KR20230060806A - Apparatus and method for rf interference signal reduction for receiver - Google Patents

Abstract

In accordance with the present invention, an RF inference signal reduction apparatus for a receiver includes: an interference signal reducer antenna outputting a reference signal; a first bandpass filter receiving the reference signal from the interference signal reducer antenna and restricting a reception band; a simulated signal shaping module simulating a signal having the same magnitude and phase as the interference signal based on the signal received from the first bandpass filter; a fourth power combiner sampling a part of the output of the simulated signal shaping module and forwarding the part to a control part and forwarding the rest of the signals to a first power combiner; the first power combiner combining the simulated signal with a target interference receiver to eliminate an interfering signal existing in the reception path; a second bandpass filter receiving the signal from the receiver antenna; a second variable delay line receiving the signal from the second bandpass filter and adjusting a delay time of the received signal; a third power combiner receiving the signals from the second variable delay line and forwarding some of the signals to the control part and forwarding the rest of the signals to the first power combiner; a second power combiner sampling a part of the output of the first power combiner and forwarding the part to the control part and forwarding the remaining output signals of the first power combiner to the receiving part; and the control part detecting the degree to which the interfering signal is eliminated, and controlling the simulated signal shaping module and the second variable delay line depending on the degree to which the interfering signal is eliminated. Therefore, the present invention is capable of increasing frequency use efficiency.

Description

Apparatus and method for reducing RF interference signal for receiver {APPARATUS AND METHOD FOR RF INTERFERENCE SIGNAL REDUCTION FOR RECEIVER}

The present invention is an invention for reducing interference between wireless transceivers operating in the same frequency band or an adjacent frequency band, and more specifically, for a receiver capable of reducing an RF interference signal affecting reception performance in a wireless environment. It relates to an apparatus and method for reducing RF interference signals.

Although different services are provided for efficient use of frequency resources, the need for a technology that can jointly use the same frequency band or use adjacent bands is increasing day by day. For the development of wireless transceivers using the same frequency band, many studies on full-duplex wireless communication systems have recently been conducted. However, in order to implement a full-duplex wireless communication system, the interference signal generated by its own transmitter must be removed, and the size range of the interference signal to be removed is quite wide, so in the RF (Radio Frequency) and BB (Base Band) areas Each self-interference signal must be removed. Also, in a full-duplex wireless communication system, interference signals from other transmitters providing the same service must be removed to establish a communication link. As such, there are currently technical limitations in actually implementing sophisticated techniques for canceling self-interference signals and interference signals caused by other transmitters, and due to this, full-duplex wireless communication systems have not reached the stage of providing current services. Interference signal cancellation technologies for proper operation of a full-duplex wireless communication system are mostly focused on technologies for eliminating self-interference signals generated by the system itself, and technologies for eliminating interference signals generated by other transmitters are being sought. It is difficult to see.

An object of the present invention to solve the above problems is to suppress interference generated between wireless communication systems using the same frequency or an adjacent frequency band, thereby reducing the physical separation distance in space and making the service more smooth. It is possible to provide, and ultimately to provide an RF interference signal reduction device for a receiver capable of increasing frequency use efficiency.

Another object of the present invention to solve the above problems is to suppress interference generated between wireless communication systems using the same frequency or adjacent frequency bands, thereby reducing the physical separation distance in space and providing services more smoothly. The object of the present invention is to provide a method for reducing RF interference signals for a receiver that can provide a high efficiency and ultimately increase frequency use efficiency.

An RF interference signal reduction device for a receiver according to an embodiment of the present invention for achieving the above object is an interference signal reducer antenna that outputs a reference signal, a reference signal is applied from the interference signal reducer antenna and the reception band is limited A first band-pass filter, a simulated signal shaping module that simulates a signal having the same magnitude and phase as the interference signal based on the signal applied from the first band-pass filter, and a part of the output of the simulated signal shaping module is sampled and sent to the control unit. The fourth power combiner transfers the remaining signal to the first power combiner, the first power combiner combines the simulated signal with the interference receiving device to remove the interference signal existing in the receiving path, and applies the signal from the receiver antenna A receiving second band pass filter, a second variable delay line for receiving a signal from the second band pass filter and adjusting a delay time of the received signal, receiving a signal from the second variable delay line and transferring some signals to the controller and a third power combiner that transmits the remaining signal to the first power combiner, a portion of the output of the first power combiner that is sampled and transmitted to the control unit, and the remaining output signal of the first power combiner to the receiver A second power combiner that transmits the sample, and a control unit that detects the degree to which the interference signal has been removed and controls the simulated signal shaping module and the second variable delay line according to the degree to which the interference signal has been removed.

