverse orthogonal transform circuit 57 The maximum level detection circuit 83 detects the level of the reproduction data output from the parallel / serial conversion circuit 64, and fixes f _h to the frequency when the level of the reproduction data becomes maximum, and obtains the reproduction data. To do so.

Next, a seventh embodiment will be described with reference to FIG. However, in the seventh embodiment shown in FIG. 8, the same parts as those in the fifth embodiment shown in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

The seventh embodiment shown in FIG. 8 is the fifth embodiment shown in FIG.
The embodiment differs from the reception station 85, the coefficient on the output data of the demodulator _{34 exp (-j2πf K T n)} ~exp (-j
2πf _−K T _n ) is connected to a plurality of convolution operation circuits 35 and 35 ′ via multipliers 86 and 87, and the maximum ratio of data output from the plurality of convolution operation circuits 35 and 35 ′ Maximum ratio combination circuit (MR
C) 88 is provided.

That is, the receiving station 85 will be described in the fifth embodiment.
In equation (7), the f_h= H / [(M + N-
1) T_c], Changing h from −K to K, and u_n
2K + 1 are extracted, and u_{n, -K}, ..., u_{n, 0}, ..., u_{n, K}
And Where K is f_dT _CGreater than (M + N-1)
The smallest integer.

The 2K + 1 signals decomposed in this way are subjected to maximum ratio combining. Using the first L _p bits of the transmitted data as training data, the phase and amplitude of the received data are estimated. That is, at the receiving station 85, d ₀ , d ₁ ,
..., d _Lp-1 is known.

At this time,

[0066]

[Equation 11]

Find Using this,

[0068]

(Equation 12)

Synthesis is carried out as follows. Here, training data length: 16bit, the data length N-L _p: 1008b
it, pseudo-random sequence length M: 32767 (= 2 ¹⁵ −
1), generator polynomial: x ¹⁵ + x + 1, block length M + N +
1: 33790 bit, symbol period T _C : 29 μse
When c (= 1/33790), the system shown in FIG. 8 can perform transmission at about 1 Kbps.

The data and training data are {1,-
1} to obtain d in equation (1).
_n (n = 0, 1, ..., N-1). It is assumed that the pseudo-random sequence a _n is a maximum length shift register sequence having a period 32767 having a primitive polynomial x ¹⁵ + x + 1 on GF (2) as a generating polynomial and is mapped to {1, -1}.

Since (M + N−1) T _C = 1 second, almost 1
Fading can be separated at Hz intervals. When the maximum Doppler frequency of the fading channel is 10 Hz, f _{h is set} to 0, ± 1, ± 2, ..., ± 10, and u _{n, -10, ...,} u
_{Find n, 0, ...,} u _{n, 10} . Furthermore, according to equation (10),
A complex quantity A _h representing the reference phase and the amplitude corresponding to each shift amount (h) is obtained.

Using this as a reference carrier, the data of each shift is demodulated and maximum ratio combining is performed as shown in equation (11). Next, an eighth embodiment will be described with reference to FIG.
However, in the eighth embodiment shown in FIG. 9, the same parts as those in the sixth embodiment shown in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted.

The eighth embodiment shown in FIG. 9 is the sixth embodiment shown in FIG.
The difference from the embodiment is that the receiving station 90 outputs the output data of the multiplier 76 with coefficients exp (−j2πf _K T _n ), exp (−j).
2πf _K−1 T _n ), ..., Exp (−j2πf _−K T _n ), and a plurality of inverse orthogonal transform circuits 57 ′ and 57 ″ are connected to each other via multipliers 91, 92, and 93. Of the inverse orthogonal transform circuits 57, 57 ′, 57 ″, and the maximum ratio combining circuit (M
RC) 94 is provided.

[0074] That is, the receiving station 90, in the formula (8) described in the sixth embodiment, first, a f _h = h / (MT _C), by changing the h from -K to K, the u _n 2K + 1 pieces are extracted to be _{un, -K} , ..., Un _{, 0} , ..., Un _{, K.} Here, K is the smallest integer larger than f _d T _C M. The 2K + 1 signals decomposed in this way are subjected to maximum ratio combining.

Using the first L _p bits of the transmitted data as a training signal, the phase and amplitude of the received data are estimated. That is, in the receiving station 90, d ₀ , d ₁ , ..., D
_{Let Lp-1} be known.

At this time,

[0077]

(Equation 13)

Find Using this,

[0079]

[Equation 14]

Synthesis is carried out as in Here, training data length: 16bit, the data length N-L _p: 1008b
it, Hadamard matrix size M: 32767 (=
2 ¹⁵ ), block length M: 32768 bit, and symbol period T _C : 30.5 μsec (= 1/32768), the system shown in FIG. 9 can perform transmission at about 1 Kbps.

The data and training data are {1,-
1} to obtain d in equation (1).
_n (n = 0, 1, ..., N-1). In this data,
Add 0 elements to make a series of length M, size 32768
Fast Hadamard transform of and send.

