JP2000244598A - Controller, frequency offset compensator and demodulator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a demodulator capable of obtaining satisfactory bit error rate characteristics even in the case of weak received electric field intensity or violent fluctuation. SOLUTION: The controller is provided with a phase fluctuation quantity calculating part 204 for inputting in-phase and orthogonal components 201 and 202 of a received orthogonal base band signal and a timing signal 203 and outputting a phase fluctuation quantity signal 205 between known symbols, a storage part 206 for inputting the phase fluctuation quantity signal 205 and the timing signal 203 and outputting a phase fluctuation quantity signal 207 between preceding known symbols and a correlation detecting part 208 for inputting the phase fluctuation quantity 205, the preceding phase fluctuation quantity signal 207 and the timing signal 203 and outputting a phase fluctuation quantity correlation signal 209. Thus, the demodulator, with which the bit error rate characteristics are satisfactory even in the case of weak received electric field intensity or violent fluctuation, can be provided by having such a controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device, a frequency offset compensator, and a demodulator used for wireless communication.

[0002]

2. Description of the Related Art As a conventional frequency offset compensation method, there is a technique described in Japanese Patent Application Laid-Open No. 1-196924. This method detects a pilot symbol composed of known data from a received baseband signal at a receiver. This method will be described with reference to FIG.

FIG. 8 shows a temporal change in the phase of a pilot symbol on a complex plane. In FIG. 8, time t =
In mNT (m is a natural number, N is a pilot symbol insertion interval, and T is a symbol period), assuming that the phase fluctuation amount is am from the immediately preceding pilot symbol, if there is a frequency offset, each pilot symbol (P ₀ , P _{0 1} ,
_{P 2, ···, P m-} 1, P m, P m + 1, ···) rotates on a complex plane in a predetermined direction by the rotation amount which is proportional to the frequency offset. Therefore, the amount of rotation is observed, and the phase of the received baseband signal is reversely rotated by an amount corresponding to the phase rotation, thereby compensating for the frequency offset.

[0004]

However, this method has a problem that when the received electric field intensity is weak or the fluctuation is severe, the estimation error of the amount of phase fluctuation becomes large and the bit error rate characteristic is deteriorated.

[0005] The present invention provides a control device for performing control, a frequency offset compensating device for compensating for a frequency offset, or a frequency offset compensating device so as to obtain a good bit error rate characteristic even when the received electric field strength is weak or the fluctuation is severe. It is an object of the invention to provide a demodulation device obtained by using the same.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention is used in a demodulator for wireless communication in which a transmitting side inserts a known signal into transmission data and transmits the data, and a receiving side receives and demodulates the data. Receiving the in-phase component and the quadrature component of the received quadrature baseband signal and the timing signal, and outputting a phase variation signal between known symbols at a certain timing; A storage unit that holds the phase variation signal as an input and outputs a past phase variation signal between known symbols input and retained at a timing earlier than the certain timing as a past phase variation signal, and Correlation detection means for inputting the phase variation signal, the past phase variation signal and the timing signal and outputting a phase variation correlation signal, or A phase variation signal, the past phase variation signal, and an in-phase component and a quadrature component of the received quadrature baseband signal and a timing signal are inputted, and the in-phase component and the quadrature component of the known signal are interpolated, and the phase variation correlation signal and the interpolation are interpolated. Frequency offset calculating means for outputting the in-phase component and the quadrature component of the obtained known signal, or the in-phase component and the quadrature component and the timing signal of the phase variation signal, the past phase variation signal, and the reception quadrature baseband signal. Frequency offset compensation means for inputting and performing frequency offset compensation and outputting a phase variation correlation signal and an in-phase component and a quadrature component of the received quadrature baseband signal after frequency offset compensation. This is a device or a demodulation device using the same.

