JPH0821887B2 - Data receiving device - 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. 2 is a block diagram showing a schematic configuration of a conventional data receiving device. In FIG. 2, 121 is a received signal, and 122 is an impulse which inputs the received signal 121, estimates the complex impulse response of the line from known signals included in the received signal 121, and outputs a complex impulse response. It is a response estimator.

Reference numeral 123 is an equalizer that equalizes the received signal 121 based on the output of the impulse response estimator 122 and outputs a demodulated signal 124.

Next, the operation of the above conventional example will be described. In FIG. 2, an impulse response estimator 122 estimates the complex impulse response of the line from a known signal or the like contained in the received signal 121 and gives the information to the equalizer 123.

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

Thus, even in the conventional data receiving device, it is possible to estimate the complex impulse response of the line by the impulse response estimator 122, it is possible to use the information,
When the complex impulse response of the line does not fluctuate with time, deterioration due to frequency selective fading or the like can be removed, and a demodulated signal with a good error rate can be obtained.

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, the complex impulse response estimated first is used for the received signal at a time different from the time when the complex impulse response is estimated. Therefore, there is a problem that the effect of equalization deteriorates when the complex impulse response of the line fluctuates with time.

The present invention is to solve such a conventional problem, and to provide an excellent data receiving apparatus capable of preventing the equalization effect from deteriorating even if the complex impulse response of the line fluctuates with time. It is intended.

Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of impulse response estimators for estimating a complex impulse response of a line at different times by inputting a received signal, and an estimation by the impulse response estimator. A coefficient setter for setting a coefficient for modeling the generated complex impulse response, a delayer for storing only an initial value of the complex impulse response by the first estimation of the impulse response estimator, and a second of the impulse response estimator.
The value of the complex impulse response estimated from the second time onward and the model coefficient output from the coefficient setting device are input, and a multiplier that multiplies each of them and an adder that adds the multiplication result of this multiplier and outputs to the delay device And an arithmetic unit configured to include the delay unit, the multiplier, and the adder, which outputs an estimated value, an estimated value output from the arithmetic unit, which equalizes a received signal and outputs a demodulated signal. And a chemical converter.

Operation According to the present invention, therefore, the complex impulse responses of the lines at different times are estimated by the plurality of impulse response estimators, and the coefficient setting calculator sets the coefficient for modeling the complex impulse response and performs the calculation. In the means, the coefficient set by the coefficient setter is multiplied by each complex impulse response, and each multiplication result is added,
By passing the result of this addition through a delay device and outputting the estimated value, it is possible to approximate the complex impulse response at different points in time with a constant model formula, and to sequentially estimate the complex impulse response at any point in the line. Even if there is a temporal change in the complex impulse response of the line, 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 Figure 1, 1 is the received signal, 2 ₀ to 2 _M-1, the received signal respectively 1
Is an impulse response estimator that estimates a complex impulse response of a line at different points in time using a known signal included in the received signal 1 and outputs complex impulse responses 3 _{0 to} 3 _M-1 ( M is the number of impulse response estimators).

4 inputs the initial value of the complex impulse response 3 ₀ ~3 _M-1 output from each of the impulse response estimator 2 ₀ ~2 _M-1, each complex impulse response 3 ₀ ~3 _M-1 It is a coefficient setter that outputs AR model coefficients 8 ₀ to 8 _M-1 which are coefficients for modeling.

The AR model coefficients referred to here, the impulse response 3 _0-3
It is a coefficient used when modeling and approximating a probabilistic time series such as _M-1 . For example, the probabilistic time series y (t) is model y (t) = − a ₁ y (t−1) −a ₂ y (t-2) ...- a _n y
In the case of generating by (t−n) + b ₀ v (t), a ₁ , a ₂ , ..., A _n in the above equation
Refers to.

5 _{0 to} 5 _M-1 are the delay response 6 _{1 to} 6 _M-1 side depending on the initial value of the impulse response 3 _{0 to} 3 _M-1 output from the impulse response estimator 2 ₀ to 2 _M-1 . From terminals A _{0 to} A _M-1 Multiplier 7 _{0 to} 7 _M-1
It is a selector switch that switches to the side terminals B _{0 to} B _M-1 .

