KR100988358B1 - Materializing embodiment method for mobile ics repeater - Google Patents

Abstract

The present invention relates to a radio interference cancellation repeater used in a mobile communication system. The present invention provides a wireless interference elimination repeater that effectively filters noise in a signal from which interference is removed by using a detector using a high resolution algorithm such as MUSIC. According to the present invention, the performance of the interference elimination repeater is improved, the cell radius of the base station is expanded, and there is an effect that a stable service can be provided to a mobile communication user.

Interference Cancellation, MUSIC, FA, Detection, FA Bandpass Filter

Description

Implementation method of wireless interference elimination repeater {MATERIALIZING EMBODIMENT METHOD FOR MOBILE ICS REPEATER}

The present invention relates to a radio interference cancellation repeater used in a mobile communication system.

In general, a mobile communication system attempts to satisfy a service quality of a mobile communication in a corresponding area by constructing a repeater in an area covering a radio shade area or a burden of installing a base station.

The repeater is divided into a wired repeater connected to a base station wirelessly, such as an optical cable, and a wireless repeater connected to a base station wirelessly.

The wired repeater can maintain good call quality because wired communication is performed between the repeater and the base station. However, the wired repeater is more expensive than the wireless repeater. On the contrary, since the wireless repeater performs wireless communication between the repeater and the base station, the call quality is lower than that of the wired repeater, but the installation and operation costs are inexpensive. Therefore, when the electromagnetic wave is shielded by the structure such as the basement inside the building, it is expensive. It can be used more appropriately than wired repeater.

However, if the wireless repeater is installed in an open area, not inside the building, part of the transmission signal through the transmission antenna of the wireless repeater is fed back to the reception antenna and mixed with the original reception signal, thereby causing interference or oscillation of the signal. Not only does this happen, it can't provide services, and in the worst case, it can cause a base station failure. Due to this problem, the wireless repeater has been used only in limited places such as the basement inside the building as described above.

However, the advantages of the wireless repeater that the installation and operation cost is cheaper than the wired repeater is still attractive, and the technology that can eliminate the interference of the feedback signal has emerged. The wireless repeater to which the present technology is applied is called a radio interference cancellation repeater or an interference cancellation system (ICS) repeater.

1 is a block diagram showing a conventional radio interference elimination repeater.

The conventional wireless interference elimination repeater, the donor antenna 10, the receiver 20, the A / D converter 30, the band pass filter 40, the interference signal remover 50, the band pass filter 60 , A D / A converter 70, a transmitter 80, and a service antenna 90.

The donor antenna 10 receives the RF signal from the base station and outputs it to the receiver 20.

The receiver 20 receives a signal received from the donor antenna 10, amplifies, downconverts, and filters the output signal to the terminal.

The A / D converter 30 converts the analog signal output from the receiver 20 into a digital signal and outputs the digital signal.

The band pass filter 40 filters only the frequencies required for each FA (Frequency Assignment) in the digital signal converted by the A / D converter 30.

The interference signal removing unit 50 estimates the interference signal using an adaptive filter such as a Least Mean Squire (LMS) or Recursive Least Squire (RLS) algorithm, and removes the interference signal included in the received signal.

The bandpass filter unit 60 cleans up the frequency spectrum of the signal by removing small oscillation components that may occur outside the passband from the signal from which the interference signal is removed.

The D / A converter 70 converts the digital signal arranged by the band pass filter 60 into an analog signal and outputs the analog signal.

The transmitter 80 up-converts, filters, and amplifies the analog signal converted by the D / A converter 70 to service the service antenna 90.

The service antenna 90 receives a signal from the transmitter 80 and transmits the signal to the terminal.

However, when the reception sensitivity of the signal input from the base station is very low, it is difficult to distinguish between the normal signal and the noise level from the frequency characteristics of the existing time domain signal. The problem is that it doesn't work properly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide a wireless interference elimination repeater capable of detecting a normal signal and removing an interference signal even at the lowest reception level.

In order to achieve this object, the present invention, the interference signal removing step of removing the interference signal from the received signal; A noise removing step of determining a noise level for each FA of the signal that has undergone the interference signal removing step and cutting off a FA signal having a noise level of a predetermined value or more; And a transmitting step of transmitting the signal which has passed the noise removing step. It provides a method for implementing a wireless interference cancellation repeater comprising a.

In this case, the noise removing step is a detection step of detecting a parameter for determining whether the signal passed through the interference signal removing step, FA (Frequency Assignment) bandpass filtering; And an FA bandpass filtering step of filtering only the FA signal corresponding to the parameter detected by the detection step by inputting the signal that has passed the interference signal removing step. It provides a method for implementing a wireless interference cancellation repeater comprising a.