As a result, it is possible to obtain a control device or a frequency offset compensator or a demodulator using the same that can obtain a good bit error rate characteristic even when the received electric field strength is weak or the fluctuation is severe.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a transmission side inserts a known signal into transmission data and transmits the data.
A phase which is used for a demodulation device of wireless communication which receives and demodulates on a receiving side, which receives an in-phase component and a quadrature component of a received quadrature baseband signal and a timing signal, and outputs a phase variation signal between known symbols at a certain timing. A variation calculating means, a phase variation signal between known symbols that is input and held at a timing earlier than the certain timing and holds the phase variation signal with the phase variation signal and the timing signal as inputs. As a past phase variation signal, and a correlation detection unit that receives the phase variation signal, the past phase variation signal, and the timing signal and outputs a phase variation correlation signal. There is an effect that a good bit error rate characteristic can be obtained even when the reception electric field strength is weak or the fluctuation is severe.

A second aspect of the present invention is used for a radio communication demodulator in which a transmitting side inserts a known signal into transmission data and transmits the data, and a receiving side receives and demodulates the received data. Component and the orthogonal component and a timing signal as input, a phase variation calculating means for outputting a phase variation signal between known symbols at a certain timing, and the phase variation signal with the phase variation signal and the timing signal as inputs. Storage means for holding and outputting as a past phase variation signal a phase variation signal between past known symbols which has been input and held at a timing earlier than the certain timing; and the phase variation signal and the past phase variation A quantity signal and the in-phase component and the quadrature component of the received quadrature baseband signal and the timing signal are input, and the in-phase component and the quadrature component of the known signal are interpolated, A frequency offset compensator comprising frequency variation calculating means for outputting the in-phase component and the quadrature component of the variation correlation signal and the interpolated known signal, and provides a good bit even when the received electric field strength is weak or the variation is severe. It has an effect of obtaining an error rate characteristic.

A third aspect of the present invention is used for a radio communication demodulator in which a transmitting side inserts a known signal into transmission data and transmits the data, and a receiving side receives and demodulates the received data, and uses the same phase of a received quadrature baseband signal. Component and the orthogonal component and a timing signal as input, a phase variation calculating means for outputting a phase variation signal between known symbols at a certain timing, and the phase variation signal with the phase variation signal and the timing signal as inputs. Storage means for holding and outputting as a past phase variation signal a phase variation signal between past known symbols which has been input and held at a timing earlier than the certain timing; and the phase variation signal and the past phase variation Input the in-phase component and the quadrature component of the received quadrature baseband signal and the timing signal to perform frequency offset compensation, A frequency offset compensator comprising a correlation signal and a frequency offset calculating means for outputting an in-phase component and a quadrature component of the received quadrature baseband signal after frequency offset compensation, even when the received electric field strength is weak or the fluctuation is severe. This has the effect of obtaining good bit error rate characteristics.

[0011] The invention described in claim 4 is the first to third aspects of the present invention.
And has an operation of obtaining a good bit error rate characteristic even when the received electric field strength is weak or the fluctuation is severe.

[0012] Further, as in the invention according to the fifth aspect, the demodulation apparatus according to the fourth aspect, characterized in that the wireless communication is of a single carrier system, has the same effect.

[0013] The demodulation device according to the fourth aspect, wherein the wireless communication is of a code division multiplex system as in the invention according to the sixth aspect, has the same effect.

An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a configuration block diagram showing an example of a demodulation device of a wireless communication system according to the present embodiment. In FIG. 1, 101 is an antenna, 1
02 is a reception signal, 103 is a reception radio unit, 104 is an in-phase component of a reception quadrature baseband signal, 105 is a quadrature component of the reception quadrature baseband signal, 106 is a frame / symbol timing detection unit, 107 is a frame / symbol timing signal, Reference numeral 108 denotes a control unit which is a control device, 109 denotes a phase fluctuation amount correlation signal, 110 denotes a detection unit, and 111 denotes a digital signal.

FIG. 2 is a block diagram showing a specific configuration of the control unit 108. 2, reference numeral 201 denotes an in-phase component of a received quadrature baseband signal, 202 denotes a quadrature component of the received quadrature baseband signal, 203 denotes a frame / symbol timing signal, 204 denotes a phase variation calculator, and 205 denotes a phase variation between known symbols. A quantity signal, 206 is a storage unit, 20
Reference numeral 7 denotes a phase fluctuation amount signal between immediately preceding known symbols, 208 denotes a correlation detection unit, and 209 denotes a phase fluctuation amount correlation signal.

