KR101431528B1 - Full Band Duplexer and Radio Communication System Therefor - Google Patents

Abstract

The present invention relates to a full-band duplexer and a wireless communication system therefor.

The present invention relates to a directional coupler for coupling a transmission signal; A transmission A / D converter for receiving the coupled signal and outputting a first signal obtained by converting the coupled signal into a digital signal; A reception A / D converter for outputting a second signal obtained by converting a reception signal into a digital signal; And a mobile communication terminal that communicates with the antenna, estimates a channel between the first signal and the second signal, pre-distorts the first signal, and removes the interference signal included in the second signal using the correlation with the second signal And a digital processing unit for controlling the digital processing unit to output only the target received signal from which the interference signal has been removed to the estimated channel.

According to the present invention, there is no need for a separate guard band, and there is an effect that the guard band can be used for the entire band without need for frequency division or time division.

Full band, duplexer, interference signal, correlation, Wiener filter

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a duplexer and a wireless communication system therefor,

The present invention relates to a full-band duplexer and a wireless communication system therefor. To a full-band duplexer capable of utilizing a full-band without separating a transmission / reception band by outputting a signal obtained by removing an interference signal due to a transmission signal from a reception signal by applying a digital filtering technique, and a wireless communication system therefor.

In order to provide a bidirectional communication service, a mobile communication service provider has to separate transmission / reception channels. The transmission / reception channel separation method has been divided into frequency division duplexing (FDD) and time division duplexing (TDD).

However, if the duplexing method and the dividing method are defined and determined in advance, it is almost impossible to change the duplexing method and the dividing method due to the compatibility problem with the terminal, and the use of radio resources such as frequency and time is restricted come.

Particularly, in the case of the frequency division method, when a mobile communication provider uses a band in which a transmission band and a reception band are continuous rather than a band in which transmission and reception bands are different from each other, a third passive element generated in a passive element such as a feeder line, a distributor, As shown in FIG. 1 due to a problem of PIM (Passive Inter-Modulation), it is unreasonable to have a guard band as much as a transmission signal band.

In order to solve this problem, as shown in FIG. 2, a method has been proposed in which the frequency spacing between the transmitting and receiving bands is narrowed and the passive interference (PIM) generated thereby is removed by using the PIM eliminator to increase the frequency efficiency. There is a disadvantage that a certain degree of guard band is also required.

In order to solve the above-described problems, the present invention provides a full-band duplexer capable of utilizing a full-band without separating a transmission / reception band by outputting a signal obtained by removing an interference signal due to a transmission signal from a reception signal by applying a digital filtering technique It has its purpose.

According to an aspect of the present invention, there is provided a mobile communication system including: a directional coupler coupling a transmission signal; A transmission A / D converter for receiving the coupled signal and outputting a first signal obtained by converting the coupled signal into a digital signal; A reception A / D converter for outputting a second signal obtained by converting a reception signal into a digital signal; And a mobile communication terminal that communicates with the antenna, estimates a channel between the first signal and the second signal, pre-distorts the first signal, and removes the interference signal included in the second signal using the correlation with the second signal And a digital processing unit for controlling the digital processing unit to output only the target received signal from which the interference signal has been removed to the estimated channel.

According to another aspect of the present invention, there is provided a digital signal processing method comprising the steps of: coupling a transmission signal and converting the digital signal into a first signal, converting the received signal into a second signal, A full-band duplexer for outputting only the target received signal from which the interference signal included in the second signal is removed using the correlation; A wireless communication device that performs wireless communication using the full-band duplexer; And a mobile communication terminal for receiving the transmission signal from the radio communication apparatus and transmitting the reception signal for the transmission signal in a time band different from the time band in which the transmission signal is received according to the radio communication apparatus and a predetermined scheduler, And a wireless communication system for a full-band duplexer.

According to another aspect of the present invention, there is provided an apparatus comprising: a directional coupler coupling a transmission signal; A transmission A / D converter for receiving the coupled signal and outputting a first signal obtained by converting the coupled signal into a digital signal; A reception A / D converter for outputting a second signal obtained by converting a reception signal into a digital signal; And a mobile communication terminal that communicates with the antenna, and estimates a channel between the first signal and the second signal by applying a coefficient that minimizes a value obtained by squaring the difference between the first signal and the second signal after predistorting the first signal, And a digital processing unit for controlling the output of the compensated first signal and the second signal so that the target received signal is output to the estimated channel.

