KR20170097544A - Interference cancellation repeater and method for operating the same - Google Patents

Abstract

The present invention relates to an interference cancellation relay device using a digital filter, and more specifically, to an interference cancellation relay device which adjusts gains of received RF signals in order to prevent ADC saturation. According to one embodiment of the present invention, the device comprises: an interference signal information generating unit which synchronizes a digital input signal input by a digital filter with a digital output signal output from the digital filter, and generates interference signal information on the basis of the synchronized digital input signal and digital output signal; a control unit which outputs a gain control signal according to the generated interference signal information; and an input attenuation adjusting unit which attenuates gains of receiving signals when the gain control signal output from the control unit is input. Since the interference cancellation relay device accurately calculates interference signals through the synchronization of digital input signals with digital output signals, the device adjusts an amount of attenuation based on the ADC saturation level to prevent the ADC saturation, and maintains a stable service coverage.

Description

TECHNICAL FIELD The present invention relates to an interference cancellation repeater and a method of operating the same,

TECHNICAL FIELD The present invention relates to an interference cancellation relay apparatus using a digital filter, and more particularly, to an interference canceller that adjusts a gain of a received RF signal to prevent ADC saturation.

As the frequency and service bandwidth of the carrier have been changed from time to time, the repeater eliminates the interference except the service signal by using a digital filter having no bandwidth limitation. For example, the repeater removes interference signals, such as signals that are unnecessary signals from other providers and signals fed back from the repeaters, by using a digital filter. Therefore, an analog-to-digital converter (ADC) is required to convert received RF signals (analog signals) into digital signals.

However, if the magnitude of the received interfering signal is greater than the saturation level of the ADC, the function of the ADC may not be performed normally. For example, if the magnitude of the interfering signal is greater than the saturation level of the ADC, the signal beyond the saturation level of the ADC may not be digitally converted normally. Conventional repeaters therefore include an attenuator that attenuates the magnitude of the received signal before analog-to-digital conversion. Here, the attenuator attenuates the composite signal of the received service signal and the interference signal. That is, the attenuating operation of the attenuator attenuates the service signal, and accordingly, the coverage of the service band can be changed.

To solve this problem, there is a technique of estimating the interference signal and controlling the gain so that the output signal of the ADC and the output signal of the digital filter are constantly output. However, it is difficult to accurately estimate the interference signal, and it is not possible to calculate an accurate interference signal, especially when the signal is divided into time intervals, such as a time division multiple access (TDMA) or an LTE burst signal .

Therefore, the interference cancellation relay apparatus needs an alternative for accurately calculating the interference signal to prevent ADC saturation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to prevent an ADC from saturating and to maintain stable service coverage by more accurately calculating an interference signal in a gain control method using an interference signal calculation.

According to an aspect of the present invention, there is provided an apparatus for synchronizing a digital input signal input to a digital filter with a digital output signal output from the digital filter, and generating an interference signal based on the synchronized digital input signal and the digital output signal. A control unit for outputting an input control signal in accordance with the generated interference signal information, and an input for attenuating a reception signal associated with the digital input signal based on the input control signal output from the control unit According to an embodiment of the present invention, the interference signal information generating unit includes a delay unit for delaying the digital input signal by a preset time for synchronizing the digital input signal and the digital output signal, An interference cancellation relay apparatus is provided.

According to an exemplary embodiment, the interference signal information generating unit may include an input signal measuring unit for measuring a first peak value of the digital input signal, an output signal measuring unit for measuring a second peak value of the digital output signal, And generating the interference signal information using the peak value and the second peak value.

According to an exemplary embodiment, the input signal measuring unit and the output signal measuring unit measure the first peak value and the second peak value, and the peak value is measured by synchronizing the first peak value and the second peak value, / RTI >

According to an exemplary embodiment, the interference signal calculator generates the interference signal information based on a difference between the first peak value and the second peak value.

According to an exemplary embodiment, the interference cancellation relay apparatus is provided wherein the interference signal information is generated by the following equation.

