KR102441528B1 - Method and apparatus for estimating input information of finite impulse response filter in in-band full duplex transceiver - Google Patents

Abstract

A method and apparatus for estimating input information of an FIR filter in a co-band full-duplex transceiver are disclosed. The estimation method includes: obtaining a first signal by performing FFT on baseband equivalent information on a signal obtained by subtracting an output signal of an FIR filter from a self-transmission interference signal using a first training signal in a first period; obtaining a second signal by performing FFT on baseband equivalent information on the self-transmission interference signal using the second training signal, and estimating input information of the FIR filter using the first and second signals may include

Description

Method and apparatus for estimating input information of FIR filter in same-band full-duplex transceiver

The present invention relates to a method and apparatus for estimating input information of an FIR filter by processing in a frequency domain in a co-band full-duplex transceiver.

Currently, most of the wireless communication systems employ a half-duplex method. Since the half-duplex method transmits or receives by distributing time or frequency, orthogonality may be maintained between transmission and reception. However, this half-duplex method wastes resources (time or frequency).

The in-band full duplex (IFD) method is proposed as a solution to solve the inefficiency of the half-duplex method. The same-band full-duplex method is a technology that enables simultaneous transmission and reception in the same band. Since the same-band full-duplex method can theoretically increase the link capacity up to 2 times, it is an indispensable technology to achieve 1000 times the traffic capacity required for 5G mobile communication.

However, the same-band full-duplex (IFD) method has a disadvantage in that the self-transmission signal is introduced into the receiver, and the self-transmission signal is much stronger than the effective reception signal, which causes the self-transmission signal to act as a self-interference signal. For self-interference cancellation (SIC), there is an antenna area SIC technology that physically separates a transmit antenna and a receive antenna significantly. A technology for lowering the self-interference level through the antenna domain SIC technology and removing the remaining self-interference in the digital domain is in the commercialization stage. However, this technique is not easy to apply to small devices due to the physical separation between the transmitting and receiving antennas.

In order to apply the same-band full-duplex (IFD) method to a small device, a technique for eliminating magnetic interference in the analog circuit area without the aid of physical separation between antennas is required. SIC technology in analog circuit area is largely divided into passive SIC technology and active SIC technology. Passive SIC technology can easily obtain SIC gain using passive elements, but there is a limit to the gain. On the other hand, active SIC technology uses an adaptive analog FIR (Finite Impulse Response) filter circuit to achieve high SIC technology gains compared to passive SIC technology. However, the existing active SIC technology has a problem in that it cannot continuously maintain a high SIC gain while rapidly adapting to changes in the surrounding environment over a wide band.

An object of the present invention is to provide a method and apparatus for estimating input information of an FIR filter in a frequency domain so that a same-band full-duplex transceiver has a high SIC gain.

According to an embodiment of the present invention, there is provided a method for estimating input information of the FIR filter in a co-band full-duplex transceiver including a finite impulse response (FIR) filter that receives a transmission signal and removes a self-transmission interference signal. In the method, in a first period, after setting the degree of attenuation of the FIR filter to a predetermined value, generating and transmitting a first training signal, in the first period, the FIR filter in the self-transmission interference signal Obtaining a first signal by performing FFT (Fast Fourier Transform) on baseband equivalent information on a signal obtained by subtracting an output signal of , performing FFT on the baseband equivalent information on the self-transmission interference signal to obtain a second signal, and estimating input information of the FIR filter using the first signal and the second signal may include

The estimating may include calculating a third signal by subtracting the first signal from the second signal, and calculating input information of the FIR filter by using the third signal.

The acquiring of the second signal may include acquiring the second signal after suppressing generation of an output signal of the FIR filter.

The first training signal and the second training signal may be the same signal.

The same-band full-duplex transceiver may include a transmitter that generates and transmits the transmission signal, and a receiver that converts and demodulates a received signal into a baseband signal, wherein measuring the first signal includes: in the first period , obtaining the first signal by using an output signal of an analog-to-digital converter included in the receiver.