The detecting step may include a matrix generation step of generating a correlation matrix for the input signal; An eigen step of obtaining eigenvalues and eigenvectors from the correlation matrix generated in the matrix generation step; A separation step of finding a position for separating a signal and a noise space from the distribution of eigenvalues obtained in the eigen steps; Calculating a dot product of the signal space portion and the noise space portion using the eigenvectors obtained in the eigen steps; A spectral step of obtaining a spectral distribution using an inverse of the inner product obtained in the calculation step; And a parameter detecting step of detecting a parameter by finding an FA to be subjected to FA bandpass filtering in the spectral distribution obtained in the spectral step. It provides a method for implementing a wireless interference cancellation repeater comprising a.

On the other hand, the receiving unit for receiving a signal; An interference signal removing unit for removing the interference signal from the signal output from the receiving unit; A noise removing unit for determining a noise level for each FA of the signal from which the interference signal has been removed by the interference signal removing unit to block an FA signal having a noise level equal to or greater than a predetermined value; A transmitter for transmitting a signal output from the noise canceling unit; It provides a wireless interference cancellation repeater comprising a.

The noise canceling unit detects a parameter for determining FA bandpass filtering by searching for an FA that requires FA bandpass filtering using a correlation matrix of the input signal. Detection unit; And an FA bandpass filter unit for inputting a signal output from the interference signal removing unit to filter only the FA signal corresponding to the parameter detected by the detector. It provides a wireless interference cancellation repeater comprising a.

In this case, the FA bandpass filtering unit provides a wireless interference elimination repeater, characterized in that it comprises a plurality of FA bandpass filters for filtering the corresponding FA signal by the parameters detected by the detection unit.

As described above, according to the present invention, by improving the reception sensitivity of the signal by using a high resolution algorithm, the performance of the interference cancellation repeater is improved, the cell radius of the base station can be extended, and the stable service can be provided to the mobile communication user. There is.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

<Description of Configuration>

2 is a block diagram showing a radio interference cancellation repeater of the present invention.

The wireless interference elimination repeater of the present invention is a donor antenna 110, a receiver 120, an A / D converter 130, a band pass filter 140, an interference signal remover 150, a detector 160, FA The band pass filter unit 170, the D / A converter 180, the transmitter 190 and the service antenna 200 is composed of.

The donor antenna 110 receives the RF signal from the base station and outputs it to the receiver 120.

The receiver 120 receives a signal received from the donor antenna 110, amplifies, downconverts, and filters the output signal to the terminal.

The A / D converter 130 converts the analog signal output from the receiver 120 into a digital signal and outputs the digital signal.

The band pass filter 140 filters only frequencies required for each FA in the digital signal converted by the A / D converter 130.

The interference signal removing unit 150 estimates the interference signal by using an adaptive filter such as an LMS or RLS algorithm, and removes the interference signal included in the received signal.

The detection unit 160 receives a signal output from the interference signal removing unit 150 and detects a parameter for determining whether FA bandpass filtering exists for each FA. The detection method according to an embodiment of the present invention uses a MUSIC algorithm. Is done.

That is, a correlation matrix is generated for the input signal to obtain an eigenvalue and an eigenvector from the correlation matrix, and find a position separating the signal and the noise space from the distribution of the eigenvalues. The inner product of the signal space and the noise space is obtained using the eigenvectors, and then the spectral distribution is obtained using the inverse of the inner product. At this time, the normal signal and noise can be clearly distinguished from the spectral distribution of the signal. Assuming that a FA having a value exists, the presence or absence of FA bandpass filtering may be determined due to parameters of FA values having a value higher than a reference value.

In this case, the detection method may determine whether filtering is performed using a high resolution algorithm such as Eigenvalue and SVD (singular value decomposition) instead of the MUSIC algorithm.

The FA bandpass filtering unit 170 includes a plurality of FA bandpass filters, and each FA bandpass filter includes a FA signal whose noise level is determined to be higher than a predetermined value (reference value) based on a parameter detected by the detector. Do not filter. That is, only the FA bandpass filter corresponding to the FA whose noise level is determined to be lower than a predetermined value among the plurality of FA bandpass filters by the parameters of the FA values detected by the detector performs a filtering operation.

The D / A converter 180 converts the band-pass filtered digital signal for each FA by the FA bandpass filtering unit 170 into an analog signal.

The transmitter 190 filters, upconverts, and amplifies the analog signal converted by the D / A converter 180 and outputs the analog signal to the service antenna 200.