The RF interference signal reduction apparatus and method for a receiver of the present invention increases frequency utilization efficiency by reducing the effect of interference between wireless communication systems using the same frequency or adjacent frequency bands.

In addition, the apparatus and method for reducing RF interference signals for a receiver can reduce the spatial separation distance for mitigating existing interference when using the same frequency or adjacent frequency bands, so that desired services can be provided more smoothly.

In addition, since the apparatus and method for reducing RF interference signals for receivers provide an interference margin to the system even when the existing spatial distance for mitigating interference is kept the same, there is an effect of guaranteeing the stability of the communication link. .

1 is a schematic diagram showing that interference between systems occurs.
2 is a block diagram of an RF interference signal reducer according to an embodiment of the present invention.
3 is a block diagram of a receiver to which a conventional RF interference signal reducer is applied.
4 is a diagram showing an example of an RF interference signal reducer flowing into a receiver according to an embodiment of the present invention.
5 is a diagram showing an example of an RF interference signal reducer flowing into a receiver according to another embodiment of the present invention.
6 is a diagram showing an example of an RF interference signal reducer flowing into a receiver according to another embodiment of the present invention.
7A is a graph showing the performance of the interference signal reducer when the RF interference signal reducer is applied to the front end of the original receiver.
7B is a graph showing the performance of the RF interference signal reducer when the RF interference signal reducer is applied to the rear end of the band pass filter (center frequency F1) of the original receiver.
7C is a graph showing the performance of the RF interference signal reducer in the case where the RF interference signal reducer is applied after the band pass filter (center frequency F2) of the original receiver.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B”.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

1 is a schematic diagram showing that interference between systems occurs.

Referring to FIG. 1 , the non-interference receiver may be a second service receiver receiving a second service transmission signal. The interference-resistant receiver may receive the first service transmission signal as well as the second service transmission signal. Here, the first service transmission signal transmitted by the first service transmitter may be an interference signal to the receiver to be interfered with. Therefore, the receiver to be interfered with may not be able to properly provide the second service due to the interference of the transmission signal of the first service.

2 is a block diagram of a conventional interference signal reducer.

If there is no interference signal, the original transmitter's signal can be applied directly to the original receiver through the original antenna and subtraction circuit.

On the other hand, when there is an interference signal as shown in FIG. 1, the antenna of the original receiver can simultaneously receive the signal of the original transmitter and the signal transmitted from the interference transmitter. In order to cancel or reduce the interference signal of the interference transmitter received by the original receiver, the signal of the interference transmitter may be received by the reference antenna. The replica signal shaping module may generate a signal having the same amplitude and phase as the interference signal received through the original antenna based on the interference signal received through the reference antenna. The simulated signal shaping module may apply a signal having the same magnitude and phase as the interference signal received through the original antenna to a subtraction circuit, and through this, the interference signal received through the original antenna may be removed or reduced.

In other words, the simulated signal shaping module may generate a simulated signal having the same magnitude and phase as the interference signal applied to the original receiver. The simulated signal shaping module may generate the generated simulated signal using a signal (reference signal) applied to a reference antenna. The simulated signal shaping module may apply the simulated signal to a subtraction circuit. The subtraction circuit may remove or reduce an interference signal applied to the original receiver based on the simulated signal.

3 is a block diagram of a receiver to which a conventional interference signal reducer is applied.

Referring to FIG. 3, the existing interference signal reducer 200 includes an interference signal reducer antenna 300, a simulated signal shaping module 400, a first power combiner 500, a second power combiner 502, and A controller 600 may be included.

The interference signal reducer antenna 300 may receive an interference signal. The simulated signal shaping module 400 may shape a signal having the same amplitude and phase as the interference signal received through the receiver antenna 100 based on the interference signal received from the interference signal reducer antenna 300 . The simulated signal shaping module 400 may output a signal having the same amplitude and phase as the interference signal received at the receiver antenna 100 . The output of the simulated signal shaping module 400 can be power-combined with the signal received at the receiver antenna 100 after only the phase is reversed by 180° through the first power combiner 500 . Therefore, the first power combiner 500 can output a signal from which the interference signal has been removed from the signal coming into the receiver antenna 100 .

Here, the first power combiner 500 may provide a function of a subtraction circuit. The first power combiner 500 may be implemented as a 180° hybrid or a transformer. The first power combiner 500 may output a received signal from which an interference signal has been removed. An output signal of the first power combiner 500 may be applied to the second power combiner 502 . The second power combiner 502 may apply some of the output signals of the first power combiner 500 to the controller 600 and transfer the remaining signals to the receiver 700 .