FIG. 3 is a conceptual diagram showing an example of a frame configuration of a data symbol and a known symbol with respect to time.
301 is a data symbol and 302 is a known symbol.

The operation of the demodulation device and the control device according to the present embodiment will be described with reference to FIGS. In the demodulation device shown in FIG. 1, a reception signal 102 is received by an antenna 101, a reception radio section 103 receives the reception signal 102, performs quadrature demodulation, and outputs an in-phase component 104 and a quadrature component 105 of the reception quadrature baseband signal. I do.

Frame / symbol timing detector 10
6 receives the in-phase component 104 and the quadrature component 105 of the received quadrature baseband signal, synchronizes the frame and the symbol, and outputs the frame and symbol timing signal 107.

The control unit 108 receives the in-phase component 104 and the quadrature component 105 of the received quadrature baseband signal and the frame / symbol timing signal 107, obtains a phase variation, performs correlation, and outputs a phase variation correlation signal 109. I do.

The detector 110 includes an in-phase component 104 and a quadrature component 105 of the received quadrature baseband signal, a frame / symbol timing signal 107, and a phase variation correlation signal 10.
9 is input to perform detection, and a digital signal 111 is output.

The configuration of the control unit 108 shown in FIG.
This will be specifically described below. In the present embodiment, as shown in FIG. 3, as the frame configuration, a known symbol of one symbol is inserted every eight symbols, that is, one of the symbols of block j of data symbol 301 is inserted.
To 7 are used as an example, and a single carrier system is used as a communication system.

The phase variation calculator 204 receives as input the in-phase component 201 and the quadrature component 202 of the received quadrature baseband signal and the frame / symbol timing signal 203, extracts known symbols, and calculates the phase variation between the known symbols. , Is output as a phase fluctuation amount signal 205 between known symbols.

The storage unit 206 stores the phase fluctuation amount signal 205 between the known symbols and the frame / symbol timing signal 2
03 and the phase fluctuation amount signal 20 at that timing.
5, and outputs a phase variation amount signal 207 between the pilot symbols immediately before that has already been held.

The correlation detection unit 208 receives as input the phase fluctuation signal 205 between known symbols, the phase fluctuation signal 207 between pilot symbols immediately before the phase fluctuation signal 205 between known symbols, and the frame / symbol timing signal 203. , The phase variation signal 205 is compared with the immediately preceding phase variation signal 207, and the correlation value and the like are compared with each other.
9 is output.

The operation of the control unit 108
The phase variation between known symbols in i-2, i-1 and i of FIG. 2 will be described as an example. The phase variation calculator 204 obtains the phase variation θ _i between the known symbols from the known symbols i−1 and i using (Equation 1), and outputs it as a phase variation signal 205 between the known symbols.

[0027]

(Equation 1)

Here, X _i−1 is the i of the known symbol 302
-1 is the in-phase component of the received signal, and Y _i-1 is the known symbol 30.
X _i is the in-phase component of the i received signal of the known symbol 302, and Y _i is the quadrature component of the i received signal of the known symbol 302.

The storage unit 206 stores the known symbols i-1, i
Held by entering the phase deviation theta _i between known symbols obtained from, already held, the phase between the known symbols determined from known symbol i-2, i-1 obtained by (Equation 2) The variation θ _i−1 is output as the phase variation signal 207 between the immediately preceding known symbols.

[0030]

(Equation 2)

Where X _i−2 is _i of the known symbol 302
-2, the in-phase component of the received signal of Y _-2, the known symbol 30
2 i-2 is the orthogonal component of the received signal.

The correlation detecting section 208 outputs the known symbol 302
Phase variation amount θ between known symbols obtained from i−1 and i
_i , the phase fluctuation amount θ _i−1 between known symbols obtained from i−2 and i−1 of the known symbol 302 is input, and θ _i , θ
_i-1 are compared, and for example, (Equation 3) is
09, which is received by the detection unit 110 or a CPU unit (not shown) and used for processing data symbols.

