KR102023433B1 - intermodulation canceling device and its method - Google Patents

Abstract

The present invention relates to an apparatus for removing intermodulation signals generated in a reception band by a transmission signal from a reception signal and removing interference of the reception band by the transmission signal to improve the reception quality of the reception signal, and to a method thereof. The apparatus for removing intermodulation includes a transmission unit, a reception unit for removing the intermodulation signals in which the output of the transmission unit is generated in the reception band from the reception signal, and a coupling unit for coupling the transmission unit and the reception unit.

Description

Intermodulation canceling device and its method

The present invention relates to a device and a method for intermodulation cancellation, and in particular, to remove the effect of the intermodulation signal of the transmission signal on the received signal. That is, the present invention relates to an apparatus and method for removing intermodulation that can predict a modulated signal of a received signal band from a transmitted signal and remove the received signal from the received signal.

For the development of mobile communication, increasing service capacity and minimizing installation costs are becoming important issues. In order to increase the service and minimize the installation cost, the reality is that the transmission power is increased or the broadband power is used to increase the integrated power.

At this time, due to power overload, intermodulation occurs in passive elements such as antennas, couplers, connectors, and cables.

Passive Intermodulation Distortion (PIMD), which is interference, generates unwanted parasitic signals by interfering with each other in frequencies in a transmission signal. Unlike the Active Intermodulation Distortion (AIMD) generated in active devices, It occurs on the RF path, and the level is also very difficult to predict, and efforts have been made to eliminate such intermodulated signals.

For example, Korean Patent Laid-Open Publication No. 10-2012-0021584 proposes a method for removing a passive intermodulation signal by soldering using a bonding material at a connection point between a connector and a feeder of a router.

However, even in this case, there is a problem that can not eliminate the effect on the received signal.

Republic of Korea Patent Publication No. 10-2012-0021584 (2012.03.02.)

SUMMARY OF THE INVENTION An object of the present invention is to provide an intermodulation cancellation apparatus and method for removing an intermodulation signal generated in a reception band by a transmission signal from a reception signal.

Another object of the present invention is to provide an apparatus and method for removing intermodulation, which improves reception quality of a reception signal by removing interference of a reception band caused by a transmission signal.

The apparatus for removing intermodulation according to the present invention may include a transmitter, a receiver configured to remove an intermodulated signal in which an output of the transmitter is generated in a reception band from a received signal, and a coupling unit coupled to the transmitter and the receiver.

Here, the receiver may remove the intermodulated signal generated by the transmitter.

Also, the receiver may remove the intermodulation signal generated at the combiner with respect to the output of the transmitter.

Here, the coupling unit may be configured of at least one of a combiner, a filter, a switch, an antenna, a connector, and a cable.

Also, the receiver may include an intermodulation generator for generating an intermodulation signal and an intermodulation canceller for canceling the intermodulation signal.

Here, the intermodulation generator may include a transmission power detection module for detecting the transmission power of the transmitter and a reception band intermodulation generation module for generating the intermodulation signal for the reception band.

In addition, the intermodulation generator includes a transmission band intermodulation detection module for receiving the transmission of the transmitter and the output of the combiner to detect the intermodulation signal of the transmission band, and a reception band intermodulation generation module for generating the intermodulation signal for the reception band. can do.

Here, the intermodulation generator may generate the intermodulation signal when the transmission power is greater than or equal to a predetermined value.

In addition, the intermodulation generator performs the intermodulation generation by under sampling, and can eliminate the interference (aliasing) of the under sampling.

Here, the intermodulation canceller may include a reception band intermodulation cancellation module for removing a reception band intermodulation signal from a combiner's reception signal and a low noise amplification module for performing low noise amplification on an output of the reception band intermodulation cancellation module. .

In addition, the intermodulation canceller may include a low noise amplification module that performs low noise amplification from the received signal of the combiner, and a reception band intermodulation cancellation module that removes the intermodulation signal of the reception band from the output of the low noise amplification module.

Here, the intermodulation canceller can remove the intermodulation signal asynchronously using an equalizer.

In addition, the intermodulation canceller may remove the intermodulation signal when the transmission power is greater than or equal to a set value.