The acquiring of the second signal may include acquiring the second signal using an output signal of the analog-to-digital converter in the second period.

The input information of the FIR filter may include a linear component and a nonlinear component.

The first period and the second period may be included in a field for transmitting the first training signal and the second training signal in a time domain frame.

The first training signal and the second training signal may be transmitted over one or more orthogonal frequency division multiplexing (OFDM) symbol intervals, respectively.

According to another embodiment of the present invention, a co-band full-duplex transceiver is provided. The same-band full-duplex transceiver includes a transmitter that generates and transmits a transmit signal, a receiver that converts a received signal into a baseband signal and demodulates, a finite impulse response (FIR) filter that receives the transmit signal and removes a self-transmission interference signal; And it may include an estimator that sets the degree of attenuation of the FIR filter and estimates the input information of the FIR filter by performing Fast Fourier Transform (FFT) on the output information of the analog-to-digital converter included in the receiver.

The transmitter may generate and transmit a first training signal in a first period and generate and transmit a second training signal in a second period, wherein the estimator determines the degree of attenuation of the FIR filter in the first period. After setting to a value of , FFT is performed on the output information of the analog-to-digital converter to obtain a first signal, and in the second period, FFT is performed on the baseband equivalent information for the self-transmission interference signal, and a second signal can be obtained.

The estimator may estimate input information of the FIR filter by using the first signal and the second signal.

The estimator may calculate a third signal by subtracting the first signal from the second signal, and may calculate input information of the FIR filter using the third signal.

The estimator may set an attenuation degree of the FIR filter in the second period to suppress an output signal of the FIR filter.

The transmission signal may be an output signal of a power amplifier included in the transmitter.

The co-band full-duplex transceiver may further include an antenna for transmitting the transmission signal and receiving the received signal, and a splitter for transmitting the transmission signal to the antenna and transmitting the received signal to the receiver.

The input information of the FIR filter may include a linear component and a nonlinear component.

The first training signal and the second training signal may be the same signal.

According to another embodiment of the present invention, a transmitter that generates and transmits a transmission signal, a receiver that converts a received signal into a baseband signal, and a Finite Impulse Response (FIR) that receives the transmission signal and removes a self-transmission interference signal A method for estimating input information of the FIR filter in same-band full-duplex transmission/reception including a filter is provided. In the method, in a first period, after setting the degree of attenuation of the FIR filter to a predetermined value, generating and transmitting a first training signal, in the first period, of the analog-to-digital converter included in the receiver performing FFT on the output information to obtain a first signal, in a second period, generating and transmitting a second training signal in a state in which the output signal of the FIR filter is suppressed, in the second period , performing FFT on the output information of the analog-to-digital converter to obtain a second signal, and estimating input information of the FIR filter using the first signal and the second signal can

The estimating may include calculating a third signal by subtracting the first signal from the second signal, and calculating input information of the FIR filter by using the third signal.

According to an embodiment of the present invention, a high SIC gain can be obtained by processing and estimating input information of the FIR filter in the frequency domain and setting the degree of attenuation of the FIR filter using this.

1 is a diagram illustrating a same-band full-duplex transceiver according to an embodiment of the present invention.
2 is a diagram illustrating a same-band full-duplex transceiver 1000' according to another embodiment of the present invention.
3 is a diagram illustrating a time domain frame structure according to an embodiment of the present invention.
4 is a flowchart illustrating a method of estimating input information of an FIR filter by processing it in a frequency domain according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, a terminal is a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR-MS) ), a subscriber station (subscriber station, SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE), and the like, and may refer to a terminal, MT, It may include all or some functions of AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the base station (base station, BS) is an advanced base station (advanced base station, ABS), a high reliability base station (high reliability base station, HR-BS), a Node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, a relay serving as a base station station, RS), may refer to a high reliability relay station (HR-RS) that serves as a base station, etc., and may refer to ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, HR It may include all or part of functions such as -RS.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, a terminal is a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR-MS) ), a subscriber station (subscriber station, SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE), and the like, and may refer to a terminal, MT, It may include all or some functions of AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the base station (base station, BS) is an advanced base station (advanced base station, ABS), a high reliability base station (high reliability base station, HR-BS), a Node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, a relay serving as a base station station, RS), may refer to a high reliability relay station (HR-RS) that serves as a base station, etc., and may refer to ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, HR It may include all or part of functions such as -RS.