The service antenna 200 transmits a signal received from the transmitter 190 to the terminal side.

<Description of the method>

A signal relay method by the wireless interference elimination repeater of FIG. 2 having the above configuration will be described with reference to the flowchart of FIG.

1. Receive step <S310>

The donor antenna 110 receives the RF signal, amplifies and downconverts the IF signal, and then outputs the filtered signal.

2. A / D conversion step <S320>

The A / D converter 130 converts the analog signal output in step S310 into a digital signal and outputs the digital signal.

3. Filtering step <S330>

The band pass filter 140 filters only frequencies required for each FA in the digital signal output in step S320.

4. Interference signal elimination step <S340>

The interference signal removing unit 150 estimates the interference signal from the signal filtered in step S330 by using an adaptive filter such as an LMS or RLS algorithm, removes the interference signal included in the received signal, and then removes the interference signal. Are input to the detector 160 and the FA band pass filtering unit 170, respectively.

5. Detection step <S350>

Some of the signals that have passed through step S340 are input to the detection unit 160 to detect a parameter for determining whether or not the signal is filtered in each FA bandpass filter of the FA bandpass filtering unit 170.

At this time, the detection method according to an embodiment of the present invention is performed by the MUSIC algorithm. First, a correlation matrix of an input signal is obtained (S351), and an eigenvalue and an eigenvector are obtained from the matrix (S352). From the obtained eigenvalues, we obtain a position value that separates signal and noise spaces (S353), and to obtain the spectral distribution of signal components corresponding to the position values (S355). Calculate the inner product of and use the inverse of the inner product (S354). Therefore, the spectral distribution obtained as described above can be clearly distinguished from noise. In this case, if there is an FA having values higher than a reference value, an FA for performing FA bandpass filtering can be found in the spectral distribution, and corresponding By detecting a parameter of the FA value (S356), it is possible to determine whether the parameters are FA bandpass filtering.

Of course, the detection method is the same as above. High-resolution algorithms such as Eigenvalue and SVD, rather than MUSIC algorithm, can be used to determine the filtering.

6. FA bandpass filtering step <S360>

Each FA bandpass filter of the FA bandpass filtering unit 170 performs bandpass filtering of signals corresponding to the signals in the signal passing through step S340 for each FA using the parameters detected in step S350, and the noise level is greater than a predetermined value. The FA signal determined to be high is not filtered, and only the FA bandpass filter corresponding to the FA whose noise level is determined to be lower than a predetermined value is filtered to improve the sensitivity of the signal.

7. D / A conversion step <S370>

The D / A converter 180 converts the digital signal filtered in step S360 into an analog signal.

8. Sending step <S380>

The transmitter 190 amplifies the analog signal converted in step S370, upconverts the IF signal to an RF signal, and then filters and transmits the same through the service antenna 200.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a block diagram showing a conventional radio interference elimination repeater.

2 is a block diagram showing a radio interference cancellation repeater of the present invention.

3 (a) is a flowchart illustrating a flow for implementing the wireless interference elimination repeater of the present invention.

3B is a flowchart illustrating a flow of generating parameters in the detector of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: wireless interference elimination repeater

120: receiver 130: A / D converter

140: band pass filter 150: interference signal canceller

160: detection unit 170: FA band pass filtering unit

180: D / A converter 190: transmitter

Claims (6)

delete delete An interference signal removing step of removing the interference signal from the received signal; A noise removing step of determining a noise level for each FA of the signal that has undergone the interference signal removing step and cutting off a FA signal having a noise level of a predetermined value or more; And A transmitting step of transmitting the signal which has passed the noise removing step; Including, The noise removing step, A detection step of detecting a parameter for determining whether or not a frequency assignment (FA) bandpass filtering is input by inputting a signal that has undergone the interference signal removing step; And A FA bandpass filtering step of filtering the FA signal only by the parameters detected in the detection step by inputting a signal that has passed the interference signal removing step; Including, The detecting step, A matrix generation step of generating a correlation matrix for the input signal; An eigen step of obtaining eigenvalues and eigenvectors from the correlation matrix generated in the matrix generation step; A separation step of finding a position for separating a signal and a noise space from the distribution of eigenvalues obtained in the eigen steps; Calculating a dot product of the signal space portion and the noise space portion using the eigenvectors obtained in the eigen steps; A spectral step of obtaining a spectral distribution using an inverse of the inner product obtained in the calculation step; And A parameter detecting step of detecting a parameter by finding an FA to perform FA bandpass filtering in the spectrum distribution obtained in the spectral step; Wireless interference elimination repeater implementation method comprising a. delete delete delete

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