는 간섭신호정보를 나타내며, 상기

은 제1 피크값, 상기

은 제2 피크값을 나타낸다.)(Wherein,

Indicates the interference signal information,

Is a first peak value,

Represents a second peak value.)

According to an exemplary embodiment, the interfering signal relay apparatus further includes an ADC for converting the received signal into the digital input signal, wherein the received signal is a signal received from the base station and input to the ADC .

According to an exemplary embodiment, the interfering signal relay apparatus further comprises an output gain control section for controlling a gain of the digital output signal

According to an exemplary embodiment, the control unit outputs an output control signal generated based on the interference signal information, and the output gain control unit controls the gain of the digital output signal based on the output control signal. A relay device is provided.

According to another aspect of the present invention, there is provided a method for controlling a digital filter, comprising the steps of: synchronizing a digital input signal input to a digital filter with a digital output signal output from the digital filter; Generating interfering signal information and attenuating a received signal associated with the digital input signal based on the interfering signal information.

According to an exemplary embodiment, the interference cancellation method further comprises the step of controlling the gain of the digital output signal based on the interference signal information.

The interference cancellation apparatus according to the technical idea of the present invention can precisely calculate the interference signal through synchronization of the digital input signal and the digital output signal so that the saturation of the ADC is prevented by adjusting the attenuation according to the ADC saturation level can do.

In addition, the interference cancellation repeater according to the technical idea of the present invention can maintain the stable service coverage by compensating the attenuated signal at the output terminal for preventing saturation of the ADC.

BRIEF DESCRIPTION OF THE DRAWINGS A brief description of each drawing is provided to more fully understand the drawings recited herein.
1 is a block diagram illustrating a mobile communication system 100 according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of an interference cancellation relay apparatus 120 according to an embodiment of the present invention.
FIG. 3 is a block diagram of an interference signal information generating unit 270 according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an operation of the interference canceller 120 according to an embodiment of the present invention.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. However, it should be understood that the technical idea of the present invention is not limited to the specific embodiments but includes all changes, equivalents, and alternatives included in the technical idea of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0027] In the following description of the present invention, a detailed description of known technologies will be omitted when it is determined that the technical idea of the present invention may be unnecessarily obscured. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

The terms "to", "to", "to", "to", and "module" in the present specification mean units for processing at least one function or operation, A micro processor, a central processing unit (CPU), a graphics processing unit (GPU), an Accelerate Processor Unit (APU), a digital signal processor (DSP), an application specific integrated circuit (ASIC) (Field Programmable Gate Array), or the like, or a combination of hardware and software.

It is to be clarified that the division of constituent parts in this specification is merely a division by each main function of each constituent part. That is, two or more constituent parts to be described below may be combined into one constituent part, or one constituent part may be divided into two or more functions according to functions that are more subdivided. In addition, each of the constituent units described below may additionally perform some or all of the functions of other constituent units in addition to the main functions of the constituent units themselves, and that some of the main functions, And may be carried out in a dedicated manner.

Hereinafter, exemplary embodiments of the present invention will be described in detail.

1 is a block diagram illustrating a mobile communication system 100 according to an embodiment of the present invention.

1, a mobile communication system 100 according to an exemplary embodiment of the present invention includes base stations 110-1 and 110-2 for transmitting service signals and other service provider signals, an interference cancellation relay device 120, And may include a communication terminal 130.

The base stations 110-1 and 110-2 and the interference cancellation relay apparatus 120 may connect the mobile communication network and the mobile communication terminal 130 for mobile communication service. That is, the signal transmitted from the mobile communication terminal 130 is interference canceled and amplified by the interference cancellation repeater 120, and then transmitted through the base stations 110-1 and 110-2 to other mobile communication terminals, for example, Lt; / RTI > A signal transmitted from another mobile communication terminal, for example, a caller terminal (not shown) is transmitted to the interference cancellation repeater 120 via the base stations 110-1 and 110-2, Removed and amplified, and then transmitted to the mobile communication terminal 130. That is, when the distances between the base stations 110-1 and 110-2 and the mobile communication terminal 130 are too long to smoothly transmit signals, the interference cancellation repeater 120 may transmit signals to the base stations 110-1 and 110-2, And can serve as a signal amplification function between the terminals 130.

