KR20080097621A - Apparatus for removing reverse noise in frequency band and wireless signal transceiver system having the same - Google Patents

Abstract

An apparatus for removing reverse noises within a frequency band and a wireless signal transmitting/receiving system having the same are provided to improve the quality of a communication service by actively coping with the reverse noises generated from the spot. An apparatus(130) for removing reverse noises comprises the followings: an A/D converter(131) outputting the first signal obtained by converting an output signal of a low noise amplifier(120) in a digital type; a correlator(132) outputting only the second signal(noise signal) after dividing the first signal outputted from the A/D converter into a target reception signal(the third signal) and the noise signal(the second signal); a digital processing part(133) which outputs the third signal corresponding to the target reception signal by using the first signal outputted from the A/D converter and the second signal outputted from correlator; and a D/A converter(134) which converts the third signal(the target reception signal) outputted from the digital processing part into an analog signal and outputs it.

Description

Apparatus for Removing Reverse Noise in Frequency Band and Wireless Signal Transceiver System having the Same}

1 is a block diagram of a conventional wireless signal transmission and reception system,

2 is a block diagram of a wireless signal transmission and reception system according to an embodiment of the present invention;

3 is a block diagram of an in-band reverse noise removing apparatus according to an embodiment of the present invention;

4 is a diagram illustrating a first embodiment of the digital processing unit of FIG. 3;

5 illustrates a second embodiment of the digital processing unit of FIG. 3;

6 is a diagram illustrating a third embodiment of the digital processing unit of FIG. 3.

<Description of Symbols for Main Parts of Drawings>

110 filter 120 low noise amplifier (LNA)

130: noise canceller 131: A / D converter

132: correlator 133: digital processing unit

134: D / A converter 140: receiver

The present invention relates to an in-band reverse noise canceling apparatus and a wireless signal transmission / reception system having the same. More particularly, the in-band reverse noise eliminates in-band noise that is relatively stable to time variation, thereby improving the signal-to-noise ratio of the reverse signal. The present invention relates to a removal device and a wireless signal transmission / reception system having the same.

In the wireless communication business, mobile operators are demanding better signal-to-noise ratio (SNR) to secure wide coverage and communication quality, and use expensive power amplifiers and low-noise generators that output high outputs.

Nevertheless, noise at the receiving end of a wireless signal transmission / reception system such as a base station or a repeater limits the reverse coverage and causes a deterioration in communication quality by degrading a signal-to-noise ratio of a signal.

As shown in FIG. 1, the signal receiver of the conventional wireless signal transmission / reception system includes a filter 11, an LNA 12, and a receiver 13 such as a transceiver or a driving amplifier. The filter 11 removes unnecessary noise, but filters only out-of-band frequency components, so that in-band noise components are passed through and are amplified through the LNA 12.

On the other hand, there are many kinds of noises such as noise caused by oscillating RF repeater, computer equipment such as computer, noise caused by TV equipment, and many other sources. To eliminate this effect, mobile operators had to consider the inefficiency and manpower loss of investigating the cause by investing a lot of people, equipment and time.

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, the in-band reverse noise removing device to remove the in-band reverse noise by using a property that the noise generated in the band is relatively stable to the time change. And to provide a wireless signal transmission and reception system having the same.

In addition, the present invention distinguishes a signal from noise through a correlation method of digital processing technology, removes noise from a received signal by adding an inverse phase of the separated noise components, or removes noise using an adaptive filtering technique. An object of the present invention is to provide an in-band reverse noise canceling apparatus for canceling backward noise and a wireless signal transmission / reception system having the same.

In addition, the present invention provides an in-band reverse noise canceling apparatus and a wireless signal transmission and reception system having the same, which can actively cope with the reverse noise generated in the field by removing the in-band reverse noise, thereby securing communication quality and Another aim is to help reduce operating costs.

The present invention for achieving the above object is a filter for removing the frequency out of the reception band from the received signal and output; A low noise amplifier for amplifying the output signal of the filter; A noise removing device which removes noise in a reception band from an output signal of the low noise amplifier and outputs only a target reception signal to a receiving end; It provides a wireless signal transmission and reception system having an in-band reverse noise canceller comprising a.

In addition, to achieve the above object, the present invention is an in-band reverse noise removing device for removing the received in-band noise from the reverse wireless reception signal, and the A / D converter for outputting the first signal converted into a digital signal; ; A correlator for separating the first signal output from the A / D converter into a target received signal and a noise signal, and outputting only the noise signal as a second signal; A digital processing unit which outputs a third signal corresponding to a target reception signal by using the first signal output from the A / D converter and the second signal output from the correlator; A D / A converter converting the third signal output from the digital processing unit into an analog signal and outputting the analog signal; It provides an in-band reverse noise cancellation device comprising a.

Details of the above object and technical configuration of the present invention and the resulting effects thereof will be more clearly understood from the following detailed description based on the accompanying drawings.