Throughout the specification, a transceiver is a terminal, a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station , HR-MS), a subscriber station (subscriber station, SS), a portable subscriber station (PSS), an access terminal (AT), may refer to a user equipment (UE), etc., It may include all or part of functions such as terminal, MT, AMS, HR-MS, SS, PSS, AT, and UE.

In addition, the transceiver (transceiver) is a base station (base station, BS), an advanced base station (advanced base station, ABS), high reliability base station (high reliability base station, HR-BS), Node B (node B), advanced Node B (evolved node B, eNodeB), access point (AP), radio access station (RAS), base transceiver station (BTS), MMR (mobile multihop relay)-BS, base station role It may also refer to a relay station (RS), a high reliability relay station (HR-RS), etc. that perform the role of a base station, ABS, NodeB, eNodeB, AP, RAS, BTS, MMR- It may include all or some functions of BS, RS, HR-RS, and the like.

1 is a diagram illustrating a same-band full-duplex transceiver 1000 according to an embodiment of the present invention.

1, the same-band full-duplex transceiver 1000 according to an embodiment of the present invention includes a baseband digital domain transceiver 100, an analog circuit domain transceiver 200, and an antenna unit 300. include

The baseband digital domain transceiver 100 includes a transmission data generator 110 and an estimator 120 . Although not shown in FIG. 1 , the baseband digital domain transceiver 100 may further include a reception data demodulation generator. The transmission data generator 110 generates a digital signal corresponding to data to be transmitted by performing encoding and modulation. In FIG. 1, an output signal of the transmission data generator 110, that is, a baseband time domain signal, is represented by x[m]. The received data demodulation generator (not shown in FIG. 1) performs demodulating and decoding on the received data. The estimator 120 sets the attenuation degree for each tap of the finite impulse response (FIR) filter 240 . In addition, the estimator 120 according to the embodiment of the present invention performs a function of estimating the input information of the FIR filter 240 by processing in the frequency domain in order to set the attenuation degree for each tap of the FIR filter 240 .

The analog circuit area transceiver 200 includes a digital analog converter (DAC) 210 , a mixer 220 , a power amplifier (PA) 230 , an FIR filter 240 , and a signal combiner 250 . ), a low noise amplifier (LNA) 260 , an integrator 270 and an analog digital converter (ADC) 280 . The transmission data generator 110 , the DAC 210 , the mixer 220 , and the PA 230 form a transmitter. In addition, the signal combiner 250 , the LNA 260 , the integrator 270 , the ADC 280 and the reception data demodulation generator form a receiver.

The DAC 210 converts a digital signal into an analog signal, and the mixer 220 converts a baseband frequency signal into a radio frequency (RF) band signal using the carrier frequency f _C . The PA 230 amplifies and outputs the RF band signal. In FIG. 1 , the output signal of the DAC 210 is represented by x _b (t), and the output signal of the PA 230 , that is, the final transmission signal, is represented by s (t). The final transmission signal s(t) contains nonlinear components (harmonics component and phase noise component) due to the mixer 220 and the PA 230, and as described below, an estimator according to an embodiment of the present invention (120) estimates baseband equivalent frequency domain information for s(t) including nonlinear components.