The interference cancellation relay apparatus 120 may be implemented as a communication apparatus that relays signals between the base stations 110-1 and 110-2 and the mobile communication terminal 130 and removes interference signals. For example, the interference signal may include a signal b transmitted from the second base station 110-2, a signal c fed back from the interference cancellation repeater 120, and the like. The interference cancellation repeater 120 receives a signal (hereinafter referred to as a received signal) including the service signal a and the interference signals (e.g., b and c) and removes the interference signals (e.g., b and c) Only the service signal (a) can be transmitted.

In addition, the interference cancellation relay apparatus 120 prevents the saturation of the ADC by attenuating the received signal having a larger size as the interference signals (for example, b and c) are included, compensates the service signal a by the amount of attenuation, Can be relayed. An interference cancellation relay device 120 that prevents saturation of an ADC (Analog-Digital Converter) will be described in more detail below with reference to FIG. 2 to FIG.

FIG. 2 is a configuration diagram of an interference cancellation relay apparatus 120 according to an embodiment of the present invention.

2, for convenience of explanation, the interference cancellation relay 120 transmits a downlink signal received from the base stations 110-1 and 110-2 to the mobile communication terminal 130 Only those configurations are shown. Since the configurations for transmitting the uplink signals of the mobile communication terminal 130 to the base stations 110-1 and 110-2 may correspond to the configurations for transmitting the downlink signals, A detailed description of the configurations for these components will be omitted.

1 and 2, the interference cancellation repeater 120 includes an RF receiver 210, an input attenuation adjuster 220, an analog-to-digital converter (ADC) 230, a digital filter 240, (Digital-Analog Converter) 260, an interference signal information generating unit 270,

First, the RF receiving unit 210 may receive a reception signal provided from the base stations 110-1 and 110-2 through a plurality of reception antennas of the interference cancellation repeater 120. [ The received signal may include a downlink signal and a plurality of frequency band signals of the base stations 110-1 and 110-2 (see FIG. 1), and may include a feedback signal output from the interference cancellation repeater 120 have.

The RF receiver 210 may be configured to remove the noise of the received signal, frequency-downconvert the noise-removed received signal, and output it. For example, the RF receiver 210 includes a low noise amplifier (LNA) for minimizing noise in a received signal, a low noise amplifier for amplifying a received signal amplified by a low noise amplifier from an RF band signal to an intermediate frequency Frequency down-converter (IF down-converter) for converting an intermediate frequency band signal into an intermediate frequency band (IF band) signal, a frequency down-converter for converting an intermediate frequency band received signal into a baseband signal, And the RF receiving unit 210 can perform signal processing for converting the received signal into the digital signal from the ADC 230 through the RF receiving unit 210.

The input attenuation adjusting unit 220 receives a signal processed by the RF receiving unit 210 (for example, noise cancellation, frequency downconversion, etc.). The input attenuation adjustment unit 220 may adjust the magnitude of the received signal to match the ADC saturation level. The input attenuation adjusting unit 220 will be described in more detail with reference to the configuration (the ADC 230, the control unit 280) associated with the input attenuation adjusting unit 220 hereinafter.

The ADC 230 may convert the attenuated received signal into a digital signal by the input attenuation adjustment unit 220 to remove the interference of the received signal using the digital filter 250. At this time, since the magnitude of the received signal inputted to the ADC 230 is attenuated by the input attenuation adjusting unit 220 in accordance with the saturation level set in the ADC 230, Can be converted into a digital signal and output. A received signal (hereinafter, referred to as a digital input signal) converted into a digital signal by the ADC 230 can be input to the digital filter 240 and the interference signal information generating unit 270.