According to another exemplary embodiment of the present invention, a method of canceling intermodulation may include a transmitting step, a combining step of combining a transmitter and a receiver, and a receiving step of removing an intermodulation signal generated at an output band of a transmitter from a receiver.

Here, the receiving step may include an intermodulation generating step of generating the intermodulation signal and an intermodulation removing step of removing the intermodulation signal.

The apparatus and method for canceling intermodulation according to the present invention has the advantage of removing the intermodulation signal generated in the reception band by the transmission signal from the received signal.

In addition, the apparatus and method for removing intermodulation according to the present invention has an advantage of improving reception quality of a reception signal by removing interference of a reception band caused by a transmission signal.

1 is a block diagram showing an apparatus for canceling intermodulation according to an embodiment of the present invention.
FIG. 2 is a waveform illustrating input of a receiver for a case where there is no interference signal in the receiver of FIG. 1.
3 is a waveform illustrating an input of a receiver for an interference signal in the receiver of FIG. 1.
4 is a configuration diagram illustrating in detail the receiver of FIG. 1.
5 is a configuration diagram illustrating in detail the intermodulation generator of FIG. 4.
6 is another configuration diagram illustrating in detail the intermodulation generator of FIG. 4.
FIG. 7 is a detailed block diagram illustrating the intermodulation canceller of FIG. 4.
8 is another configuration diagram illustrating in detail the intermodulation canceller of FIG. 4.
9 is a flowchart illustrating a method of canceling intermodulation according to an embodiment of the present invention.
10 is a flowchart illustrating the receiving step of FIG. 9 in detail.

Specific embodiments of the present invention will be described with reference to the accompanying drawings.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. It is not intended to limit the invention to the specific embodiments, it can be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, an apparatus and a method for canceling intermodulation according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating an apparatus for canceling intermodulation according to an embodiment of the present invention, and FIGS. 2 to 8 are detailed waveforms and block diagrams for explaining FIG. 1 in detail.

Hereinafter, an apparatus for canceling intermodulation according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

First, referring to FIG. 1, an apparatus for removing intermodulation according to an embodiment of the present invention includes a transmitter 300 and a receiver 300 for removing an intermodulated signal generated in a reception band of an output of the transmitter 100 from a received signal. , And a combiner 200 for coupling the transmitter 100 and the receiver 300.

Here, the receiver 300 may remove the intermodulation signal generated by the transmitter 100.

In addition, the receiver 300 may remove the intermodulation signal generated by the combiner 200 with respect to the output of the transmitter 100.

Here, the coupling unit 200 may be composed of a combiner, a filter, a switch, an antenna, a connector, a cable, and the like.

The intermodulation may include active intermodulation occurring in the active element inside the transmitter 100 and passive intermodulation occurring in the passive element inside the combiner 200.

Interference affecting the received signal may include active intermodulation and passive intermodulation.

In this case, intermodulation is generated by intermodulation between frequencies in a transmission signal and can be classified into odd orders and even orders. Even orders affect N times the transmission frequency, but odd orders affect the transmission frequency. There is a characteristic.

In addition, in the vicinity of the transmission frequency, low order intermodulation, such as 3rd and 5th order, is affected. However, when the distance from the transmission frequency is reduced, high order intermodulation may be affected.

The intermodulation becomes larger as the size of the transmission signal increases, and may affect the reception signal band.

2 to 3 are waveforms showing the influence of interference on the reception signal band according to the transmission signal size.

FIG. 2 is a waveform illustrating input of the receiver 300 when there is no interference signal in the receiver 300 of FIG. 1. As shown in FIG. 2, when the output of the transmission signal 400 is low, the size of the intermodulation signal is small due to the transmission signal 400, and thus does not affect the reception signal 500.

On the other hand, when the output of the transmission signal 400 is high, since the size of the intermodulation signal by the transmission signal 400 is large, it may affect the reception signal 500.

3 is a waveform illustrating an input of a receiver 300 when there is an interference signal in the receiver 300 of FIG. 1. As can be seen in FIG. 3, when the output of the transmission signal 600 is high, intermodulation may occur in the transmitter 100 or the combiner 200 and may affect the received signal 500. In this case, since the reception signal 500 is the case where the reception signal 800 is added after the intermodulation signal 700 and the intermodulation removal, it can be seen that the interference effect is large.

