JPH0630057A - Data receiver - Google Patents

Abstract

PURPOSE:To reduce mean computing quantity as keeping performance and to attain low power consumption by providing a waveform distortion detector, an equalization selector which selects whether a selector should be used at every burst based on the detection of the detector, and an equalizer which compensates waveform distortion due to a delay wave at need. CONSTITUTION:The impulse response h(n) of a reception signal inputted to a distortion detector 14 on a line including the feature of a transmission/ reception filter can be estimated by taking cross-correlation with a reference signal 13 by the detector 14. It is converted to frequency characteristic by taking the sum of h (n) xexp (-jomegaX time difference between a first component and an n-th component, omega= angular frequency). Thereby, a notch is generated when fading with frequency selectivity occurs, however, distortion is compensated by selecting the equalizer 16 by assuming that the fading exists only when such value exceeds a threshold value. When no fading occurs, demodulation is performed by a demodulator 12 of common usage, and the mean computing quantity can be reduced, and the low power consumption can be attained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, due to the rapid increase in demand for mobile communication, digitalization thereof has been rapidly advanced, and in order to realize this, it is necessary to overcome waveform distortion due to frequency selective fading due to delayed waves. Therefore, a method of compensating for waveform distortion by using an equalizer in a receiver is widely used. However, in mobile communication, it is essential to reduce power consumption because the power source is a battery. Therefore, it is essential to reduce power consumption while maintaining the effect of waveform distortion compensation.

Next, a conventional data receiving apparatus will be described. FIG. 3 shows a schematic configuration of a conventional data receiving device. In FIG. 3, 1 is a receiving antenna. A demodulator 2 performs conventional demodulation. Reference numeral 3 is a reference signal. An error detector 4 detects an error based on the reference signal 3. Reference numeral 5 denotes an equalizer selector, which selects whether or not to use the equalizer 6. Reference numeral 7 is received data.

Next, the operation of this conventional structure will be described. First, the received signal received by the receiving antenna 1 is demodulated by the demodulator 2. The reference signal 3 which is known on the receiving side is inserted into the transmission signal on the transmitting side and transmitted. Therefore, the error detector 4 detects the number of errors by comparing only the portion of the reference signal 3 in the demodulated data with the reference signal 3.
The number of errors is compared with the threshold value determined by the equalization selector 5,
If there are many errors, an equalizer is used for output. When there are not many errors, the output of the demodulator 2 is used as the received data 7.

[0005]

However, in the above conventional data receiving apparatus, the equalizer and the normal demodulator are selected only by the number of errors of the reference signal 3. Therefore, if there are many errors due to thermal noise without waveform distortion, an equalizer will be selected. Further, since the reference signal 3 has a small number of bits, the accuracy of the error rate of the reference signal portion is low, and therefore, the equalizer is not selected even if there is waveform distortion, or the equalizer is selected even if there is little waveform distortion. It easily happens. Therefore, it is difficult to obtain the effect of reducing the power consumption, and there is a problem that the performance further deteriorates.

The present invention solves the above problems in the prior art, and an object of the present invention is to provide an excellent data receiving apparatus capable of reducing the average calculation amount and power consumption without degrading the performance. And

[0007]

In order to achieve the above object, the data receiving apparatus of the present invention uses a distortion detecting means for detecting waveform distortion and an equalizing means using the result of the detecting means. Is provided for each burst, equalization means for compensating for waveform distortion due to delayed waves, and demodulation means for performing conventional demodulation are provided, and there is little waveform distortion that does not require the use of equalization means. For the burst, only the demodulation means is used to reduce the calculation amount.

Further, the distortion detecting means stores the frequency characteristic when there is no distortion, the sum of square errors between the stored frequency characteristic and the frequency characteristic estimated from the received signal is obtained, and the equalization selecting means determines the magnitude of the sum. This is a configuration in which the equalizing means is selected when the sum of squared errors is larger than the predetermined threshold value.

In this structure, when the frequency characteristic of the line is estimated from the received signal, the known reference signal is inserted into the transmitted signal at the transmitting side and the received signal is inserted at the receiving side. The cross-correlation with the reference signal is obtained and the impulse response h (n) of the line is calculated as h (n) × exp (−jω
The configuration is such that the sum of the time difference between the x-th component and the n-th component, ω = angular frequency) is added to convert to the frequency characteristic, and the frequency characteristic estimated from the received signal when the squared error is obtained is calculated. This configuration is used by normalizing with the output of the maximum component among the estimated components of the impulse response.