The digital filter 240 may filter the interference signal included in the digital input signal and output the digital input signal when the digital input signal is input from the ADC 230. In this case, the method of removing the interference signal by the digital filter 240 may be variously implemented. Those skilled in the art will appreciate that the filtering method of the digital filter 240 limits the scope of the present invention. You can easily understand that you can not.

The output gain control unit 250 receives a signal (hereinafter, referred to as a digital output signal) from which interference has been removed from the digital filter, and compensates the size of the digital output signal attenuated by the input attenuation adjustment unit 220 have. According to the embodiment, the magnitude that the output gain adjuster 250 compensates for the digital output signal may be set differently from the attenuation of the input attenuation adjuster 220. The output gain adjuster 250 adjusts the gain of the digital output signal It can be configured as an amplifier for compensation. The DAC 260 converts the digital output signal compensated by the output gain adjusting unit 250 into an analog signal and outputs the analog signal. The analog signal output from the DAC 260 may be transmitted to the mobile communication terminal 130 through a transmitter (not shown).

The interference signal information generating unit 270 receives the digital input signal and the digital output signal, and can generate information on the interference signal (hereinafter, referred to as interference signal information) using the two signals. The interference signal information generating unit 270 may measure the first peak value of the digital input signal and the second peak value of the digital output signal, and generate the interference signal information using the respective peak values. The interference signal information may be generated by a difference between the first peak value and the second peak value. At this time, a time difference may be generated between the digital input signal and the digital output signal input to the interference signal information generating unit 270 by the digital filter 240. The interference signal information generating unit 270 may delay the digital input signal to accurately generate the interference signal information to synchronize the digital input signal and the digital output signal.

The control unit 280 may generate and output a control signal for gain control of the input attenuation adjusting unit 220 and the output gain adjusting unit 250 based on the interference signal information input from the interference signal information generating unit 270 . The control unit 280 outputs a signal for controlling the attenuation amount of the input attenuation adjusting unit 220 to the input attenuation adjusting unit 220 and controls the gain compensation of the output gain adjusting unit 250 (Hereinafter, referred to as an output control signal) to the output gain adjuster 250. For example, when the interference signal information is input from the interference signal information generation unit 270, the control unit 280 outputs an input control signal for preventing saturation of the ADC 230 using the interference signal information to the input attenuation adjustment unit 220 ). When the input control signal is input from the control unit 280, the input attenuation adjustment unit 220 may reduce the size of the received signal to prevent saturation of the ADC 230. For example, when the interference signal information is input from the interference signal information generation unit 270, the control unit 280 outputs an output control signal for compensating for the magnitude of the digital output signal using the interference signal information, (250). When the output control signal is input from the controller 280, the output gain controller 250 compensates for the size of the digital output signal including the service signal (the signal requested by the user terminal 130), thereby enabling smooth communication. Hereinafter, the interference signal information generation unit 270 and the control unit 280 that generate interference signal information by synchronizing the digital input signal and the digital output signal with respect to time will be described in more detail with reference to FIG.

FIG. 3 is a block diagram of an interference signal information generating unit 270 according to an embodiment of the present invention.

2 and 3, the interference signal information generation unit 270 may include a delay unit 310, an input signal measurement unit 320, an output signal measurement unit 330, and an interference signal calculation unit 340 have.

First, the delay unit 310 may delay the digital input signal by a preset time for synchronizing the digital input signal and the digital output signal when the digital input signal is input. The predetermined time for synchronization with the delay unit 310 may be a time delayed by the digital filter 240. [ For example, when the digital filter 240 takes 2 ms to remove and output the interference signal of the digital input signal, the delay unit 310 is preset to delay the digital input signal by 2 ms, .

The input signal measuring unit 320 may measure the first peak value of the digital input signal delayed by the delay unit 310. [ The input signal measuring unit 310 may measure the first peak value for a predetermined time interval when measuring the first peak value. For example, in case of Long Term Evolution (LTE) signal, peak value should be measured for 10 ms at intervals of 1 ms so that accurate peak value can be measured even for the burst signal. The output signal measuring unit 330 may also measure the second peak value of the digital output signal in the same manner as the input signal measuring unit 320. That is, the output signal measuring unit 330 may measure the second peak value for a predetermined time interval when measuring the second peak value. The input signal measuring unit 320 and / or the output signal measuring unit 330 may output information on the measured first peak value and / or second peak value to the interference signal calculating unit 340, respectively.