According to another aspect of the present invention, there is provided a digital signal processing method for converting a transmission signal into a first signal, which is a digital signal after coupling the transmission signal, converting the reception signal into a second signal, which is a digital signal, A first signal is corrected by applying a coefficient obtained by minimizing a value obtained by squaring the difference between the second signal and the first signal, and the corrected first signal is combined with the second signal, A full-band duplexer for outputting A wireless communication device that performs wireless communication using the full-band duplexer; And a mobile communication terminal for receiving the transmission signal from the radio communication apparatus and transmitting the reception signal for the transmission signal in a time band different from the time band in which the transmission signal is received according to the radio communication apparatus and a predetermined scheduler, And a wireless communication system for a full-band duplexer.

As described above, according to the present invention, since a noise due to a transmission signal and a transmission signal generated in a reception band is eliminated, a separate protection band is not required, and no need to use frequency division or time division. Thereby, the efficiency of radio resources can be greatly increased.

In addition, according to the present invention, a transmission signal is coupled and utilized for removing noise from a received signal. Therefore, it is possible to effectively remove interference due to a transmission signal, to improve efficiency of frequency use, and to improve service quality of a communication carrier It is expected to be possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the 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.

3 is a diagram illustrating an example of using a frequency band according to the present invention. The full-band duplexer of the present invention can use the same frequency band as a transmission band and a reception band by eliminating interference caused by a transmission signal and a transmission signal from a reception signal .

To this end, the full-band duplexer of the present invention couples a transmission signal using a directional coupler, removes a transmission signal and noise caused by the reception signal by using the coupled signal, Techniques.

4 is a configuration diagram of an all-band duplexer according to an embodiment of the present invention.

The full-band duplexer 100 includes a high-power amplifier 111, a transmission filter 112, a directional coupler 113, and a high-power amplifier 111. The high-power amplifier 111 has a structure for processing a transmission signal input from a transmitting terminal of a wireless communication apparatus such as a base station or a repeater. A low noise amplifier 122, a receiving A / D converter 123, a transmitting A / D converter 124, and a transmitting / receiving circuit 122 for processing a signal received wirelessly and inputting the signal to a receiving end. And a digital processing unit 125.

The high power amplifier 111 amplifies the transmission signal and inputs the amplified transmission signal to the transmission filter 112. The transmission filter 112 removes the transmission frequency band from the amplified signal and inputs the amplified signal to the directional coupler 113.

The directional coupler 113 couples the signal input through the transmission filter 112 and inputs the signal to the transmission A / D converter 124, and wirelessly transmits the signal through the antenna.

Here, the antenna used in the full-band duplexer 100 according to an embodiment of the present invention shown in FIG. 4 is a transmission / reception separation type antenna having a high transmission / reception isolation degree.

For example, the full-band duplexer 100 can maximize the performance of removing the interference signal included in the second signal in the digital processing unit 125 by using a transmission / reception separation type antenna having a high transmission / reception isolation degree rather than a general analog antenna It is.

The low noise amplifier 122 amplifies the output signal of the reception filter 121 and outputs the amplified signal to the reception A / D converter 123 .

The transmission A / D converter 124 receives the signal coupled by the directional coupler 113, converts the signal into a digital signal, and outputs the first signal to the digital processing unit 125. The A / 123 inputs a second signal obtained by converting the reception signal output through the reception filter 121 into a digital signal to the digital processing unit 125. [

The digital processing unit 125 receives a first signal output from the transmission A / D converter 124 and a second signal output from the reception A / D converter 123, And removes the transmission signal (first signal) and the interference signal therefrom from the reception signal. As a digital filtering technique, there are a method of utilizing the correlation between two signals and a filtering method, which will be described with reference to FIG. 5 to FIG.

In addition, the full-band duplexer 100 sets a frequency reuse factor (FRF) to a value other than 1.