The delay devices 6 _{1 to} 6 _M-1 are impulse response estimators 2 ₀ to 2
Being adapted to store only the initial value of the complex impulse response 3 ₀ ~3 _M-1 by the first estimate of the _M-1, complex impulse by the second and subsequent estimation of the impulse response estimator 2 ₀ to 2 _M-1 response 3 ₀ to 3 _M-1, the changeover switch 5 ₀ in accordance with the response
By 5 _M-1 is switched to the multiplier 7 ₀ ~7 _M-1 side of the terminal B ₀ ~B _M-1, are input to the multiplier 7 ₀ ~7 _M-1.

Further, the multiplier 7 ₀ to _7-M-1, the impulse response estimator 2 ₀ to 2 _M-1 in estimated secondly or later the complex impulse response 3 ₀ to 3 _M-1 is the change-over switch 5 ₀ - The AR set by the coefficient setter 4 while being input through 5 _M-1
Model Number 8 ₀ ~8 _M-1 also are input together.

As a result, the multipliers 7 _{0 to} 7 _M-1 have AR model coefficients 8 ₀ to 8 _M-1.
When complex impulse response 3 estimated secondly or later ₀ to 3 _M-1
It is designed to perform multiplication with.

An adder 9 adds the multiplication results output from the multipliers 7 _{0 to} 7 _M-1 and outputs the addition result to the delay units 6 _{1 to} 6 _M-1 via the changeover switch 5 _M-1 . , 13 are the changeover switches
Comprising 5 _{0 to} 5 _M-1 , delay units 6 _{1 to} 6 _M-1 , multipliers 7 _{0 to} 7 _M-1 and adder 9, it is an arithmetic means for calculating an estimated value 10.

11, the delay unit 6 ₁ ~6 _M-1 through the change-over switch 5 _M-1
It is an equalizer that inputs an estimated value 10 based on the addition result input to and outputs the demodulated signal 12 by equalizing the received signal.

Next, the operation of the above embodiment will be described. In the above embodiment, the impulse response estimator 2 ₀ to 2 _M-1 using a known signal or the like included in the received signal 1, to estimate the complex impulse response of the channel at different times, they complex impulse response h (0 ; n), h (1; n), ..., h (M-1; n)
(N is the impulse response number).

Here, assuming that the time variation of the complex impulse response h (t, n) can be approximated by the AR model, [X is the order of the AR model, and a (i, n) is the coefficient of the AR model].

Therefore, the order X of the AR model is determined, and the coefficient a of the AR model is determined.
If (i, n) is obtained, the complex impulse response h (t, n) at any time can be estimated. In this embodiment, a plurality of complex impulse response h by a plurality of impulse response estimator _{2 0 ~2 M-1 (0} , n), h (1, n), ..., h (M
−1, n), the order X of the AR model is maximum M−1.
Becomes

From the above equation (I), the coefficient a (i, n) of the AR model that minimizes the squared error between both sides is t = M−1, X = M−1.
In order to obtain at the time of, first, h on both sides of the equation (I)
^* If you take the expected value by multiplying (M-1-j, n), Becomes Here, the complex impulse response h (0, n), h (1,
Complex impulse responses other than n), ..., H (M−1, n) are set to 0. Also, K = 1 to (M-1). If this is expressed in a matrix, Becomes

By solving this determinant, the coefficient a (i,
n) is obtained.

The coefficient calculator 4 performs this calculation and calculates the coefficient a of the AR model.
(0, n) and outputs ~a the (M-1, n) as an AR model coefficients 8 ₀ ~8 _M-1.

On the other hand, the initial value of the complex impulse response 3 _{0 to} 3 _M-1 output from the impulse response estimator 2 ₀ to 2 _M-1 is the changeover switch.
Stored in the delay line by delays 6 _{1 to} 6 _M-1 only at the very first estimation of the complex impulse response by 5 _{0 to} 5 _M-1 .

When estimating the complex impulse response from the second time onwards,
Selector switches 5 _{0 to} 5 _M-1 are delay devices 6 _{1 to} 6 _M-1 side terminals A _{0 to} A
_{From M-1} to the multipliers 7 _{0 to} 7 _M-1 side terminals B _{0 to} B _M-1 , the newly estimated complex impulse response is input to the multipliers 7 _{0 to} 7 _M-1. .