The antenna unit 300 includes a transmit antenna 310 and a receive antenna 320 . The transmit antenna 310 transmits a transmit signal s(t) to the outside, and the receive antenna 320 receives the receive signal. Since the transmission antenna 310 and the reception antenna 320 are physically close to each other, the transmission signal s(t) flows in through the reception antenna 320 and acts as an interference signal, and this interference signal is a self-transmission interference signal. This is because the transceiver 1000 according to the embodiment of the present invention operates in the same-band full-duplex mode. The signal received through the reception antenna 320 includes not only a normal reception signal but also a self-transmission interference signal. In FIG. 1, the self-transmission interference signal is represented by y(t). As will be described below, in the embodiment of the present invention, the self-transmission interference signal y(t) may be removed by using the FIR filter 240 .

The FIR filter 240 receives the transmission signal s(t) and generates and outputs a signal that minimizes the self-transmission interference signal y(t). As shown in Figure 1, the FIR filter 240 according to the embodiment of the present invention is a plurality of delays (d ₀ ~ d _N-1 ), a plurality of attenuators (attenuator) (a ₀ ~ a _N-1 ) and a signal A coupler 241 is included.

Each of the plurality of delays d ₀ to d _N-1 has a fixed delay. The delay intervals between each delayer d _i (i=0,1,...,N-1) may be the same or all different, and may be divided into a plurality of groups having the same delay interval. Here, N denotes the total number of taps, and d _i (i=0,1,2,...,N-1) denotes a delay applied to the taps.

A plurality of attenuators (a ₀ ~ a _N-1 ) is respectively connected to the plurality of delay (d ₀ ~ d _N-1 ) attenuates the signal. The attenuation degree of each attenuator a _i (i=0,1,2...,N-1) is variable, and the attenuation degree is set by the estimator 120 . The value of the attenuation degree of each attenuator a _i (i=0,1,2...,N-1) may have one of magnitude, magnitude and phase, real value or complex value, and in the following description, attenuation for convenience The precision is explained assuming that it has a magnitude or a real value.

The signal combiner 241 combines the output signals of the plurality of attenuators a ₀ to a _N-1 . The signal combiner 241 adds and combines all of the signals output from the plurality of attenuators a ₀ to a _N-1 . In FIG. 1 , the output signal of the signal combiner 241 , that is, the output signal of the FIR filter 240 is represented by z(t).

The signal combiner 250 combines the received signal with the output signal of the FIR filter 240 and outputs it to the LNA 260 . The signal combiner 250 subtracts the signal output from the FIR filter 240 from the received signal and then combines the two signals. At this time, since the FIR filter 240 outputs a signal that minimizes the self-transmission interference signal y(t), the signal combiner 250 removes the self-transmission interference signal y(t) from the received signal. (260) is output. In FIG. 1, the output signal of the signal combiner 250 is represented by v(t).

The LNA 260 receives a received signal from which the self-transmission interference signal y(t) is removed from the signal combiner 250 , and removes noise from the input signal and amplifies the received signal. The integrator 270 converts the RF band signal into a baseband signal using the carrier frequency f _C . The ADC 260 converts an analog baseband signal into a digital signal.

2 is a diagram illustrating a same-band full-duplex transceiver 1000' according to another embodiment of the present invention.

2, the same-band full-duplex transceiver 1000' according to another embodiment of the present invention includes a baseband digital domain transceiver 100, an analog circuit domain transceiver 200', and an antenna unit ( 300'). Since the antenna unit 300 ′ is the same as that of FIG. 1 except that the antenna unit 300 ′ is composed of one transmitting and receiving antenna and the analog circuit area transmitting and receiving unit 200 ′ further includes a divider 290 , the description overlapping with FIG. 1 will be omitted. .

The antenna unit 300' includes a transmission/reception antenna 330 that simultaneously performs a reception function as well as a transmission function for the same-band full-duplex method. That is, a transmission signal is transmitted and a reception signal is received through the antenna 330 .