In this case, the intermodulation signal 700 may be active intermodulation generated by the transmitter 100, passive intermodulation generated by the combiner 200, or may include both active intermodulation and passive intermodulation.

Therefore, if the intermodulation signal 700 is not removed from the reception signal 500, the interference effect is large, and thus the reception performance may be improved by removing the intermodulation signal 700 and extracting the reception signal 800 after the intermodulation removal. .

4 is a diagram illustrating in detail the receiver 300 of FIG. 1.

As shown in FIG. 4, the receiver 300 may include an intermodulation generator 310 generating an intermodulation signal and an intermodulation eliminator 320 removing an intermodulation signal.

Here, the intermodulation generator 310 may generate the intermodulation signal when the transmission power is greater than or equal to a predetermined value.

In addition, the intermodulation generator 310 may perform the intermodulation generation by under sampling, and may remove the interference (aliasing) of the under sampling.

Here, the intermodulation canceller 320 may remove the intermodulation signal asynchronously using an equalizer.

In addition, the intermodulation canceller 320 may remove the intermodulation signal when the transmission power is greater than or equal to a predetermined value.

Here, the intermodulation generator 310 may generate an intermodulation signal that affects a reception band from the transmission signal 600 through an intermodulation model.

At this time, if the frequency difference between the transmission band and the reception band is large, the order of the intermodulation model is increased, and high-speed signal processing is required to process the signal.

Therefore, it can be performed with under sampling smaller than twice the bandwidth of the transmission frequency or the transmission signal, whereby interference (aliasing) may occur due to overlapping sampling.

That is, by removing the interference (aliasing) according to the intermodulation order in the intermodulation model to generate the intermodulation signal in the reception band, signal processing can be performed at a low speed.

On the other hand, when the magnitude of the transmission power is small, there is no interference due to the intermodulation, and thus the interference signal may not be generated. In this case, the noise generated by the intermodulation generator affects the intermodulation canceller 320. There is an advantage that does not reach.

FIG. 5 is a detailed block diagram illustrating the intermodulation generator 310 of FIG. 4.

As can be seen in FIG. 5, the intermodulation generator 310 includes a transmission power detection module 311 for detecting the transmission power of the transmitter 100 and a reception band intermodulation generation module for generating the intermodulation signal for the reception band. 312.

Here, the transmission power detection module 311 may detect the transmission power to perform the operation of the reception band intermodulation generation module 312, and only when the transmission power is greater than or equal to a set value, the transmission band detection module 312 may perform the intermodulation signal. May occur.

Meanwhile, the reception band intermodulation generation module 312 may use an intermodulation model to generate intermodulation in the reception band, and may generate N orders of intermodulation signals using the Taylor series or Volterra series. .

In addition, a covariance operation may be performed on the output of the Taylor series or Volterra series so that the N-order intermodulation signals are orthogonal to each other.

6 is another configuration diagram illustrating in detail the intermodulation generator 310 of FIG. 4.

As shown in FIG. 6, the intermodulation generator 310 receives a feedback of the transmission of the transmitter 100 and the output of the combiner 200 and detects the intermodulation signal of the transmission band. And a reception band intermodulation generating module 314 for generating an intermodulation signal for the reception band.

Here, the transmission band intermodulation detection module 313 is a module configured to determine the magnitude of the intermodulation signal generated by the transmitter 100 in the actual combiner 200.

In this case, the transmission band intermodulation detection module 313 may extract the difference between the signal in the transmission band received by the combiner 200 and the transmission signal of the transmitter 100 to extract the intermodulation signal in the transmission band.

In addition, the intermodulation model can be compensated for from the characteristics of the intermodulation signal in the transmission signal band.

That is, by compensating the magnitude, phase, and delay with respect to the order of the Taylor series or the Volterra series, the model accuracy of the intermodulation characteristics in the transmitter 100 and the combiner 200 may be increased.

On the other hand, in the reception band intermodulation generation module 314, like the reception band intermodulation generation module 312, an intermodulation model can be used to generate intermodulation in the reception band. It is possible to generate an order-of-order intermodulation signal.