Here, the controller 600 may include a power detector. The power detector may check the interference signal removal or reduction degree of the signal applied to the controller 600 as power. The controller 600 may control the simulated signal shaping module 400 based on the interference signal removal degree of the applied signal.

Here, the second power combiner 502 may be implemented as a coupler that samples the signal of the receiver 700 in order to check the degree of interference signal cancellation.

The controller 600 can check the degree of interference signal cancellation using the power detector, but a more accurate interference signal cancellation degree can be obtained by using the signal to noise ratio (SNR) obtained after baseband signal processing. may be In this case, signal-to-noise ratio information may be applied from the receiver to the controller 600.

Referring to FIG. 3 , the interference signal reducer antenna 300 can receive not only the interference signal but also the signal of the original transmitter. In this case, the performance of the RF interference signal reducer 200 may deteriorate. In order to prevent the performance of the RF interference signal reducer 200 from deteriorating, the interference signal reducer antenna 300 may receive only the interference signal by using an antenna having a performance different from that of the receiver antenna 100.

For example, the interference signal reducer antenna 300 and the receiver antenna 100 may use a satellite antenna and a dipole antenna. Even when the satellite antenna and the dipole antenna operate in the same frequency band, there may be a difference in gain for a signal that can be received. The dipole antenna can hardly receive satellite signals, and the satellite antenna can receive signals received by the dipole antenna as well as satellite signals. Here, the dipole antenna can be used as the interference signal reducer antenna 300, and the satellite antenna can be used as the receiver antenna 100.

4 is a diagram showing an example of an embodiment of an interference signal reducer 200 flowing into a receiver according to an embodiment of the present invention.

Referring to FIG. 4, the RF interference signal reducer 200 includes an interference signal reducer antenna 300, a first band-pass filter 800, a simulated signal shaping module 400, a first power combiner 500, a first 2 may further include a power combiner 502 and a control unit 600.

The RF interference signal attenuator 200 may be provided between the second band pass filter 802 of the original receiver and the low noise amplifier (LNA) 900. The RF interference signal reducer 200 may have a first band pass filter 800 built in. The first band-pass filter 800 can appropriately remove or reduce an RF interference signal flowing into a receiver in a desired frequency band. Here, the first band-pass filter 800 may have the same pass band as that of the second band-pass filter 802 of the original receiver.

The interference signal reducer antenna 300 may generate a reference signal. The interference signal reducing antenna 300 may be replaced with a reference signal generator.

The simulated signal shaping module 400 may further include a first variable delay line 402 and a 2xN path block 404 . Depending on the distance between the interfering signal source and the interfering receiver, the time required for the interfering signal to reach the interfering receiver may be different. In this case, the simulated signal shaping module 400 may reflect such a time delay.

The first variable delay line 402 can perform a time delay function within a specific range, and the 2xN path block 404 can perform a function of shaping a simulated signal. The implementation range of the time delay of the first variable delay line 402 can be determined by the spatial range between the interference source and the interference target receiver to be systematically processed by the RF interference signal reducer 200.

The 2xN path block 404 may be composed of 2xN delay lines and 2xN variable attenuators for shaping the simulated signal. Each of the 2xN delay lines may be configured to have a time delay difference by an arbitrary amount of time.

5 is a diagram showing an example of an embodiment of an RF interference signal reducer 200 flowing into a receiver according to another embodiment of the present invention.

The RF interference signal reducer 200 of FIG. 5 may further include a third power combiner 504 and a fourth power combiner 506 .

In general, interference cancellation or reduction performance can be confirmed by power detection of the output signal of the second power combiner 502 by the control unit 600 . Here, the second power combiner 502 may perform a subtraction circuit function. The output of the second power combiner 502 may be a difference between an output signal of the second band pass filter 802 and an output signal of the RF simulation signal shaping module 400 . Since the second power combiner 502 detects the size of the output signal difference, it may be difficult to determine which signal is larger or smaller.

Referring to FIG. 6 again, the RF interference signal reducer 200 converts some of the output signals of the third power combiner 504 and some of the output signals of the fourth power combiner 506 to the controller ( 600) can be applied. The RF interference signal attenuator 200 detects power based on the signal applied to the control unit 600, and among the output signal of the second band-pass filter 802 and the output signal of the simulated signal shaping module 400 You can check which signal is bigger. Through this, even if the magnitude of the error signal is detected by power, it is possible to easily distinguish whether the error signal has a negative sign or a positive sign, so that the interference removal or reduction performance of the RF interference signal reducer 200 can be easily confirmed. can

6 is a diagram showing an example of an embodiment of an RF interference signal reducer 200 flowing into a receiver according to another embodiment of the present invention.