The analog circuit area transceiver 200 ′ further includes a divider 290 . The splitter 290 is connected to the antenna 330 and sends a transmit signal s(t) to the antenna 330 . And the splitter 290 transmits the received signal received from the antenna 330 to the receiving module (signal combiner 250, LNA 260, etc. in FIG. 1). That is, the splitter 290 according to an embodiment of the present invention serves to transmit a transmission signal to the antenna 330 and a reception signal to a reception module. The distributor 290 may be implemented as a circulator or an EBD (Electrical Balance Duplex). Circulators and EBDs are known to those of ordinary skill in the art to which the present invention pertains, and detailed descriptions thereof will be omitted.

Hereinafter, a method for estimating the estimation unit 120 by processing input information of the frequency FIR filter 240 in the frequency domain will be described. The input information z(t) of the FIR filter 240 includes a nonlinear component, and the estimator 120 according to an embodiment of the present invention includes baseband equivalent information of s(t) including the nonlinear component. is estimated by processing in the frequency domain. A method of estimating baseband equivalent information of z(t) described below will be described with reference to FIG. 2 , but may be equally applied to FIG. 1 .

First, in order to explain how the estimator 120 estimates input information of the FIR filter 240 , various signals of the same-band full-duplex transceiver 1000 ′ are mathematically modeled.

x[m] means a baseband oversampled or baseband sampled time domain signal. When the sampled signal passes through the DAC 210, a baseband analog signal x _b (t) as shown in Equation 1 below is generated.

In Equation 1, x[m] is x _b (m/W), and sinc(t) is defined as in Equation 2 below.

)의 선형 결합(Linear Combination)으로 표현할 수 있다는 샘플링 이론이 수학식 1에 적용된다. 수학식 1에서, W는 대역폭을 의미하며, 기저대역의 시스템 대폭일 수 도 있고 d배 오버샘플링(oversampling)된 대역폭일 수 있다. 아래에서는 설명의 편의상 W를 1배(d=1) 오버샘플링된 대역폭으로 가정하여 설명하였으나, d의 값은 다른 값으로 설정될 수 있다. The expression of Equation 1 is that the sampling theory is applied. That is, all baseband waveforms band-limited to W/2 have a coefficient (i.e., x[m]) given by the samples and an orthogonal basis (

), the sampling theory that can be expressed as a linear combination of ) is applied to Equation 1. In Equation 1, W denotes a bandwidth, and may be a system wide baseband or a d-fold oversampling bandwidth. In the following description, it is assumed that W is a bandwidth oversampled by one time (d=1) for convenience of description, but the value of d may be set to another value.

When x _b (t) passes through the mixer 220 , it becomes an RF signal, and when this RF signal passes through the PA 230 , it becomes a time domain input signal s(t) of the FIR filter 240 . If this s(t) is expressed mathematically, it becomes as in Equation 3 below.

는 x_b(t)가 PA(230)를 통과하면서 발생되는 비선형성분을 포함하는 RF 신호에 대한 등가 기저대역 신호를 의미한다. P는 PA(230)에 의해 증폭되는 송신전력을 의미하며, f_c는 믹서(220)의 반송 주파수를 의미한다. 아래에서, 수학식 3의 s(t)에 대한 주파수영역 표현식을 S(f)라 정의하며, 이때 f는 RF 주파수를 의미한다. in Equation 3

denotes an equivalent baseband signal with respect to an RF signal including a nonlinear component generated while x _b (t) passes through the PA 230 . P denotes transmit power amplified by the PA 230 , and f _c denotes a carrier frequency of the mixer 220 . Hereinafter, a frequency domain expression for s(t) in Equation 3 is defined as S(f), where f denotes an RF frequency.

1 and 2, the RF signal as in Equation 3 passes through the FIR filter 240, and the frequency domain expression for the transfer function of the FIR filter 240 is as Equation 4 below.

In Equation 4, d _q denotes a time delay of the q-th tap, and a _q denotes path attenuation of the q-th tap. Using the expressions of Equations 3 and 4, the frequency domain and time domain expressions for the output signal of the FIR filter 240 are as Equation 5 below.

Using the expressions of Equations 3 and 4, the self-transmission interference signal y(t) and its frequency domain expression are as shown in Equation 6 below.