[0010]

With such a configuration, the data receiving apparatus of the present invention compensates the waveform distortion due to the frequency selective fading due to the influence of the delayed wave by using the equalizing means when the received signal is largely distorted, and When the distortion is small, the demodulation is performed only by the conventional demodulation means, so compared to the case where the equalization means is used for all bursts, the average calculation amount is reduced without degrading the performance, Power consumption is reduced.

[0011]

Embodiments of the data receiving apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment. In FIG. 1, 11 is a receiving antenna, 12 is a demodulator for performing conventional processing, 13 is a reference signal, 14 is a distortion detector, 15 is an equalizer selector, 16 is an equalizer, and 17 is received data. .

Next, the operation of the configuration of this embodiment will be described. First, the received signal received by the receiving antenna 11 is input to the distortion detector 14. At the transmission side, the known reference signal 13 is inserted into the transmission signal and transmitted at the reception side. Therefore, the distortion detector 14 obtains a cross-correlation between the reception signal and the reference signal 13 so that the line including the characteristics of the transmission / reception filter can be obtained. The impulse response h (n) can be estimated and converted to frequency characteristics by taking the sum in the following equation (1).

H (n) × exp (−jω × time difference between the first component and the nth component) (1) ω: angular frequency In this case, the frequency characteristic in the case where there is no waveform distortion is shown in FIG.
It is as shown in (a).

When there is frequency selective fading, a notch occurs as shown in FIG. 2B, and the equalizer 16 is required only in such a case. The distance between (a) and the frequency characteristic estimated from the received signal, that is, the squared error between the predetermined frequency interval and the frequency characteristic estimated from the received signal is obtained, and the sum distance is obtained. Then, the equalizer / selector 15 selects the equalizer 16 considering that the frequency selective fading exists only when the value exceeds a predetermined threshold value. When the equalizer 16 is selected, the amount of calculation is large, but the received data 17
Is compensated for the influence of frequency selective fading, and when it is not selected, there is no frequency selective fading, so that it is demodulated by the conventional demodulator 12 as it is, and the amount of calculation can be reduced.

As described above, according to the present embodiment, since the distortion detector 14 detects the distortion of the line and the equalizer / selector 15 selects the equalizer 16 and the normal demodulator 12, the reference signal Compared with the case where the number of errors is detected in the part, the equalizer can be selected depending on the presence / absence of waveform distortion, and the accuracy of the selection of the equalizer can be increased.

[0017]

As is apparent from the above description, the data receiving apparatus of the present invention compensates the waveform distortion due to the frequency selective fading due to the influence of the delayed wave by using the equalizing means when the received signal has a large distortion. However, when the distortion of the received signal is small, demodulation is performed by a normal demodulation means, so that the average calculation amount can be calculated without degrading the performance as compared with the case where the equalization means is used for all bursts. This has the effect of reducing power consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a data receiving apparatus of the present invention.

2A is a frequency characteristic diagram in the case where there is no waveform distortion, FIG. 2B is a frequency characteristic diagram in the case where there is no waveform distortion, and FIG. 2B is a frequency characteristic diagram in the case where there is frequency selective fading.

FIG. 3 is a block diagram showing a configuration of a conventional data receiving device.

[Explanation of symbols]

 11 reception antenna 12 demodulator 13 reference signal 14 distortion detector 15 equalization selector 16 equalizer 17 received data

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Honma 4-3-1, Tsunashima-higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd.

Claims (4)

[Claims] 1. A distortion detection means for detecting waveform distortion, an equalization selection means for selecting whether or not to use the equalization means for each burst by using a result of the detection means, and a waveform distortion due to a delayed wave are compensated. And a demodulation unit for performing conventional demodulation, and for a burst with less waveform distortion that does not require the use of the equalization unit, it is possible to reduce the calculation amount by using only the demodulation unit. Characteristic data receiving device. 2. The distortion detecting means stores the frequency characteristic when there is no distortion, the sum of squared errors between the stored frequency characteristic and the frequency characteristic estimated from the received signal is obtained, and the equalization selecting means determines the magnitude of the sum. 2. The data receiving apparatus according to claim 1, wherein the equalizing means is selected when the sum of squared errors is larger than a predetermined threshold value. 3. When estimating a frequency characteristic of a line from a received signal, a transmitter inserts a reference signal known in the receiver into the transmitted signal, and the receiver inserts the received signal and the inserted reference signal into the transmitted signal. Impulse response h of the line for cross-correlation
As (n), a sum of h (n) × exp (−jω × time difference between the first component and the nth component, ω = angular frequency) is added to convert to a frequency characteristic. Item 2. The data receiving device according to item 2. 4. The data according to claim 2, wherein the frequency characteristic estimated from the received signal is normalized by the output of the largest component of the estimated impulse response when the squared error is obtained. Receiver.