JPH03278719A - Data receiver - Google Patents

Abstract

PURPOSE:To attain equalization without deterioration in the effect even when a complex number impulse response of one line is fluctuated with time by estimating the fluctuation with time of the complex number impulse response at an optional point of time of the line. CONSTITUTION:Sinusoidal wave generators 60-6(N-1) generate prescribed raw waves by using sinusoidal wave coefficients 50-5(N-1) obtained by a coefficient calculator 4 and added by an adder 7 to obtain an estimate value 8. The estimate value 8 is outputted to an equalizer 9 and the equalizer 9 uses the information to equalize a reception signal 1 and a demodulation signal 10 is outputted. Since the estimate value of the complex number impulse response is obtained at an optional point of time, the reception signal 1 is equalized at the equalizer 9 by using it. Thus, even when the complex number impulse response of the line is fluctuated with time, the effect of equalization is not deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a data receiving device used in digital mobile communications and the like.

Conventional technologyDigital data communication devices have been widely used in recent years because they can perform so-called signal equalization, which compensates for signal waveform distortion on the receiving side, thereby achieving high fidelity. It looks like this.

Hereinafter, a conventional data receiving device of this type will be explained based on the drawings.

FIG. 3 is a block diagram showing a schematic configuration of a conventional data receiving device. In FIG. 3, 121 is a received signal on a line containing a plurality of complex impulses at different times;
2 is an impulse response estimator that inputs this received signal 121 and estimates the complex impulse response of the line from known signals included in the received signal 121; 123 inputs the output of the impulse response estimator 122 and estimates the complex impulse response of the line from known signals included in the received signal 121 This is an equalizer that equalizes and outputs a demodulated signal 124.

Next, the operation of the above conventional example will be explained. In FIG. 3, the impulse response estimator 122 includes a received signal 121
The complex impulse response of the line is estimated from the known signals included in the circuit, and the information is provided to the isoflower 123.

By equalizing the received signal 121 based on this information, the equalizer 123 can remove deterioration caused by frequency selective fading and the like and generate a demodulated signal 124 with a lower error rate than when the received signal 121 is demodulated as is. Obtainable.

In this way, even in the conventional data receiving apparatus described above, the complex impulse response of the line can be estimated by the impulse response estimator 122, and that information can be used.
When there is no temporal variation in the complex impulse response of the line, deterioration due to frequency selective fading and the like can be removed, and a demodulated signal 124 with a good error rate can be obtained.

Problems to be Solved by the Invention However, once a complex impulse response is estimated in the above conventional data receiving device, even for a received signal at a time different from the time when the complex impulse response was estimated,
Since equalization is performed using the initially estimated complex impulse response, there is a problem in that the effect of equalization deteriorates when the complex impulse response of the line fluctuates.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent data receiving device that can prevent the equalization effect from deteriorating even if the complex impulse response of a line fluctuates over time.

Means for Solving the Problems In order to achieve the above object, the present invention includes a plurality of impulse response estimators that estimate complex impulse responses of lines at different times from received signals, and an output from each of the impulse response estimators. a coefficient calculator that calculates sine wave coefficients by inputting the complex impulse responses to be input; a plurality of sine wave generators that generate approximate sine waves of the complex impulse responses at different points in time using the sine wave coefficients; an adder that adds the outputs of a plurality of sine wave generators and outputs an estimated value of the temporal fluctuation of the complex impulse response at different points in time; and an adder that equalizes the received signal using the estimated value to generate a demodulated signal. The configuration includes a flower vase for output.

Therefore, according to the present invention, the complex impulse response of the line at different points in time is estimated by a plurality of impulse response estimators, approximated by a plurality of sine wave models, and the time of the complex impulse response at any point in the line is estimated. By estimating the physical fluctuations, equalization can be performed without deteriorating the effect even if the complex impulse response of the line fluctuates over time.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a data receiving apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a received signal, and 20 to 2 (M-1) are complex impulse responses 30 to 3 ( M-
1) (M is the number of impulse response estimators).

4 inputs the complex impulse responses 30 to 3 (M-1) output from the impulse response estimators 20 to 2 (M-1), and calculates each of the sine wave generators 60 to 6 (N-1). This is a coefficient/number calculator that calculates coefficients and outputs sine wave coefficients 50 to 5 (N-1) (N is the number of sine wave generators).

The sine wave generators 60 to 6 (N-1) are the coefficient generator 4
It inputs the sine wave coefficients 50 to 5 (N-1) outputted from each of the sine wave coefficients 50 to 5 (N-1), and estimates and outputs the temporal fluctuation of the complex impulse response at an arbitrary point in time.