Further, when multiple access is performed as in the fourth embodiment shown in FIG. 5, the numerical values are modulated using the maximum length shift register series which is specifically described in the seventh embodiment. Since MT _C = 1 second, fading can be separated at intervals of almost 1 Hz. When the maximum Doppler frequency of the fading channel is 10 Hz, f _h is 0, ± 1, ± 2, ...
As ± 10, un _{, -10, ...,} un _{, 0, ...,} un _{, 10} are obtained.

This processing can be performed by first demodulating the received sampling signal in a random sequence, modulating the frequency shift component, and then performing inverse fast Hadamard transform. Further, the complex quantity A _h representing the reference phase and the amplitude corresponding to each shift amount (h) is obtained according to the equation (12).

Using this as a reference signal, the data of each shift is demodulated and maximum ratio combining is performed as shown in equation (13). When the signal of the equation in the first embodiment described above is represented as a baseband signal,

[0085]

(Equation 15)

It is represented by Here, _pr (t) = {1 0 ≦ t <r, 0 otherwise.

FIG. 1 shows a model of Rayleigh fading.
When 0 is used, the fading wave becomes when the maximum Doppler frequency is f _d.

[0088]

(Equation 16)

It is represented by Here, f _k = f _d cos [2π (k + 0.5) / 4N _r ].

Here, N _r is “total number of received waves /
4 ", which is 8 in FIG. When the transmission signal is input to the receiver through such a fading channel, r (t) = √ (2P) s (t) α (t) + n (t) (16). Here, n (t) is an additive noise component. Here, the received sampling symbol r _n is

[0091]

[Equation 17]

It takes the form of. Here, assuming 2πfT _c << 1,

[0093]

(Equation 18)

Is obtained. Also,

[0095]

[Equation 19]

Is a noise component whose band is limited.
Therefore, the result of applying the equation (7) is as follows. However, it is assumed here that | a _n | = 1.

[0097]

(Equation 20)

It becomes In the first term, f _k −f _h is 1 / (MT
Since it takes a large value only when it is smaller than _C ),
The component that has undergone a specific frequency shift is extracted. The result of the first embodiment is obtained with f _h = 0.

The second term is reduced due to the randomness of the sequence a _q . In addition, by combining these with maximum ratio combining as in the seventh embodiment, a more reliable and stable signal can be obtained.

The result of applying the equation (8) of the sixth embodiment is

[0101]

(Equation 21)

Therefore, in the first term, f _k −f _h is 1 / (MT
Since it takes a large value only when it is smaller than _C ),
The component that has undergone a specific frequency shift is extracted. The second term becomes smaller due to the orthogonality of the Hadamard matrix.

The result of the second embodiment is obtained with f _h = 0. Further, by performing maximum ratio combination of these signals as in the eighth embodiment, a more reliable and stable signal can be obtained.

As described above, according to the present invention, it is possible to separately extract components that have undergone a specific frequency shift with respect to Rayleigh fading that occurs in a normal mobile communication channel, and to eliminate level fluctuations due to fading. Can be reduced. Furthermore, by combining these, highly reliable communication can be achieved.

[0105]

As described above, according to the data communication system in the mobile communication system of the present invention, it is possible to eliminate the fluctuation of the reception level due to Rayleigh fading and achieve highly reliable communication.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of a data communication system according to the first exemplary embodiment of the present invention.

FIG. 3 is a block configuration diagram of a data communication system according to a second embodiment of the present invention.

FIG. 4 is a block diagram of a data communication system according to a third exemplary embodiment of the present invention.

FIG. 5 is a block diagram of a data communication system according to a fourth exemplary embodiment of the present invention.

FIG. 6 is a block configuration diagram of a data communication system according to a fifth embodiment of the present invention.

FIG. 7 is a block configuration diagram of a data communication system according to a sixth embodiment of the present invention.

FIG. 8 is a block configuration diagram of a data communication system according to a seventh embodiment of the present invention.

FIG. 9 is a block configuration diagram of a data communication system according to an eighth embodiment of the present invention.

FIG. 10 is a diagram illustrating the principle of occurrence of Rayleigh fading.

[Explanation of symbols]

20 transmitter station 21 receiver station 22 first convolution operation circuit 35 second convolution operation circuit d _n transmission data a _n pseudo random sequence s _n transmission data after convolution operation r _n reception data a ^* _q pseudo random sequence a _n Sequence u _n reconstructed data in which the time is inverted and the complex conjugate is taken

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideto Furukawa, 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Kazuo Hase, 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Yoshiharu Tajima 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (14)