[0033]

(Equation 3)

Thus, even when the received electric field strength is weak or fluctuates drastically, it is possible to obtain a good bit error rate characteristic with respect to the carrier power to noise power ratio.

As described above, by configuring the control device as shown in FIG. 2, appropriate control can be performed even when the received electric field strength is weak or the fluctuation is severe, and when the received electric field strength is weak or the fluctuation is small. Even in severe cases, good bit error rate characteristics can be obtained. By using such a control device as a control unit as shown in FIG. 1,
A demodulation device with good bit error rate characteristics can be obtained.

In this embodiment, the frame configuration has been described with reference to FIG. 3. However, the present invention is not limited to this. The communication system has been described as a single carrier system, but a code division multiple access system is used. Has the same effect.

(Embodiment 2) FIG. 4 is a configuration block diagram showing an example of a demodulation device of a radio communication system according to the present embodiment. In FIG. 4, reference numeral 401 denotes an antenna,
02 is a reception signal, 403 is a reception radio unit, 404 is an in-phase component of a reception quadrature baseband signal, 405 is a quadrature component of the reception quadrature baseband signal, 406 is a frame / symbol timing detection unit, 407 is a frame / symbol timing signal, 408 is a frequency offset compensator which is a frequency offset compensator, 409 is a phase fluctuation amount correlation signal,
410 is an in-phase component of the interpolated known signal, 411 is a quadrature component of the interpolated known signal, 412 is a detection unit, and 413 is a digital signal.

FIG. 5 is a block diagram showing a specific configuration of the frequency offset compensator 408. In FIG.
501 is the in-phase component of the received quadrature baseband signal, 502
Is a quadrature component of the received quadrature baseband signal, 503 is a frame / symbol timing signal, 504 is a phase variation calculator, 505 is a phase variation signal between known symbols, 50
6 is a storage unit, 507 is a phase variation amount signal between immediately preceding known symbols, 508 is a frequency offset calculation unit, 509 is a phase variation amount correlation signal, 510 is an in-phase component of the interpolated known signal, and 511 is an interpolated known signal. This is the orthogonal component of the signal.

The operation of the demodulator and the frequency offset compensator according to the present embodiment will be described with reference to FIGS. Note that the configuration in FIG. 3 is the same as in (Embodiment 1), and a description thereof will be omitted.

In the demodulator shown in FIG.
In step 01, the reception signal 402 is received, and the reception radio section 403 inputs the reception signal 402, performs quadrature demodulation, and outputs the in-phase component 404 and the quadrature component 405 of the reception quadrature baseband signal.

Frame / symbol timing detector 40
6 receives the in-phase component 404 and the quadrature component 405 of the received quadrature baseband signal, synchronizes the frame and the symbol, and outputs the frame and symbol timing signal 407.

The frequency offset compensating section 408 includes an in-phase component 404 and a quadrature component 40 of the received quadrature baseband signal.
5. The frame / symbol timing signal 407 is input, the phase variation is calculated, correlation is performed, and the known signal is interpolated. The phase variation correlation signal 409 and the in-phase component 410 and the quadrature component 411 of the interpolated known signal are calculated. Output.

The detection section 412 includes an in-phase component 404 and a quadrature component 405 of the received quadrature baseband signal, a frame / symbol timing signal 407, and a phase variation correlation signal 40.
9. Inputting the interpolated known signal 410 and orthogonal component 411, detection is performed, and a digital signal 413 is output.

The frequency offset compensator 408 shown in FIG.
The configuration will be specifically described below. In the present embodiment, as shown in FIG. 3, the frame configuration in which one known symbol is inserted every eight symbols, and in particular, the frequency offset amount of 1 to 7 of the symbol of block j of data symbol 301 is used. An example of the estimation will be described. It is assumed that a single carrier system is used as a communication system.

The phase variation calculator 504 receives the in-phase component 501 and the quadrature component 502 of the received quadrature baseband signal and the frame / symbol timing signal 503, extracts a known symbol, and calculates the phase variation between the known symbols. , As a phase variation signal 505 between known symbols.