7 is an adder that inputs and adds the outputs of the sine wave generators 60 to 6 (N-1), and outputs an estimated value 8 to the equalizer 9. Further, the flower vase 9 demodulates the received signal 1 based on this estimated value 8 and outputs a demodulated signal 10.

Next, the operation of the above embodiment will be explained.

In the above embodiment, the impulse response estimators 20 to 2 (M-1) use known signals included in the received signal 1 to estimate the complex impulse response of the line at the shifted time point, and calculate the complex impulse response h (0, n), h(
1, n), -h(M-1, n) (n is the impulse response number).

Now consider the spectrum of the complex impulse response. FIG. 2 shows the frequency spectrum of the complex impulse response h(t, x) (X is any positive number). Figure 2 (
a) is the average spectrum when observing the long-term spectral response h(t, x), and FD in the figure indicates the maximum Doppler frequency.

However, in reality, processing is performed within a limited time range, so within that range it is thought that the results will be as shown in Figure 2 (b) and Figure 2 (c) (the frequency at which the spectrum stands is in the direction of arrival of the elementary wave). ).

Therefore, we consider approximating the complex impulse response with multiple sine waves, and set it as (I).

In this equation (I), N is a coefficient of the sine wave. There are three types of sine wave coefficients: amplitude, frequency ω, and phase θ, so assuming N waves, it is necessary to find 3N coefficients. This coefficient is the complex impulse response h(0,
n) to h(M-1°0), that is, 30 to 3(M-1), is calculated using the coefficient calculator 4 by the least 'squares method.

In general, the number of solutions 3N is limited by the number M of complex impulse responses as 2(M-1)≧3N.

In this way, by using the sine wave coefficients 50 to 5 (N-1) obtained by the coefficient calculator 4, the sine wave generators 60 to
6(N-1) generates elementary waves that satisfy formula (I),
An estimate iI8 is obtained by adding them together in an adder 7.

By outputting this estimated value 8 to the equalizer 9, the equalizer 9 uses this information to equalize the received signal l, and demodulated signal 1
Outputs 0.

As described above, according to the above embodiment, it is possible to obtain the estimated value 8 of the complex impulse response at any time, so that
By using this to equalize the received signal 1 with the equalizer 9, it is possible to obtain a demodulated signal with good error rate characteristics even when the complex impulse response of the line fluctuates over time. has.

Effects of the Invention As described above, the present invention includes a plurality of impulse response estimators that estimate complex impulse responses of lines at different times from received signals, and a complex impulse response output from each of the impulse response estimators. a coefficient calculator that receives input and calculates sine wave coefficients; a plurality of sine wave generators that generate approximate sine waves of complex impulse responses at different points in time using the sine wave coefficients; an adder that adds the outputs of the receivers and outputs an estimated value of the temporal fluctuation of the complex impulse response at different points in time; and an equalizer that equalizes the received signal using the estimated value and outputs a demodulated signal. The configuration includes:

Therefore, multiple impulse response estimators are used to estimate the complex impulse response of the line at any point in time, approximate this using multiple sine wave models, and estimate the temporal variation of the complex impulse response at any point in the line. With,
The received signal can be equalized using the estimated value,
Even if the complex impulse response of the line fluctuates over time, equalization can be performed without deterioration of effectiveness, and good error rate characteristics can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a data receiving device according to an embodiment of the present invention, and FIGS. 2(a) to 2(C)
1 is an explanatory diagram showing the form of a frequency spectrum of a complex impulse response in the data receiving device of FIG. 1, and FIG. 3 is a block diagram showing a schematic configuration of a conventional data receiving device. 2o~2(M-1)... Impulse response estimator, 4.
... Coefficient calculator, 60 to 6 (N-1)... Sine wave generator, 7... Adder, 9... Equalizer.

Claims (1)

[Claims] A plurality of impulse response estimators that estimate the complex impulse responses of lines at different times from received signals, and a coefficient calculator that calculates sine wave coefficients by inputting the complex impulse responses output from each of the impulse response estimators. and a plurality of sine wave generators that generate approximate sine waves of complex impulse responses at different points in time using the sine wave coefficients, and complex impulse responses at different points in time by adding the outputs of the plurality of sine wave generators. A data receiving device comprising: an adder that outputs an estimated value of temporal fluctuation of an impulse response; and an equalizer that equalizes the received signal using the estimated value and outputs a demodulated signal.