First, Figure 2 is a block diagram of a wireless signal transmission and reception system according to an embodiment of the present invention.

As shown, the wireless signal transmission and reception system of the present invention is a filter 110 for removing and outputting out-of-receive band frequency from the received signal, low noise amplifier 120 for amplifying the output signal of the filter 110, low noise amplified And a system receiver 140, such as a base station transceiver block or a repeater drive amplifier, to remove the noise from the signal and provide the received signal to the receiver 140. The amplifier 120 And the noise canceller 130 is interposed between the receiver 140 and the receiver 140.

That is, in the conventional reverse path, even if the in-band noise occurs, the filter does not suppress the in-band, so that both the target signal and the noise are introduced to deteriorate the signal-to-noise ratio. However, in the present invention, the noise canceller 130 includes the low noise amplifier ( The noise in the reception band is removed from the output signal of 120, and only the target reception signal is output to the receiver 140 to improve the signal-to-noise ratio.

To this end, the noise canceller 130 of the present invention has a correlation of 0 because the received signal does not have a correlation with a change in time, but the received signal takes advantage of the property that the noise does not change significantly with a change in time. It removes the noise signal from the signal and utilizes signal correlation and digital processing techniques.

3 is a block diagram of an in-band reverse noise removing apparatus according to an embodiment of the present invention.

As shown, the reverse noise canceller 130 of the present invention is the A / D converter 131, the A / D converter 131 to output the first signal obtained by converting the output signal of the low noise amplifier 120 into a digital signal Correlator 132 and the A / D converter 131 which separates the first signal output from the target signal into a target signal (third signal) and a noise signal (second signal), and outputs only the noise signal as a second signal. A digital processing unit 133 for outputting a third signal corresponding to a target reception signal using the first signal output from the second signal and the second signal output from the correlator 132, and output from the digital processing unit 133. And a D / A converter 134 for converting and outputting a third signal (target reception signal) to an analog signal.

The correlator 132 generates a virtual noise signal, that is, a second signal, based on a signal input from the A / D converter 131 using the property that the noise signal is relatively constant with respect to a change in time. That is, the correlator 132 correlates a previously received signal (signal samples) and a currently received signal (noise signal + target received signal) to detect a virtual noise signal.

The digital processing unit 133 receives a received signal from the A / D converter 131, that is, a first signal, receives a second signal from the correlator 132, and uses the inputted first and second signals. A third signal from which the actual noise is removed from the first signal is output, and the third signal is converted into an analog signal by the D / A converter 134 and input to the receiver 140.

Meanwhile, digital processing techniques include a method and a filtering method utilizing correlation between two signals, which will be described below with reference to FIGS. 4 to 6.

FIG. 4 is a diagram illustrating a first embodiment of the digital processing unit of FIG. 3 and relates to a digital filtering technique using correlation of a signal.

As shown, the digital processing unit 133-1 of FIG. 4 is implemented by an antiphase combiner, and the antiphase combiner inputs a noise signal generated separately by a correlator and a received signal (received signal + noise) as an input. To output only the target received signal from which the noise signal is removed.

That is, the anti-phase combiner detects the correlation between the first signal output from the A / D converter 131 and the second signal output from the correlator 132 to detect an antiphase signal of the noise signal included in the first signal. The target received signal is extracted by generating and combining the first signal with the first signal, and the inband reverse noise signal is removed by providing the received signal to the receiver.

Next, FIG. 5 is a diagram illustrating a second embodiment of the digital processing unit, and FIG. 6 is a diagram showing a third embodiment of the digital processing unit and illustrates an embodiment using a filtering technique.

The digital processing unit 133-2 of FIG. 5 is implemented using a Wiener filter. A Wiener filter is a filter that transforms an input as close as possible to the desired output, where 'as close as possible' means that the square of the difference between the two input signals is minimal. Also called least-squares filter.

That is, the Wiener filter is an algorithm that minimizes the square of the difference between the noise component when the signal and the noise coexist in the input terminal, and is mainly applied to a time invariant system. In the present invention, the Wiener filter is output from the correlator 132. Coefficient value W is used to minimize the mean square error between the second signal corrected by the Wiener filter and the corrected second signal and the first signal output from the A / D converter 131. The second signal output from the correlator 132 is filtered (corrected).

Accordingly, the digital processing unit 133-2 according to the present embodiment is the signal filtered by the Wiener filter, that is, the corrected second signal and the first signal input from the A / D converter 131 (target signal + noise). By combining, the target signal (target reception signal) with the in-band reverse noise removed as much as possible is output.

On the other hand, since the present invention is applied to a wireless signal transmission and reception system, the antenna is installed outdoors, such that the Doppler effect due to the surrounding moving object is generated. Accordingly, the digital processing unit may be implemented by using an adaptive filter suitable for time variation rather than the Wiener filter, which is illustrated in FIG. 6.