와

는 각각 분배기(290)와 안테나(330)의 특성에 의해 생성되는 채널에 대한 다중 경로 i별 경로감쇄(attenuation)와 시간지연(time delay)를 의한다. N'는 채널에 대한 총 다중 경로 수를 의미한다.In Equation 6, h _ch (t) denotes a channel generated by the characteristics of the splitter 290 and the antenna 330, and H _ch (f) denotes a frequency domain expression of h _ch (t). and,

Wow

, respectively, are due to path attenuation and time delay for each multi-path i for the channel generated by the characteristics of the splitter 290 and the antenna 330 . N' means the total number of multi-paths for the channel.

Using the expressions of Equations 5 and 6, the frequency domain expression for the output signal v(t) of the signal combiner 250 is as Equation 7 below.

Next, a method for estimating input information of the FIR filter 240 by the estimator 120 according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4 . In the following description, it is assumed that the LNA 260, the integrator 270, and the ADC 280 have no hardware damage in each of Equations 5 to 7 above.

3 is a diagram illustrating a time domain frame structure according to an embodiment of the present invention.

As shown in FIG. 3 , the time domain frame according to the embodiment of the present invention includes an In-band Full Duplex (IFD) training field 410 and an IFD communication field 420 . The IFD training field 410 is a separate field for transmitting a training signal to estimate input information of the FIR filter 240 . In the IFD training field 410 , a first training signal 411 and a second training signal 412 are transmitted. The first training signal 411 and the second training signal 412 are separately generated signals for estimating input information of the FIR filter 240 , and the two signals are allocated in the frequency domain. In addition, the first training signal 411 and the second training signal 412 are transmitted over one or more orthogonal frequency division multiplexing (OFDM) symbol intervals, respectively. Meanwhile, the first training signal 411 and the second training signal 412 are the same signal. The IFD communication field 420 is a section in which data for same-band full-duplex transmission/reception is transmitted.

4 is a flowchart illustrating a method of estimating input information of the FIR filter 240 by processing it in a frequency domain according to an embodiment of the present invention.

First, the estimator 120 obtains V[k] after Self-Interference Cancellation (SIC) is performed by using the first training signal 411 ( S410 ). The estimator 120 sets the degree of attenuation (a _i (i=0,1,2...,N-1)) of the FIR filter 240 to an arbitrary initial value. In addition, the transmission data generator 110 generates a first training signal 411 , and the estimator 120 calculates the output information (V(k)) of the signal combiner 250 for the first training signal 411 . acquire Here, V[k] is a signal obtained by performing Fast Fourier Transform (FFT) on the output of the ADC 280 due to the first training signal 411 , and the estimator 120 inputs the output of the ADC 280 . Then, FFT is performed to obtain V(k). That is, V[k] is a value obtained by performing FFT on information of the baseband version (equivalent) of v(t) (ie, output information of the ADC 280 ). If such V(k) is expressed mathematically, it is shown in Equation 8 below.

In Equation 8, k denotes a subcarrier index, and F denotes the size of the FFT. V(k) in Equation (8) can be said to be a baseband sampled version of Equation (7). Meanwhile, in step S410, the degree of attenuation (a _i (i=0,1,2...,N-1)) of the FIR filter 240 is set to an arbitrary value, and the time delay (d ₀ to d _N-1 ) is Since it is a fixed value, H _fir (k) in Equation 8 can be calculated by Equation 9 below.

In Equation 9, f _s denotes a baseband sampling rate, and H _fir (k) may be a baseband sampled version of H _fir (f) defined in Equation 4.

The estimator 120 obtains Y(k) corresponding to the self-interference signal by using the second training signal 412 ( S420 ). That is, the estimator 120 performs FFT on the information of the baseband version (equivalent) of the self-transmission interference signal y(t) (that is, the output information of the ADC 280), and the following equation We get Y(k) equal to 10.

Y(k) as in Equation (10) can be said to be a baseband sampled version of Y(f) defined in Equation (6).