The storage unit 506 stores a phase variation amount signal 505 between known symbols and a frame / symbol timing signal 5.
03 and the phase fluctuation amount signal 50 at that timing.
5, and outputs a phase variation signal 507 between pilot symbols immediately before that has already been held.

The frequency offset calculator 508 includes a phase variation signal 505 between known symbols, a phase variation signal 507 between pilot symbols immediately before the phase variation signal 505 between known symbols, and an in-phase component of the received quadrature baseband signal. 501, the orthogonal component 502, and the frame / symbol timing signal 503 are input, the phase variation signal 505 is compared with the immediately preceding phase variation signal 507, and the correlation value and the like are interpolated as the phase variation correlation signal 509. The in-phase component 510 and the quadrature component 511 of the known signal are output.

The operation of the frequency offset calculator 508 is
The phase variation between the known symbols at i-2, i-1 and i of the known symbol 302 will be described as an example. The phase variation calculator 504 calculates the phase variation θ _i between the known symbols from the known symbols i−1 and i using (Equation 1),
The signal is output as a phase fluctuation amount signal 505 between known symbols.

Here, X _i−1 is the i of the known symbol 302
-1 is the in-phase component of the received signal, and Y _i-1 is the known symbol 30.
X _i is the in-phase component of the i received signal of the known symbol 302, and Y _i is the quadrature component of the i received signal of the known symbol 302.

The storage unit 506 stores the known symbols i-1, i
Held by entering the phase deviation theta _i between known symbols obtained from, already held, the phase between the known symbols determined from known symbol i-2, i-1 obtained by (Equation 2) The variation θ _i−1 is output as the phase variation signal 507 between the immediately preceding known symbols.

Where X _i−2 is _i of the known symbol 302
-2, the in-phase component of the received signal of Y _-2, the known symbol 30
2 i-2 is the orthogonal component of the received signal.

The frequency offset calculator 508 calculates the phase variation θ _i between the known symbols obtained from i−1, _{i of} the known symbol 302 and i−2, i−1 of the known symbol 302.
The phase variation θ _i−1 between known symbols obtained from the above is input, θ _i , θ _i−1 are compared, and for example, (Equation 3) is output as a phase variation correlation signal 209, and this signal is detected by a detector. 41
2 and a CPU unit (not shown) receive and use the data symbols for processing.

For example, when (Expression 4) is obtained,
By using θ _i and θ _i−1 in the calculation for estimating the frequency offset amount, the frequency offset amount is estimated with high accuracy.

[0054]

(Equation 4)

As a result, even when the reception electric field strength is weak or the fluctuation is severe, it is possible to obtain a good bit error rate characteristic with respect to the carrier power to noise power ratio.

As described above, by configuring the frequency offset compensating apparatus as shown in FIG. 5, it is possible to perform appropriate frequency offset compensation even when the received electric field strength is weak or the fluctuation is severe. In this case, good bit error rate characteristics can be obtained. By using such a frequency offset compensator as a frequency offset compensator as shown in FIG. 4, a demodulator having a good bit error rate characteristic can be obtained.

In this embodiment, the frame configuration has been described with reference to FIG. 3. However, the present invention is not limited to this, and the single carrier system has been described as a communication system. Has the same effect.

(Embodiment 3) FIG. 6 is a configuration block diagram showing an example of a demodulation device of a radio communication system according to the present embodiment. In FIG. 6, reference numeral 601 denotes an antenna;
02 is a reception signal, 603 is a reception radio unit, 604 is an in-phase component of a reception quadrature baseband signal, 605 is a quadrature component of the reception quadrature baseband signal, 606 is a frame / symbol timing detection unit, 607 is a frame / symbol timing signal, 608 is a frequency offset compensator which is a frequency offset compensator, 609 is a phase variation correlation signal,
610 is an in-phase component of the received quadrature baseband signal after frequency offset compensation, 611 is a quadrature component of the received quadrature baseband signal after frequency offset compensation, 612 is a detection unit, and 613 is a digital signal.