In addition, a covariance operation may be performed on the output of the Taylor series or Volterra series so that the N-order intermodulation signals are orthogonal to each other.

FIG. 7 is a detailed block diagram illustrating the intermodulation canceller 320 of FIG. 4.

As can be seen in FIG. 7, the intermodulation canceller 320 includes a reception band intermodulation cancellation module 322 and a reception band intermodulation cancellation module for removing the reception band intermodulation signal from the reception signal of the combiner 200. A low noise amplification module 321 that performs low noise amplification on the output of 322.

Here, the reception band intermodulation cancellation module 322 performs the low noise amplification module 321 before the low noise amplification module 321 to lower the size of the intermodulation received by the low noise amplification module 321, thereby providing the input of the IIMD (Input) of the low noise amplification module 321. Intermodulation Distortion) has the effect of improving performance.

Meanwhile, the reception band intermodulation cancellation module 322 may simply remove the output of the intermodulation generator 310 from the output of the combiner 200 by subtraction, and include the output of the reception band intermodulation cancellation module 322. The output component of the intermodulation generator 310 may be configured to be the minimum.

In addition, a delay may occur between the signal of the reception band intermodulation cancellation module 322 and the output of the combiner 200. The delay may be fixed in the system to synchronize and may be implemented asynchronously including an equalizer. have.

In this case, when implemented using an equalizer, synchronization between the output of the intermodulation generator 310 and the output of the coupling unit 200 is not required, and the intermodulation signal is removed even if the configuration of the coupling unit 200 changes with time. There is an advantage to this.

8 is another configuration diagram illustrating in detail the intermodulation canceller 320 of FIG. 4.

As can be seen in FIG. 8, the intermodulation canceller 320 is coupled to the output of the low noise amplification module 324 and the low noise amplification module 324 to perform low noise amplification from the received signal of the combiner 200. A reception band intermodulation cancellation module 323 for canceling the intermodulation signal may be included.

Here, the low noise amplification module 324 has an advantage that can be removed before the reception band intermodulation cancellation module 323 to effectively remove the intermodulation signal for a low magnitude.

Meanwhile, the reception band intermodulation cancellation module 322 may simply remove the output of the intermodulation generator 310 from the output of the combiner 200 by subtracting the interband with respect to the output of the reception band intermodulation cancellation module 322. Feedback may be implemented such that the output of the modulation generator 310 is minimal.

In addition, a delay may occur between the signal of the reception band intermodulation cancellation module 322 and the output of the combiner 200. The delay may be fixed in the system to synchronize and may be implemented asynchronously including an equalizer. have.

In this case, when implemented using an equalizer, synchronization between the output of the intermodulation generator 310 and the output of the coupling unit 200 is not required, and the intermodulation signal is removed even if the configuration of the coupling unit 200 changes with time. There is an advantage to this.

FIG. 9 is a flowchart illustrating a method of canceling intermodulation according to an embodiment of the present invention, and FIG. 10 is a detailed flowchart illustrating FIG. 9 in detail.

Hereinafter, a method of canceling intermodulation according to another embodiment of the present invention will be described with reference to FIGS. 9 to 10.

First, referring to FIG. 9, in the method of canceling intermodulation according to another exemplary embodiment of the present invention, at step S100, at step S200, at step S200, and at the receiver 300, the transmitter 100 is coupled to the receiver 300. The output of the transmitter 100 is performed to remove the intermodulation signal generated in the reception band (S300).

The transmission signal generated in the transmission step S100 may affect the reception signal band according to the size of the signal.

As described above, the intermodulation may include active intermodulation occurring in the active element inside the transmitter 100 and passive intermodulation occurring in the passive element inside the combiner 200. Is omitted.

FIG. 10 is a flowchart illustrating the receiving step S300 of FIG. 9 in detail.

As can be seen in Figure 10, the receiving step (S300) consists of the step of generating the intermodulation signal (S310) and the step of removing the intermodulation signal (S320).

That is, the intermodulation signal of the received signal band may be generated based on the transmission signal in the intermodulation generation step (S310). In this case, the signal processing may be performed at a low speed by removing the interference (aliasing) due to the under sampling. This can occur simply by using a Taylor series or Volterra series when intermodulation occurs.