In order for the estimator 120 to obtain Y(k), only the self-transmission interference signal y(t) needs to be introduced into the estimator 120 . As a method in which the self-transmission interference signal y(t) flows into the estimator 120 , the estimator 120 determines the degree of attenuation (a _i (i=0,1,2...,N) of the FIR filter 240 . -1)) can be set to a very high value. Through this, it is possible to physically suppress the generation of the output signal of the FIR filter 240, and only the self-transmission interference signal y(t) is passed through the LNA 260, the integrator 270 and the ADC 280 to the estimator 120 ) is entered in In this case, the estimator 120 performs FFT on the signal input from the ADC 280 to obtain Y(k).

Next, the estimator 120 estimates the input information of the FIR filter 240 (S430). If Equation 8 is subtracted from Equation 10, Z(k) is obtained as in Equation 11 below. That is, the estimator 120 may calculate Z(k) by subtracting V(k) measured in step S410 from Y(k) measured in step S420 . Z(k) calculated in this way is expressed as Equation 11 below.

As described in Equation 9, since H _fir (k) is a calculated value, the estimator 120 can estimate S(k), which is input information of the FIR filter 240, using Equation 11. have. S(k) corresponds to baseband equivalent frequency domain input information of the FIR filter 240 . The expression for S(k) estimated in this way is as Equation 12 below.

Meanwhile, if the estimator 120 performs inverse FFT (IFFT) on Equation 12, baseband equivalent time domain input information of the FIR filter 240 may be obtained.

Meanwhile, the estimator 120 calculates the degree of attenuation (a _i (i=0,1,2...,N-1)) of the FIR filter 240 in order to minimize the self-interference signal using S(k). Reset. That is, the estimator 120 updates the degree of attenuation set as the initial value in step S410 to a value for minimizing the self-interference signal.

According to this embodiment of the present invention, input information of the FIR filter 240 including a non-linear component as well as a linear component is processed and estimated in the frequency domain, and the degree of attenuation of the FIR filter 240 is set using this. By doing so, a high SIC gain can be obtained.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. is within the scope of the right.

Claims (20)