FIG. 7 is a block diagram showing a specific configuration of the frequency offset compensator 608. In FIG.
701 is an in-phase component of the received quadrature baseband signal;
Is a quadrature component of the received quadrature baseband signal, 703 is a frame / symbol timing signal, 704 is a phase variation calculator, 705 is a phase variation signal between known symbols, 70
6 is a storage unit, 707 is a phase variation signal between immediately preceding known symbols, 708 is a frequency offset calculator, 709 is a phase variation correlation signal, 710 is an in-phase component of a received quadrature baseband signal after frequency offset compensation, 711 Is the orthogonal component of the received orthogonal baseband signal after frequency offset compensation.

The operation of the demodulator and the frequency offset compensator according to the present embodiment will be described with reference to FIGS. 3, 6, and 7. Note that the configuration in FIG. 3 is the same as in (Embodiment 1), and a description thereof will be omitted.

In the demodulator shown in FIG.
01, the reception signal 602 is received, the reception radio section 603 receives the reception signal 602, performs quadrature demodulation, and outputs an in-phase component 604 and a quadrature component 605 of the reception quadrature baseband signal.

Frame / symbol timing detector 60
6 receives the in-phase component 604 and the quadrature component 605 of the received quadrature baseband signal, synchronizes the frame and the symbol, and outputs the frame and symbol timing signal 607.

The frequency offset compensator 608 includes the in-phase component 604 and the quadrature component 60 of the received orthogonal baseband signal.
5. The frame / symbol timing signal 607 is input, the phase shift amount is obtained, correlation is performed, and frequency offset compensation is performed. The phase shift amount correlation signal 609 and the in-phase component 610 of the received quadrature baseband signal after frequency offset compensation are used. The orthogonal component 611 is output.

Detection section 612 includes in-phase component 610 and quadrature component 611 of the received quadrature baseband signal after frequency offset compensation, frame / symbol timing signal 607,
A phase fluctuation amount correlation signal is input, detection is performed, and a digital signal 613 is output.

The frequency offset compensator 708 shown in FIG.
The configuration will be specifically described below. In the present embodiment, as shown in FIG. 3, the frame configuration in which one known symbol is inserted every eight symbols, and in particular, the frequency offset amount of 1 to 7 of the symbol of block j of data symbol 301 is used. An example of the estimation will be described. It is assumed that a single carrier system is used as a communication system.

The phase variation calculator 704 receives the in-phase component 701 and the quadrature component 702 of the received quadrature baseband signal and the frame / symbol timing signal 703, extracts known symbols, and obtains the phase variation between known symbols. , As a phase variation signal 705 between known symbols.

The storage unit 706 stores the phase variation amount signal 705 between the known symbols and the frame / symbol timing signal 5
03 and the phase fluctuation amount signal 70 at that timing.
5, and outputs the phase variation amount signal 707 between the pilot symbols immediately before that has already been stored.

The frequency offset calculator 708 includes a phase variation signal 705 between known symbols, a phase variation signal 707 between pilot symbols immediately before the phase variation signal 705 between known symbols, and an in-phase component of the received quadrature baseband signal. 701, an orthogonal component 702, and a frame / symbol timing signal 703 are input, a phase variation signal 705 is compared with the immediately preceding phase variation signal 707, and a correlation value or the like is obtained as a phase variation correlation signal 709. In-phase component 710 of subsequent received quadrature baseband signal
And the orthogonal component 711.

The operation of the frequency offset calculator 508 is
The phase variation between the known symbols at i-2, i-1 and i of the known symbol 302 will be described as an example. The phase variation calculator 704 obtains the phase variation θ _i between the known symbols from the known symbols i−1 and i using (Equation 1),
This is output as a phase variation signal 705 between known symbols.

Here, X _i-1 is the i of the known symbol 302
-1 is the in-phase component of the received signal, and Y _i-1 is the known symbol 30
X _i is the in-phase component of the i received signal of the known symbol 302, and Y _i is the quadrature component of the i received signal of the known symbol 302.

