JPH07105752B2 - Data receiver - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data receiving device used for digital mobile communication and the like.

2. Description of the Related Art Digital data communication devices are widely used in recent years because they can perform so-called signal equalization, which compensates for signal waveform distortion on the receiving side, and thus high fidelity is obtained. It has become.

A conventional data receiving apparatus of this type will be described below with reference to 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 of a line including a plurality of complex impulses at different time points, and 122 is an input of the received signal 121, and a complex impulse response of the line is estimated from a known signal included in the received signal 121. The impulse response estimator 123 is an equalizer that receives the output of the impulse response estimator 122, equalizes the received signal 121, and outputs a demodulated signal 124.

Next, the operation of the above conventional example will be described. In FIG. 3, impulse response estimator 122 estimates the complex impulse response of the line from the known signal included in received signal 121 and gives the information to equalizer 123.

The equalizer 123 equalizes the received signal 121 based on this information, so that the demodulated signal 124 having a low error rate by removing the deterioration due to frequency selective fading or the like is removed as compared with the case where the received signal 121 is demodulated as it is. Can be obtained.

As described above, even in the above conventional data receiving apparatus, the complex impulse response of the line can be estimated by the impulse response estimator 122 and the information can be used, so that there is no time variation in the complex impulse response of the line. Has
It is possible to remove deterioration due to frequency selective fading and the like, and it is possible to obtain a demodulated signal 124 with a good error rate.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above conventional data receiving apparatus, once the complex impulse response is estimated, even for a received signal at a time different from the time when the complex impulse response is estimated,
Since the complex impulse response estimated first is used for equalization, there is a problem that the effect of equalization deteriorates when the complex impulse response of the line fluctuates.

The present invention solves such conventional problems,
An object of the present invention is to provide an excellent data receiving apparatus which can prevent the equalization effect from deteriorating even if the complex impulse response of the line fluctuates with time.

Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of impulse response estimators for estimating complex impulse responses of a line at different times from a received signal, and outputs from each of the impulse response estimators. A coefficient calculator that inputs a complex impulse response to obtain a sine wave coefficient, and a plurality of sine wave generators that generate approximate sine waves of different complex impulse responses at different times according to the sine wave coefficient. An adder that adds the outputs of a plurality of sine wave generators and outputs an estimated value of the time variation of the complex impulse response at different times, and the received signal is equalized by the estimated value to obtain a demodulated signal. An equalizer for outputting is provided.

Action According to the present invention, therefore, the complex impulse response of the line at different time points is estimated by a plurality of impulse response estimators, and this is approximated by a plurality of sine wave models, and the time of the complex impulse response at any time point of the line is calculated. By estimating the dynamic fluctuation, even if the complex impulse response of the line fluctuates with time, equalization can be performed without deterioration of the effect.

Embodiment An embodiment of the present invention will be described below with reference to 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, reference numeral 1 is a received signal, and 20 to 20+ (M-1) are the complex impulse responses 30 to 30+ ( M-
1) is an impulse response estimator (M is the number of impulse response estimators).

4 inputs the complex impulse response 30-30 + (M-1) output from the impulse response estimator 20-20 + (M-1), and each of the sine wave generators 60-60 + (N-1) It is a coefficient calculator that obtains a coefficient and outputs a sine wave coefficient of 50 to 50+ (N-1) (N is the number of sine wave generators).

The sine wave generator 60-60 + (N-1) is a coefficient generator 4
Each of the sine wave coefficients 50 to 50+ (N-1) output from is input, and the temporal variation of the complex impulse response at an arbitrary time point is estimated and output.

An adder 7 inputs the outputs of the sine wave generators 60 to 60+ (N-1), adds the outputs, and outputs the estimated value 8 to the equalizer 9. The equalizer 9 demodulates the received signal 1 based on the estimated value 8 and outputs a demodulated signal 10.

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

In the above embodiment, the impulse response estimators 20 to 20+ (M-1) are used to estimate the complex impulse response of the line at the time of deviation using the known signal included in the received signal 1 and 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 an arbitrary positive number). FIG. 2 (a) is an average spectrum when a long-time spectral response h (t, x) is observed, and f _{D in} the figure shows the maximum Doppler frequency.

However, since the processing is actually performed within a limited time range, it is considered that the processing is as shown in FIG. 2 (b) or FIG. 2 (c) within that range (the frequency at which the spectrum stands is the arrival direction of the elementary wave). Depends on).

Therefore, considering approximating the complex impulse response with multiple sine waves, And

In this formula (I), N is a coefficient of a sine wave. Since there are three types of sine wave coefficients: amplitude a, frequency ω, and phase θ, assuming N waves, it is necessary to obtain 3N coefficients. This coefficient is the complex impulse response h (0, n)
.About.h (M-1, n), that is, 30 to 30+ (M-1), is calculated by the least squares method in the coefficient calculator 4.

In general, the number 3N of solutions is limited by the number M of complex impulse responses such that 2 (M−1) ≧ 3N. In this way
Sine wave coefficient 50 to 50+ calculated by coefficient calculator 4
With (N-1), the sine wave generators 60 to 60+ (N-1) generate elementary waves that satisfy the equation (I), and the adder 7 adds them to obtain an estimated value 8.

By outputting this estimated value 8 to the equalizer 9, the equalizer 9 uses this information to equalize the received signal 1 and the demodulated signal 10
Is output.

As described above, according to the above embodiment, the estimated value 8 of the complex impulse response can be obtained at any time,
By using this to perform equalization on the received signal 1 by the equalizer 9, it is possible to obtain a demodulated signal with a good error rate characteristic even when there is a temporal change in the complex impulse response of the line. Have.

EFFECTS OF THE INVENTION As described above, according to the present invention, a plurality of impulse response estimators for estimating complex impulse responses of a line at different time points from a received signal and a complex impulse response output from each of the impulse response estimators are calculated. A coefficient calculator that inputs the sine wave coefficients, a plurality of sine wave generators that generate approximate sine waves of different complex impulse responses at different times by the sine wave coefficients, and a plurality of sine wave generators An adder that outputs the estimated values of the temporal fluctuations of the complex impulse responses at different time points, and an equalizer that outputs the demodulated signal by equalizing the received signal with the estimated value. It is configured to include.

Therefore, the multiple impulse response estimators estimate the complex impulse response of the line at any point in time, and approximate this with multiple sine wave models, and estimate the temporal fluctuation of the complex impulse response at any point in the line. With
The estimated value can be used to equalize the received signal,
Even if the complex impulse response of the line fluctuates with time, equalization can be performed without deterioration of the effect, and good error rate characteristics can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data receiving apparatus according to an embodiment of the present invention, and FIGS. 2 (a) to 2 (c).
FIG. 3 is an explanatory diagram showing a 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. 20 to 20+ (M-1) ... Impulse response estimator, 4 ...
Coefficient calculator, 60-60 + (N-1) ... Sine wave generator, 7
…… Adder, 9 …… Equalizer.

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Claims (1)

[Claims] 1. A plurality of impulse response estimators for estimating complex impulse responses of a line at different times from a received signal, and complex impulse responses output from each of the impulse response estimators are input to obtain sine wave coefficients. A coefficient calculator for obtaining, a plurality of sine wave generators that generate approximate sine waves of different complex impulse responses at the above-mentioned time points according to the sine wave coefficients, and add the outputs of the plurality of sine wave generators. A data receiving apparatus comprising: an adder that outputs an estimated value of a temporal fluctuation of a complex impulse response at different time points; and an equalizer that equalizes the received signal based on the estimated value and outputs a demodulated signal.