In general, when the same frequency is used for each sector in the base station, the frequency reuse factor (FRF) = 1 can be set. However, the full-band duplexer 100 of the present invention uses a transmission / reception separation type antenna with high transmission / , A frequency other than the same frequency is used between the sectors, so that the frequency reuse factor FRF is set to a value other than 1.

For example, when the same frequency is used for each sector in a base station, an interference signal due to the same frequency may occur. Therefore, a frequency reuse factor (FRF) may be set to a value other than 1 and a transmission / reception separation antenna having a high transmission / It is possible to prevent an interference signal from being generated.

In addition, the digital processing unit 125 performs a function of extracting a channel between a mobile communication terminal communicating with a transmission / reception separation antenna and outputting a target reception signal using the extracted channel.

That is, a mobile communication terminal communicating with the full-band duplexer 100 of the present invention extracts a channel, which is a technique used in a MIMO (Multiple Input Multiple Output) system, and communicates with a mobile communication terminal using an extracted channel, The lager 100 can reduce the number of antennas required for communication.

5 is a diagram of a first embodiment of a digital processing unit, which relates to a digital filtering technique that utilizes signal correlation.

The digital processing unit 125-1 of FIG. 5 is implemented by an anti-phase combiner, and the anti-phase combiner receives the received signal (received signal + noise) and the noise signal (transmitted signal of the present invention) And outputs only the removed target received signal. That is, the anti-phase combiner uses the correlation between the first signal output from the transmission A / D converter 124 and the second signal output from the reception A / D converter 123, Phase signal of the included interference signal (first signal), extracts the target received signal by combining the generated anti-phase signal and the second signal, and provides the received signal to the receiving end so as to suppress the interference due to the transmitted signal.

In addition, the full-band duplexer 100 pre-distorts the first signal using the extracted channel and then outputs a target reception signal from which the interference signal included in the second signal is removed by using the correlation of the second signal As shown in FIG.

Here, the pre-distortion is a technique used in DPD (Digital Pre-Distortion) Amp or the like, and is used to maximize the performance of removing the interference signal included in the second signal in the digital processing unit 125.

In addition, the full-band duplexer 100 of the present invention pre-modulates the terminal signals included in the first signal and the second signal to have mutual orthogonality, and then uses the correlation between the first signal and the second signal, And outputs a target reception signal from which the interference signal included in the received signal is removed. Here, the terminal signal means a signal transmitted from the mobile communication terminal to the base station.

Next, Fig. 6 is a diagram showing a second embodiment of the digital processing section, and Fig. 7 is a diagram showing a third embodiment of the digital processing section, in which an embodiment using a filtering technique is shown.

The digital processing unit 125-2 of FIG. 6 is implemented using a Wiener filter. The Wiener Filter is a filter that transforms the input as closely as possible to the desired output. The meaning of 'as close as possible' means that the sum of the squares of the differences of the two input signals is the minimum, It is also called a least squares filter.

That is, the Wiener filter is an algorithm that minimizes the square of the difference between the noise component and the signal when the signal and the noise coexist at the input end. The Wiener filter is mainly applied to a time invariant system. In the present invention, And a second signal output from the receiving A / D converter, and applying a coefficient (W) obtained by minimizing a value obtained by squaring the difference between the second signal and the first signal to a first And combines the corrected first signal and the second signal to filter the first signal (noise) output from the transmission A / D converter 124. [

Therefore, the digital processing unit 125-2 of the second embodiment outputs the signal filtered by the Wiener filter, that is, the corrected first signal and the second signal outputted from the receiving A / D converter 123 + Noise), thereby outputting a target signal (target received signal) from which noise is removed as much as possible.

On the other hand, since the present invention is applied to a wireless communication device, the antenna is installed outdoors or the like, thereby causing a Doppler effect due to a moving object in the vicinity. Therefore, a digital processing unit can be implemented using an adaptive filter suitable for time variation rather than a Wiener filter, as shown in FIG.

The digital processing unit 125-3 of FIG. 7 is implemented by an adaptive filter, so that the adaptive filter minimizes the mean square error between the corrected first signal and the second signal output from the receiving A / D converter 123 (Noise) output from the transmission A / D converter 124 using the coefficient value W to be used in the case of the Wiener filter, and in the case of the Wiener filter, the coefficient value While the adaptive filter performs adaptive filtering on the time variation by determining the coefficient value in signal sample units.