The storage unit 706 stores the known symbols i−1, i
Held by entering the phase deviation theta _i between known symbols obtained from, already held, the phase between the known symbols determined from known symbol i-2, i-1 obtained by (Equation 2) The variation θ _i−1 is output as the phase variation signal 707 between the immediately preceding known symbols.

Here, X _i−2 is _i of known symbol 302
-2, the in-phase component of the received signal of Y _-2, the known symbol 30
2 i-2 is the orthogonal component of the received signal.

The frequency offset calculator 708 calculates the phase variation θ _i between the known symbols obtained from i−1, _{i of} the known symbol 302 and i−2, i−1 of the known symbol 302.
The phase variation θ _i−1 between known symbols obtained from the above is input, θ _i , θ _i−1 are compared, and for example, (Equation 3) is output as a phase variation correlation signal 209, and this signal is detected by a detector. 61
2 and a CPU unit (not shown) receive and use the data symbols for processing.

For example, when (Expression 4) is obtained,
By using θ _i and θ _i−1 in the calculation for estimating the frequency offset amount, the frequency offset amount is estimated with high accuracy.

As a result, even when the received electric field strength is weak or the fluctuation is severe, it is possible to obtain a good bit error rate characteristic with respect to the carrier power to noise power ratio.

As described above, by configuring the frequency offset compensating apparatus as shown in FIG. 7, it is possible to perform appropriate frequency offset compensation even when the received electric field strength is weak or the fluctuation is severe. In this case, good bit error rate characteristics can be obtained. By using such a frequency offset compensator as a frequency offset compensator as shown in FIG. 6, a demodulator having a good bit error rate characteristic can be obtained.

In this embodiment, the frame configuration has been described with reference to FIG. 3. However, the present invention is not limited to this. In addition, although a single carrier system has been described as a communication system, a code division multiple system may be used. Has the same effect.

[0078]

As described above, according to the present invention, a receiving quadrature baseband is used for a radio communication demodulator in which a transmitting side inserts a known signal into transmission data and transmits the data, and a receiving side receives and demodulates. Phase fluctuation calculating means for inputting an in-phase component and a quadrature component of a signal and a timing signal, and outputting a phase fluctuation signal between known symbols at a certain timing; and Storage means for holding a quantity signal and outputting a past phase variation signal between known symbols input and retained at a timing earlier than the certain timing as a past phase variation signal; and the phase variation signal And a correlation detecting means for inputting the past phase variation signal and the timing signal and outputting a phase variation correlation signal, or the phase variation signal and the The in-phase component and the quadrature component of the received quadrature variation signal and the received quadrature baseband signal and the timing signal are input to interpolate the in-phase component and the quadrature component of the known signal, and the phase variation correlation signal and the in-phase of the interpolated known signal are input. Frequency offset calculating means for outputting a component and a quadrature component, or frequency offset compensation by inputting the phase variation signal, the past phase variation signal, and the in-phase component and the quadrature component of the received quadrature baseband signal and the timing signal. And a frequency offset calculating means for outputting an in-phase component and a quadrature component of the phase variation correlation signal and the received quadrature baseband signal after the frequency offset compensation. The demodulator can be used when the received electric field strength is weak or It can have the advantageous effect of obtaining a good bit error rate characteristic can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram illustrating an example of a demodulation device of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of a control device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of a frame configuration of a data symbol and a known symbol with respect to time according to an embodiment of the present invention.

FIG. 4 is a configuration block diagram illustrating an example of a demodulation device of a wireless communication system according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a specific configuration of a frequency offset compensator according to one embodiment of the present invention;

FIG. 6 is a configuration block diagram illustrating an example of a demodulation device of a wireless communication system according to an embodiment of the present invention.

FIG. 7 is a block diagram showing a specific configuration of a frequency offset compensator according to one embodiment of the present invention;

FIG. 8 is a conceptual diagram showing a temporal change in the phase of a pilot symbol by conventional frequency offset compensation.