[Claims] 1. A data communication method in a mobile communication system for performing data communication between a moving transmitting station and a receiving station, wherein the transmitting station uses a pseudo random sequence longer than the transmitting data length for the transmitting data. A first convolution operation circuit that performs a convolution operation is transmitted, and the pseudo random sequence is temporally transmitted to the reception station with respect to the reception data on which the convolution operation is performed by the first convolution operation circuit. A data communication system in a mobile communication system, comprising a second convolution operation circuit that reproduces data by performing a convolution operation using a sequence that has been inverted to and subjected to a complex conjugate. 2. The size of the block of transmission data obtained by subtracting 1 from the value obtained by adding the length of the pseudo-random sequence to the length of the transmission data is the reciprocal of the maximum Doppler frequency of the communication path. From the received signal that has undergone Rayleigh fading or Rice fading in the receiving station by transmitting from the transmitting station by setting from a factor of several times to several tens of times, a frequency equal to or lower than the frequency corresponding to the reciprocal of the length of the transmission data block. 2. The data communication system in a mobile communication system according to claim 1, wherein only the shifted component is extracted and demodulated. 3. A data communication system in a mobile communication system for performing data communication between a moving transmitting station and a receiving station, wherein the transmitting station comprises an orthogonal transformation circuit for performing orthogonal transformation on transmission data, A data communication system in a mobile communication system, wherein a station is provided with an inverse orthogonal transform circuit that reproduces data by performing inverse transform of the orthogonal transform on the received data subjected to the orthogonal transform. 4. A serial / parallel conversion circuit for converting the serial transmission data into parallel data, a plurality of multiplication means for multiplying the parallel data by a Hadamard matrix, and a plurality of multiplication means. And an addition means for adding the multiplication results of the above, and the inverse orthogonal transform circuit includes a plurality of multiplication means for multiplying the received data by the Hadamard matrix,
A plurality of integrating means for integrating the multiplication results of the plurality of multiplying means; and a parallel / serial conversion circuit for converting the parallel data output from the plurality of integrating means into serial data to obtain the reproduction data. The data communication method in the mobile communication system according to claim 3, wherein the data communication method is configured. 5. The size of a block of transmission data whose length is the order of the Hadamard matrix is set to several times to several tens of times the reciprocal of the maximum Doppler frequency of the communication channel, and the block is transmitted from the transmitting station. Wherein the receiving station extracts and demodulates only a component having a frequency shift equal to or higher than a frequency corresponding to the reciprocal of the length of the transmission data block from the received signal subjected to Rayleigh fading or Rice fading. Item 4. A data communication method in the mobile communication system according to Item 4. 6. A plurality of transmitting stations perform convolutional operation of the transmission data using the different pseudo-random sequences in the first convolutional operation circuit and transmit the data, and the receiving station transmits the second convolutional data. The desired data is reproduced by inverting the pseudo-random sequence used in the transmitting station to be received in the convolutional operation circuit in time and performing the convolutional operation using the complex conjugate sequence. A data communication system in a mobile communication system according to claim 1 or 2. 7. The data communication system in a mobile communication system according to claim 6, wherein the plurality of transmitting stations perform data transmission at the same frequency. 8. The transmission station is configured to perform orthogonal transformation by the orthogonal transformation circuit and then modulate with a pseudo random sequence, and the receiving station demodulates received data with the pseudo random sequence and then performs the inverse orthogonal transformation. 4. A data communication system in a mobile communication system according to claim 3, wherein the data is reproduced by performing an inverse orthogonal transformation by a circuit. 9. The multiplication means for multiplying the addition result of the addition means of the orthogonal transformation circuit by a pseudo-random sequence, the received data is multiplied by the pseudo-random sequence, and the multiplication result is obtained by the inverse orthogonal transformation circuit. The data communication system in a mobile communication system according to claim 4, further comprising a multiplication means for outputting to a plurality of multiplication means. 10. The reproduction data is the maximum level of the reproduction data obtained by applying a frequency shift to the reception data at an arbitrary interval to the reception station and inputting the frequency shift to the second convolution operation circuit. 8. A data communication system in a mobile communication system according to claim 6, further comprising means. 11. Reproduced data obtained by applying a frequency shift to the data obtained by demodulating the received data with the pseudo-random sequence at the receiving station and inputting it to the inverse orthogonal transform circuit. 9. A data communication system in a mobile communication system according to claim 8, further comprising means for making reproduction data of the maximum level of the above. 12. The mobile communication according to claim 10, wherein the frequency shift corresponds to the maximum Doppler frequency varying from −f _d to f _d at arbitrary intervals when the maximum Doppler frequency is f _d. Data communication method in the system. 13. The receiving station is provided with a plurality of the second convolutional operation circuits, frequency shift is applied to received data at an arbitrary interval, and the data is input to the plurality of second convolutional operation circuits. 8. A data communication system in a mobile communication system according to claim 6 or 7, further comprising means for maximizing a ratio of some or all of the components having a high intensity among the plurality of data obtained by the above method. 14. The receiving station is provided with a plurality of the inverse orthogonal transform circuits, and frequency shifts are given to data obtained by demodulating received data by the pseudo-random sequence at arbitrary intervals to obtain the plurality of inverse orthogonal transforms. 9. The mobile communication system according to claim 8, further comprising means for inputting to the conversion circuit and performing maximum ratio combination of some components or all components having high intensity among a plurality of data obtained by the input. Data communication method.