Meanwhile, in the intermodulation removing step S320, the intermodulation signal generated in the intermodulation generating step S310 may be removed from the received signal, and when implemented using an equalizer, the output and coupling unit 200 of the intermodulation generator 310 may be removed. There is no need for synchronization of the output of), and even if the configuration of the coupling unit 200 changes with time, there is an advantage of removing the intermodulation signal.

As described above, the apparatus and method for canceling intermodulation according to the present invention has the advantage of removing the intermodulation signal generated in the reception band by the transmission signal from the reception signal. There is an advantage of improving the reception quality.

What has been described above includes examples of one or more embodiments. Of course, rather than describing all possible combinations of components or methods for the purpose of describing the above-described embodiments, those skilled in the art may recognize that many further combinations and substitutions of the various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.

Claims (15)

A transmitter;
A receiver for removing an intermodulation signal generated in a reception band from an output of the transmitter from a received signal; And
And a combiner for coupling the transmitter and the receiver.
The receiving unit,
An intermodulation generator for generating an intermodulation signal; And
And an intermodulation canceller for removing the intermodulation signal,
The intermodulation generator performs intermodulation generation with undersampling less than twice the transmission frequency or bandwidth of the transmission signal, eliminates undersampling interference (aliasing),
The intermodulation generator,
A transmission band intermodulation detection module configured to detect the intermodulation signal of a transmission band by receiving feedback from the transmission of the transmitter and the output of the combiner; And
A reception band intermodulation generating module for generating the intermodulation signal for a reception band through an intermodulation model;
Generating an intermodulation signal in a reception band by removing interference (aliasing) according to an intermodulation order in the intermodulation model;
The interference (aliasing) according to the intermodulation order is the intermodulation signal which acts as interference (aliasing) on the reception band according to the intermodulation order of the transmission signal. The method of claim 1,
And the receiver removes the intermodulation signal generated by the transmitter. The method of claim 1,
And the receiver removes the intermodulation signal generated in the coupling unit with respect to the output of the transmitter. The method of claim 1,
The coupling unit is at least one of a combiner, a filter, a switch, an antenna, a connector, and a cable. delete The method of claim 1,
The intermodulation generator,
A transmission power detection module for detecting transmission power of the transmission unit; And
And a reception band intermodulation generating module generating the intermodulation signal for the reception band. delete The method of claim 1,
And the intermodulation generator generates the intermodulation signal when the transmission power is greater than or equal to a set value. delete The method of claim 1,
The intermodulation canceller may include: a reception band intermodulation cancellation module for removing the intermodulation signal of a reception band from a reception signal of the combiner; And
And a low noise amplification module for performing low noise amplification on an output of the reception band intermodulation cancellation module. The method of claim 1,
The intermodulation canceller may include: a low noise amplification module configured to perform low noise amplification from the received signal of the combiner; And
And a reception band intermodulation cancellation module for removing the intermodulation signal in a reception band with respect to an output of the low noise amplification module. The method of claim 1,
And wherein said intermodulation canceller cancels said intermodulation signal asynchronously using an equalizer. The method of claim 1,
And wherein the intermodulation canceller removes the intermodulation signal when the transmit power is greater than or equal to a set value. Transmitting step;
Combining the transmitter and the receiver in a combiner; And
And a receiving step of removing, by the receiving unit, the intermodulated signal generated in the reception band by the output of the transmitting unit.
The receiving step,
An intermodulation generating step of generating an intermodulation signal; And
And a cross modulation cancellation step of removing the intermodulation signal.
In the intermodulation generation step, the intermodulation generation is performed with under sampling smaller than twice the transmission frequency or bandwidth of the transmission signal, and eliminates interference (aliasing) of under sampling,
The intermodulation generating step,
Receiving the feedback of the transmission of the transmitter and the output of the combiner to detect the intermodulated signal of a transmission band,
Generating the intermodulated signal for a reception band through an intermodulation model,
Generating an intermodulation signal in a reception band by removing interference (aliasing) according to an intermodulation order in the intermodulation model;
The interference (aliasing) according to the intermodulation order is the intermodulation signal which acts as interference (aliasing) on the reception band according to the intermodulation order of the transmission signal. delete

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