Referring to FIG. 6 , the RF interference signal reducer 200 may further include a second variable delay line 1000 . When there is a time delay between a path from the interference signal reducer antenna 300 to the low noise amplifier 900 and a path from the receiver antenna 100 to the low noise amplifier 900, the second variable delay line By adding (1000), it is possible to provide a function that can easily adjust the time delay systematically.

7A is a graph showing performance of the RF interference signal reducer 200 when the RF interference signal reducer 200 is applied to the front end of the original receiver.

As a diagram showing the performance of the RF interference signal reducer 200 implemented as shown in FIG. 3, the RF interference signal reducer 200 may be applied to a front end of a band-pass filter of the original receiver. Therefore, it may not be easy for the RF interference signal reducer 200 to remove the interference signal of the desired band.

Referring to FIG. 4A , nulls may be formed at center frequencies F1, F2, and F3 when the performance of the RF interference signal reducer 200 is maximized. As for the interference signal reduction performance, case 1, case 2, and case 3 have different center frequencies, so the degree of interference signal removal is different depending on the frequency, but in terms of power detection, the same power is detected, so it can be judged to have the same interference reduction performance. there is. Therefore, it may not be easy to properly operate the RF interference signal reducer 200 in a desired frequency band.

For example, an interference signal may exist at the center frequency F1. At this time, the performance of the RF interference signal reducer 200 may be maximized at the center frequency F2 or F3.

7B is a graph showing the performance of the RF interference signal reducer 200 when the RF interference signal reducer 200 is applied to the rear end of the band pass filter (center frequency F1) of the original receiver, and FIG. 7C is the band pass filter of the original receiver. It is a graph showing the performance of the RF interference signal reducer 200 when the RF interference signal reducer 200 is applied at the rear end of (center frequency F2).

7b and 7c show that the first bandpass filter 800 may be provided at the rear end of the interference signal reducing antenna 300 of the RF interference signal reducer 200, and the RF interference signal reducer 200 ) may be applied after the second bandpass filter 802 of the original receiver.

Referring to FIG. 7B, when the center frequency of the band-pass filter is F1, the interference signal is properly removed, and the null of the interference cancellation performance can be formed at the F1 frequency. 4C shows that when the center frequency of the bandpass filter is F2, the null of the interference cancellation performance is formed at F2 when the RF interference signal reducer 200 operates properly.

If the RF interference signal reducer 200 as described above is used, even if the degree of spatial separation of wireless communication systems providing different services is small, the effect of interference is small and the systems can coexist, thereby providing smoother services. It is possible to provide a more stable service because more efficient frequency resources can be used, and an interference margin of the system can be obtained in terms of the system.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable medium may be specially designed and configured for the present invention or may be known and usable to those skilled in computer software.

Examples of computer readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the claims below. You will be able to.

100 Receiver antenna 200 RF interference signal reducer
300 Interference signal reducer antenna 400 Copy signal shaping module
402 first variable delay line 404 2xN path block
500 first power combiner 502 second power combiner
504 third power combiner 506 fourth power combiner
600 control unit 700 receiver unit
800 first bandpass filter 802 second bandpass filter
900 low noise amplifier (LNA) 1000 second variable delay line

Claims (1)

an interference signal reducer antenna outputting a reference signal;
a first band-pass filter receiving a reference signal from the interference signal reducer antenna and limiting a reception band;
a simulated signal shaping module for simulating a signal having the same amplitude and phase as an interference signal based on the signal applied from the first band-pass filter;
a fourth power combiner which samples and transmits a part of the output of the simulated signal shaping module to the control unit and transmits the remaining signals to the first power combiner;
a first power combiner that combines the simulated signal with the receiving device to be interfered with and cancels the interference signal present in the receiving path;
a second band pass filter receiving signals from the receiver antenna;
a second variable delay line for receiving a signal from the second band-pass filter and adjusting a delay time of the received signal;
a third power combiner receiving signals from the second variable delay line, transferring some of the signals to the control unit, and transferring the remaining signals to the first power combiner;
a second power combiner that samples and transmits a part of the output of the first power combiner to the controller and transmits the remaining output signal of the first power combiner to the receiver; and
And a control unit for detecting the degree to which the interference signal has been removed and controlling the simulated signal shaping module and the second variable delay line according to the degree to which the interference signal has been removed.
RF interference signal reduction device for receiver.

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