When the first peak value and / or the second peak value information of the digital input signal and the digital output signal are inputted from the input signal measuring unit 320 and / or the output signal measuring unit 330, And the interference signal information can be generated using the information. The interference signal calculator 340 can generate interference signal information based on the difference between the first peak value of the digital input signal and the second peak value of the digital output signal. That is, the interference signal calculator 340 can generate the interference signal information by comparing the digital input signal, which is a signal before passing through the digital filter 240, with the digital output signal through which the interference is removed through the roll of the digital filter 240 . The interference signal computing section 340 can generate interference signal information based on Equation (1).

는 간섭신호정보를 나타내며,

은 디지털입력신호의 제1 피크값,

은 디지털출력신호의 제2 피크값을 나타낸다. 간섭신호연산부(340)는 간섭신호정보를 생성하여 제어부(280)로 출력할 수 있다.At this time,

Indicates interference signal information,

A first peak value of the digital input signal,

Represents the second peak value of the digital output signal. The interference signal computing unit 340 may generate interference signal information and output the generated interference signal information to the control unit 280.

The controller 280 may generate the input control signal and the output control signal by comparing the interference signal information with a predetermined saturation level of the ADC when the interference signal information is input from the interference signal operation unit 340. [ For example, when the value of the interference signal information is larger than the saturation level of the ADC, the control unit 280 outputs an input control signal for adjusting the amount of attenuation of the input attenuation adjustment unit 220 by a value exceeding the saturation level of the ADC And output it. That is, when the value of the interference signal information is '7' and the saturation level of the ADC is '5', the control unit 280 may generate and output an input control signal for adjusting the attenuation amount of '2' or more. The controller 280 may generate an output control signal corresponding to the input control signal and output the generated output control signal to the output gain controller 250. For example, the control unit 280 may generate and output an output control signal for compensation of '2' by generating and outputting an input control signal for adjusting the amount of attenuation by '2'. That is, the control unit 280 may control the attenuation of the input attenuation adjusting unit 220 and the degree of compensation of the output gain adjusting unit 250. [ The operation of the control unit 280, the input attenuation adjusting unit 220, and / or the output gain adjusting unit 250 will be described in more detail with reference to FIG.

FIG. 4 is a diagram illustrating an operation of the interference canceller 120 according to an embodiment of the present invention.

1 to 4, a reception signal received from the base stations 110-1 and 110-2 may include a service signal S410 and an interference signal S420. According to an embodiment, the interfering signal may be composed of a combination of a plurality of interfering signals. The RF receiving unit 210 may combine the service signal S410 and the interference signal S420 to convert it into a new composite signal S430. The combined signal S430 synthesized by the RF receiver 210 may be input to the input attenuation adjuster 220. [ The input attenuation adjusting unit 220 may attenuate the combining signal S430 so that the input control signal input from the interference signal information generating unit 270 does not exceed the saturation level of the ADC 230. [ The attenuated composite signal S440 may be converted by the ADC 230 to a digital input signal S450.

The digital input signal S450 is input to the digital filter 240 and the digital filter 240 can remove the interference signal included in the digital input signal S450 and output the digital output signal S460. The digital input signal S450 and the digital output signal S460 are input to the interference signal information generating unit 270. The interference signal information generating unit 270 generates a digital input signal S450 and a digital output signal S460, To generate interference signal information. The interference signal information generating unit 270 may generate and output an input control signal and / or an output control signal using the interference signal information.

At this time, the interference signal information generating unit 270 performs time synchronization between the digital output signal S460 delayed by the digital filter 240 and the digital input signal S450 to generate accurate interference signal information . For example, if the digital input signal S450 is input to the digital filter 240 at T1 and the digital output signal S460 is output at the digital filter 240 at T2, the interference signal information generator 270 May delay the digital input signal S450 by a delay in the digital filter 240 to generate the delayed digital input signal DS450. The delay time for delaying the digital input signal S450 by the interference signal information generating unit 270 is expressed by Equation (2).