The digital processing unit 133-3 of FIG. 6 is implemented by an adaptive filter, and the adaptive filter is an average square of the corrected second signal and the first signal (target signal + noise) output from the A / D converter 131. The filter that filters the second signal (noise) using the coefficient value (W) to minimize the error is the same as the Wiener filter, and the Wiener filter determines the coefficient value at a certain time interval, while the adaptive filter Performs adaptive filtering on time variation by determining coefficient values in units of signal samples.

In addition, the digital processing unit 133-3 of the present embodiment also uses the signal filtered by the adaptive filter and the first signal (target signal + noise) input from the A / D converter 131 as in the embodiment of FIG. By combining the signal to provide the target signal (target receiving signal) from which the noise is removed as much as possible.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Therefore, according to the in-band reverse noise removing apparatus and the wireless signal transmission and reception system having the same, it is possible to remove the in-band noise of the reverse received signal, thereby improving the signal-to-noise ratio, thereby improving the communication quality You can expect

In addition, according to the present invention, it is possible to proactively cope with the reverse noise generated in the field, which can contribute not only to securing the quality of the communication service but also to reducing the operating cost.

Claims (14)

In a wireless signal transmission and reception system, A filter which removes and outputs out-of-receive band frequencies from the received signal; A low noise amplifier for amplifying the output signal of the filter; A noise removing device which removes noise in a reception band from an output signal of the low noise amplifier and outputs only a target reception signal to a receiving end; Wireless signal transmission and reception system having an in-band reverse noise canceller, characterized in that it comprises a. The method of claim 1, The noise canceling device, An A / D converter for outputting a first signal obtained by converting an output signal of the low noise amplifier into a digital signal; A correlator for separating the first signal output from the A / D converter into a target received signal and a noise signal, and outputting only the noise signal as a second signal; A digital processing unit which outputs a third signal corresponding to a target reception signal by using the first signal output from the A / D converter and the second signal output from the correlator; A D / A converter converting the third signal output from the digital processing unit into an analog signal and outputting the analog signal; Wireless signal transmission and reception system having an in-band reverse noise canceller, characterized in that it comprises a. The method of claim 2, The digital processing unit, Detects a correlation between a first signal output from the A / D converter and a second signal output from the correlator to generate an antiphase signal of a noise signal included in the first signal, and generates the antiphase signal And a reverse phase combiner for outputting a target received signal by combining the first signal. The method of claim 2, The digital processing unit, The first signal output from the A / D converter and the second signal output from the correlator are input to correct the second signal so that the mean square error between the first signal and the corrected second signal is minimized. And generating a third signal by combining the corrected second signal and the first signal, and outputting a third signal. The method of claim 4, wherein The digital processing unit, And a Wiener filter for minimizing the mean square error between the corrected second signal and the first signal. The method of claim 4, wherein The digital processing unit, And an adaptive filter for calculating a filter coefficient for minimizing the mean square error between the corrected second signal and the first signal, in units of samples. The method according to any one of claims 1 to 6, The receiving end, A wireless signal transmission / reception system having an in-band reverse noise canceller, characterized in that it is one of a transceiver block of a base station and a drive amplifier of a repeater. An in-band reverse noise removing device for removing received in-band noise from a reverse wireless received signal, An A / D converter for outputting a first signal obtained by converting a received signal into a digital signal; A correlator for separating the first signal output from the A / D converter into a target received signal and a noise signal, and outputting only the noise signal as a second signal; A digital processing unit which outputs a third signal corresponding to a target reception signal by using the first signal output from the A / D converter and the second signal output from the correlator; A D / A converter converting the third signal output from the digital processing unit into an analog signal and outputting the analog signal; In-band reverse noise removing device comprising a. The method of claim 8, The digital processing unit, Detects a correlation between a first signal output from the A / D converter and a second signal output from the correlator to generate an antiphase signal of a noise signal included in the first signal, and generates the antiphase signal And an antiphase combiner for outputting a target received signal by combining the first signal. The method of claim 8, The digital processing unit, The first signal output from the A / D converter and the second signal output from the correlator are input to correct the second signal so that the mean square error between the first signal and the corrected second signal is minimized. And generating and outputting a third signal by combining the corrected second signal and the first signal. The method of claim 10, The digital processing unit, And a Wiener filter for minimizing the mean square error between the corrected second signal and the first signal. The method of claim 10, The digital processing unit, And an adaptive filter for calculating a filter coefficient for minimizing the mean square error between the corrected second signal and the first signal in units of samples. The method according to any one of claims 8 to 12, The in-band reverse noise canceller, An in-band reverse noise removing device interposed between a low noise amplifier (LNA) and a transceiver block of a base station to remove a noise signal from an output signal of the low noise amplifier and input the same into a transceiver block. The method according to any one of claims 8 to 12, The in-band reverse noise canceller, An in-band reverse noise removing device interposed between a low noise amplifier (LNA) of a repeater and a drive amplifier, and removes a noise signal from an output signal of the low noise amplifier and inputs the same to a drive amplifier.

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