[Explanation of symbols]

101, 401, 601 Antenna 102, 402, 602 Received signal 103, 403, 603 Received radio section 104, 201, 404, 501, 604, 701 In-phase component of received quadrature baseband signal 105, 202, 405, 502, 605, 702 Orthogonal component of received orthogonal baseband signal 106, 406, 606 Frame / symbol timing detector 107, 203, 407, 503, 607, 703 Frame / symbol timing signal 108 Controller 109 Phase variation correlation signal 110, 412, 612 Detector 111, 413, 613 Digital signal 204, 504, 704 Phase variation calculator 205, 505, 705 Phase variation signal between known symbols 206, 506, 706 Storage 207, 507, 707 Between known symbols immediately before Phase variation signal 208 Correlation detector 209, 409, 509, 609, 709 Phase variation correlation signal 301 Data symbol 302 Known symbol 408, 608 Frequency offset compensator 410, 510 In-phase component of interpolated known signal 411, 511 interpolation 508, 708 Frequency offset calculator 610, 710 In-phase component of received quadrature baseband signal after frequency offset compensation 611, 711 Quadrature component of received quadrature baseband signal after frequency offset compensation

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Masayuki Orihashi 3-10-1, Higashi-Mita, Tama-ku, Kawasaki, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Akihiko Matsuoka 3-chome, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa No.10 No.1 Matsushita Giken Co., Ltd. F-term (reference) 5K004 AA08 JJ05 JJ08 5K052 AA14 CC06 DD03 DD04 EE17 EE26 EE30 EE38 FF31 GG11

Claims (6)

[Claims] A transmission side inserts a known signal into transmission data, transmits the transmission signal, and uses the reception side to receive and demodulate the data. The in-phase component and the quadrature component of a received quadrature baseband signal and a timing signal are used. And a phase fluctuation amount calculating means for outputting a phase fluctuation amount signal between known symbols at a certain timing, and holding the phase fluctuation amount signal with the phase fluctuation amount signal and the timing signal as inputs, and Storage means for outputting as a past phase variation signal a phase variation signal between known symbols that has been input and held at a past timing; and inputs the phase variation signal, the past phase variation signal and a timing signal. And a correlation detecting means for outputting a phase fluctuation amount correlation signal. 2. A demodulator for wireless communication in which a transmitting side inserts a known signal into transmission data and transmits the data, and a receiving side demodulates and receives the signal. The in-phase component and the quadrature component of the received quadrature baseband signal and the timing signal are used. And a phase fluctuation amount calculating means for outputting a phase fluctuation amount signal between known symbols at a certain timing, and holding the phase fluctuation amount signal with the phase fluctuation amount signal and the timing signal as inputs, and Storage means for outputting a past phase variation signal between known symbols input and held at a past timing as a past phase variation signal; and the phase variation signal, the past phase variation signal, and the reception quadrature base. The in-phase and quadrature components of the band signal and the timing signal are input, and the in-phase and quadrature components of the known signal are interpolated. A frequency offset compensating unit that outputs an in-phase component and a quadrature component of the obtained known signal. 3. A radio communication demodulator for transmitting a known signal by inserting a known signal into transmission data on a transmission side and receiving and demodulating on a reception side, wherein the in-phase component and the quadrature component of a reception quadrature baseband signal and a timing signal are used. And a phase fluctuation amount calculating means for outputting a phase fluctuation amount signal between known symbols at a certain timing, and holding the phase fluctuation amount signal with the phase fluctuation amount signal and the timing signal as inputs, and Storage means for outputting a past phase variation signal between known symbols input and held at a past timing as a past phase variation signal; and the phase variation signal, the past phase variation signal, and the reception quadrature base. Inputs the in-phase and quadrature components of the band signal and the timing signal, performs frequency offset compensation, and outputs the phase variation correlation signal and frequency off signal. A frequency offset compensator comprising: a frequency offset calculator that outputs an in-phase component and a quadrature component of a received quadrature baseband signal after set compensation. 4. A demodulation device comprising the device according to claim 1. 5. The demodulator according to claim 4, wherein the wireless communication is of a single carrier type. 6. The demodulation device according to claim 4, wherein the wireless communication is a code division multiplex system.