6, the digital processing unit 125-3 of the present embodiment also receives a signal filtered by the adaptive filter and a second signal (target signal + noise (noise)) output from the receiving A / D converter 123 ) To provide a target signal (target received signal) from which noise has been removed to the receiving end as much as possible.

8 is an exemplary diagram for explaining a method in which a full-band duplexer processes a signal in cooperation with a mobile communication terminal.

In addition, when it is assumed that the full-band duplexer 100 of the present invention is included in a wireless communication apparatus such as a base station and operates, the wireless communication apparatus uses a full-band duplexer 100 to transmit a transmission signal To the mobile communication terminal during the entire time band.

8 (B) to 8 (E), the wireless communication apparatus sets a scheduler for a signal to be transmitted to and received from the mobile communication terminal, and outputs a reception signal for the transmission signal to a time band different from the time band in which the transmission signal is received So that the mobile communication terminal does not have any processing for interference cancellation.

That is, when the mobile communication terminal receives the transmission signal from the wireless communication device, the mobile communication terminal transmits the reception signal for the transmission signal in a time band different from the time band in which the transmission signal is received according to the wireless communication apparatus and the predetermined scheduler, The transmission signal and the reception signal are not generated in the frequency band, so that the interference phenomenon occurring in the mobile communication terminal can be reduced.

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 intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

As described above, the present invention is applied to a full-band duplexer field in which a full-band signal can be utilized without separating a transmission / reception band by outputting a signal in which an interference signal due to a transmission signal is removed from a reception signal by applying a digital filtering technique, Is a very useful invention that does not require the guard band of the frequency band and does not require frequency division or time division, and can be used in the full band.

1 is a diagram illustrating an example of frequency band use in a conventional FDD system,

2 is a diagram illustrating an example of frequency band use in an FDD system utilizing a conventional PIM eliminator,

3 is a diagram illustrating an example of using the frequency band of the present invention,

4 is a configuration diagram of a full-band duplexer according to an embodiment of the present invention;

5 shows a first embodiment of a digital processing unit,

6 shows a second embodiment of a digital processing unit,

7 shows a third embodiment of the digital processing unit,

8 is an exemplary diagram for explaining a method in which a full-band duplexer processes a signal in cooperation with a mobile communication terminal.

Description of the Related Art

100: full-band duplexer 111: high-power amplifier

112: Transmission filter 113: Directional coupler

121: Receive filter 122: Low noise amplifier

123: receiving A / D converter 124: transmitting A / D converter

125: Digital Processing Unit

Claims (10)

A directional coupler coupling the transmission signal; A transmission A / D converter for receiving the coupled signal and outputting a first signal obtained by converting the coupled signal into a digital signal; A reception A / D converter for outputting a second signal obtained by converting a reception signal into a digital signal; And The method includes extracting a channel with a terminal that communicates using a transmit / receive detachable antenna, pre-distorting the first signal using the channel, and using the correlation with the second signal, And a digital processing unit for controlling the frequency reuse factor (FRF) to be a value other than 1 to control the output of only the target received signal from which the interference signal is removed to the channel, Wherein the duplexer comprises a duplexer. delete delete The method according to claim 1, The full-band duplexer includes: Modulated to have mutual orthogonality between the first signal and the terminal signal included in the second signal. delete A directional coupler coupling the transmission signal; A transmission A / D converter for receiving the coupled signal and outputting a first signal obtained by converting the coupled signal into a digital signal; A reception A / D converter for outputting a second signal obtained by converting a reception signal into a digital signal; And Extracting a channel with a terminal communicating with the transmitting / receiving detachable antenna, pre-distorting the first signal using the channel, and applying a coefficient for minimizing a value obtained by squaring the difference between the first signal and the second signal A digital processing unit which controls the first signal to be corrected and outputs a target reception signal obtained by combining the corrected first signal and the second signal to the channel and sets the frequency reuse ratio to a value other than 1, Wherein the duplexer comprises a duplexer. delete delete The method according to claim 6, The full-band duplexer includes: Wherein the first signal and the second signal are pre-modulated to have mutual orthogonality between the first signal and the terminal signal included in the second signal. delete

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