In the complex impulse response input to the multipliers 7 _{0 to} 7 _M-1 , here, the AR model coefficient obtained by the coefficient setter 4 is used.
8 ₀ to 8 _M-1 are multiplied, and the multiplication results of the respective multipliers 7 _{0 to} 7 _M-1 are added by the adder 9. This operation realizes the formula (I).

The impulse response thus obtained is input to the equalizer 11 as an estimated value 10 via the changeover switch 5 _M-1 and the delay devices 6 _{1 to} 6 _M-1 . The equalizer 11 equalizes the received signal 1 using the information of the estimated value 10 to obtain a demodulated signal 12.

As described above, according to the above-described embodiment, the time variation of the complex impulse response of the line is predicted, and the complex impulse response at any time can be estimated by the AR model coefficients 8 ₀ to 8 _M-1. Equalizer 11 can be used to equalize received signal 1 using 10, and even if the complex impulse response of the line fluctuates with time, deterioration of equalization performance can be suppressed and error rate can be reduced. This has the advantage that the demodulated signal 12 with good characteristics can be obtained.

The above example was estimated complex impulse response as an impulse response estimator 2 ₀ ~2 _M-1, but the complex impulse response, h (t; n) = hi (t; n) + jh q (t; n), and the real part hi (t; n) and the imaginary part h _q (t; n) may be separately estimated. In this case, the configuration and operation are the same as in the above embodiment.

Also, the complex impulse response is considered as h (t; n) = γ (t; n) × e ^{jθ (t; n)} and divided into an amplitude component γ (t; n) and a phase component θ (t; n). , May be estimated independently. In this case as well, the configuration and operation are the same as in the above embodiment.

EFFECTS OF THE INVENTION As described above, according to the present invention, a plurality of impulse response estimators for inputting a received signal to estimate complex impulse responses of lines at different times, and a complex impulse response estimated by the impulse response estimator are provided. A coefficient setter for setting a coefficient for modeling, a delayer for storing only an initial value of a complex impulse response by the first estimation of the impulse response estimator, and a complex by the second and subsequent estimations of the impulse response estimator. The value of the impulse response and the model coefficient output by the coefficient setting device are input, a multiplier for multiplying each of them, an adder for adding the multiplication results of this multiplier and outputting to the delay device, the delay device, Computation means including the multiplier and the adder, which outputs an estimated value, and an estimated value output by the arithmetic means are input to equalize and demodulate a received signal. An equalizer for outputting a signal is provided.

Therefore, the multiple impulse response estimators estimate the complex impulse responses of the lines at different times, and the coefficient setter sets the coefficient for modeling this complex impulse response. Multiply the coefficient set by and the individual complex impulse response,
Furthermore, by adding each multiplication result and passing the addition result through a delay device to output an estimated value, the complex impulse response at different time points is approximated by a certain model formula, and the complex impulse response at any time point on the line is approximated. Since the impulse responses can be sequentially estimated, the equalization can be performed without deterioration of the effect even if the complex impulse response of the line changes with time.

[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 FIG. 2 is a block diagram showing a schematic configuration of a conventional data receiving apparatus. 2 ₀ ~2 _M-1 ...... impulse response estimator, 4 ...... coefficient setter, 6 ₁ ~6 _M-1 ...... _{delayer, 8 0 ~8 M-1 ......} AR model coefficients,
11 …… equalizer, 13 …… computing means.

Claims (1)

[Claims] 1. A plurality of impulse response estimators for inputting a received signal and estimating complex impulse responses of lines at different times, and coefficients for modeling the complex impulse responses estimated by the impulse response estimators. A coefficient setting device for setting, a delay device for storing only an initial value of the complex impulse response by the first estimation of the impulse response estimator, a value of the complex impulse response by the second and subsequent estimations of the impulse response estimator and the coefficient A multiplier for inputting the model coefficients output from the setter, for multiplying each of them, an adder for adding the multiplication results of this multiplier and outputting it to the delay device, the delay device, the multiplier, and the adder And an equalizer for outputting the estimated value and an equalizer for inputting the estimated value output by the arithmetic means to equalize the received signal and output the demodulated signal. For example was the data receiving device.