는 지연시간을 나타내며,

는 디지털출력신호가 출력되는 시간을,

은 디지털입력신호가 입력되는 시간을 나타낸다.At this time,

Represents the delay time,

The time at which the digital output signal is output,

Represents the time at which the digital input signal is input.

That is, the interference signal information generating unit 270 generates the delayed digital input signal DS450 synchronized with the digital output signal S460 and outputs the delayed digital input signal DS450 and / or the digital output signal S460 accurately The interference signal information can be generated.

When the output control signal is input from the interference signal information generating unit 270, the output gain adjusting unit 250 compensates for the attenuation amount of the composite signal S440 attenuated by the input control signal output from the interference signal information generating unit 270 And outputs the digital output signal S470.

In this way, the interference signal information generating unit 270 generates accurate interference signal information through time synchronization between the digital input signal and the digital output signal, and outputs a control signal according to the interference signal information, thereby preventing saturation of the ADC, It is possible to maintain stable coverage.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the technical scope of the present invention is not limited to the above embodiments but may be modified within the scope of the technical idea of the present invention. Various modifications and variations are possible.

100: mobile communication system
110-1 and 110-2:
120: interference cancellation repeater
130: mobile communication terminal
S410: Service signal
S420: Interference signal
S430:
S440: attenuated synthesized signal
S450: Digital input signal
DS450: Delayed digital input signal
S460: Digital output signal
S470: Compensated digital output signal

Claims (11)

An interference signal information generating unit for generating an interference signal information based on the synchronized digital input signal and the digital output signal by synchronizing a digital input signal inputted into a digital filter and a digital output signal outputted from the digital filter;
A controller for outputting an input control signal according to the generated interference signal information; And
An input attenuation adjustment unit for attenuating a reception signal associated with the digital input signal based on the input control signal output from the control unit;
And an interference cancellation relay device.
The method according to claim 1,
Wherein the interference signal information generating unit comprises:
A delay unit for delaying the digital input signal by a predetermined time for synchronizing the digital input signal and the digital output signal;
And an interference cancellation relay device.
The method according to claim 1,
Wherein the interference signal information generating unit comprises:
An input signal measuring unit for measuring a first peak value of the digital input signal;
An output signal measuring unit for measuring a second peak value of the digital output signal; And
An interference signal operating unit for generating the interference signal information using the first peak value and the second peak value;
Further comprising:
The method of claim 3,
Wherein the input signal measurement unit and the output signal measurement unit comprise:
Wherein the first peak value and the second peak value are measured, and the peak value is measured by synchronizing the first peak value and the second peak value by a preset time interval.
The method of claim 3,
The interference signal calculating section calculates,
And generates the interference signal information by a difference between the first peak value and the second peak value.
6. The method of claim 5,
Wherein the interference signal information is generated by the following equation.

(Wherein,

Indicates the interference signal information,

Is a first peak value,

Represents the second peak value.)
The method according to claim 1,
The interference signal relay device includes:
And an ADC for converting the received signal into the digital input signal, wherein the received signal is a signal received from the base station and input to the ADC.
The method according to claim 1,
The interference signal relay device includes:
Further comprising an output gain adjusting section for controlling a gain of the digital output signal.
9. The method of claim 8,

Wherein,
Outputting an output control signal generated based on the interference signal information,
The output gain adjuster includes:
And controls the gain of the digital output signal based on the output control signal.
Synchronizing a digital input signal input to the digital filter with a digital output signal output from the digital filter;
Generating interference signal information based on the synchronized digital input signal and the digital output signal; And
Attenuating a received signal associated with the digital input signal based on the interference signal information;
Wherein the interference cancellation apparatus includes:
11. The method of claim 10,
The method of operation of the interference cancellation repeater,
And controlling the gain of the digital output signal based on the interference signal information.

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