A method of estimating input information of the FIR filter in the same-band full-duplex transceiver including a finite impulse response (FIR) filter that receives a transmission signal and removes a self-transmission interference signal, the method comprising:
In a first period, after setting the degree of attenuation of the FIR filter to a predetermined value, generating and transmitting a first training signal corresponding to the transmission signal;
obtaining a first signal by performing FFT (Fast Fourier Transform) on baseband equivalent information on a signal obtained by subtracting the output signal of the FIR filter from the self-transmission interference signal in the first period;
generating and transmitting a second training signal corresponding to the transmission signal in a second period;
in the second period, performing FFT on baseband equivalent information on the self-transmission interference signal to obtain a second signal; and
and estimating input information of the FIR filter by using the first signal and the second signal. The method of claim 1,
The estimating step is
calculating a third signal by subtracting the first signal from the second signal; and
and calculating input information of the FIR filter by using the third signal. The method of claim 1,
The acquiring of the second signal includes acquiring the second signal after suppressing generation of an output signal of the FIR filter. According to claim 1,
wherein the first training signal and the second training signal are the same signal. The method of claim 1,
The same-band full-duplex transceiver includes a transmitter for generating and transmitting the transmission signal, and a receiver for converting and demodulating the received signal into a baseband signal,
The step of measuring the first signal includes, in the first period, acquiring the first signal using an output signal of an analog-to-digital converter included in the receiver. 6. The method of claim 5,
The acquiring of the second signal includes acquiring the second signal using an output signal of the analog-to-digital converter in the second period. According to claim 1,
The input information of the FIR filter includes a linear component and a non-linear component. According to claim 1,
wherein the first period and the second period are included in a field for transmitting the first training signal and the second training signal in a time domain frame. According to claim 1,
The first training signal and the second training signal are each transmitted over one or more orthogonal frequency division multiplexing (OFDM) symbol intervals. a transmitter that generates and transmits a transmission signal;
a receiver that converts and demodulates the received signal into a baseband signal;
A Finite Impulse Response (FIR) filter that receives the transmission signal and removes a self-transmission interference signal, and
and an estimator for setting the degree of attenuation of the FIR filter and estimating input information of the FIR filter by performing FFT (Fast Fourier Transform) on the output information of the analog-to-digital converter included in the receiver,
The transmitter generates and transmits a first training signal in a first period and generates and transmits a second training signal in a second period,
The estimator is
In the first period, after setting the degree of attenuation of the FIR filter to a predetermined value, FFT is performed on the output information of the analog-to-digital converter to obtain a first signal,
In the second period, the same-band full-duplex transceiver obtains a second signal by performing FFT on the baseband equivalent information on the self-transmission interference signal. delete 11. The method of claim 10,
The estimator estimates the input information of the FIR filter by using the first signal and the second signal, the same-band full-duplex transceiver. 13. The method of claim 12,
The estimator calculates a third signal by subtracting the first signal from the second signal, and calculates input information of the FIR filter by using the third signal. 11. The method of claim 10,
The estimator sets an attenuation degree of the FIR filter in the second period to suppress an output signal of the FIR filter. a transmitter that generates and transmits a transmission signal;
a receiver that converts and demodulates the received signal into a baseband signal;
A Finite Impulse Response (FIR) filter that receives the transmission signal and removes a self-transmission interference signal, and
and an estimator for setting the degree of attenuation of the FIR filter and estimating input information of the FIR filter by performing FFT (Fast Fourier Transform) on the output information of the analog-to-digital converter included in the receiver,
The transmission signal is a co-band full-duplex transceiver that is an output signal of a power amplifier included in the transmitter. a transmitter that generates and transmits a transmission signal;
a receiver that converts and demodulates the received signal into a baseband signal;
A Finite Impulse Response (FIR) filter that receives the transmission signal and removes a self-transmission interference signal, and
and an estimator for setting the degree of attenuation of the FIR filter and estimating input information of the FIR filter by performing FFT (Fast Fourier Transform) on the output information of the analog-to-digital converter included in the receiver,
An antenna for transmitting the transmission signal and receiving the received signal, and
The same-band full-duplex transceiver further comprising a splitter for sending the transmitted signal to the antenna and sending the received signal to the receiver. a transmitter that generates and transmits a transmission signal;
a receiver that converts and demodulates the received signal into a baseband signal;
A Finite Impulse Response (FIR) filter that receives the transmission signal and removes a self-transmission interference signal, and
and an estimator for setting the degree of attenuation of the FIR filter and estimating input information of the FIR filter by performing FFT (Fast Fourier Transform) on the output information of the analog-to-digital converter included in the receiver,
The input information of the FIR filter includes a linear component and a nonlinear component. 11. The method of claim 10,
The same-band full-duplex transceiver, wherein the first training signal and the second training signal are the same signal. In the same-band full-duplex transmission/reception comprising a transmitter that generates and transmits a transmission signal, a receiver that converts a received signal into a baseband signal, and a finite impulse response (FIR) filter that receives the transmission signal and removes a self-transmission interference signal, As a method of estimating input information of the FIR filter,
In a first period, after setting the degree of attenuation of the FIR filter to a predetermined value, generating and transmitting a first training signal corresponding to the transmission signal;
In the first period, performing FFT on the output information of the analog-to-digital converter included in the receiver to obtain a first signal;
In a second period, in a state in which the output signal of the FIR filter is suppressed, generating and transmitting a second training signal corresponding to the transmission signal;
In the second period, performing FFT on the output information of the analog-to-digital converter to obtain a second signal, and
and estimating input information of the FIR filter by using the first signal and the second signal. 20. The method of claim 19,
The estimating step is
calculating a third signal by subtracting the first signal from the second signal; and
and calculating input information of the FIR filter by using the third signal.

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