KR20160051639A - In-band full duplex transceiver and interference cancealation method thereof - Google Patents

Abstract

An in-band full duplex transceiver and a method for canceling interference thereof are disclosed. The same-band full-duplex transceiver may include an antenna, a distributor for sending a transmission signal to an antenna, a receiver for transmitting a reception signal received through an antenna to a reception module, and a FIR filter for receiving a transmission signal. Here, the FIR filter uses the second information which is the baseband equivalent frequency information of the self-transmission interference signal contained in the first information which is the baseband equivalent frequency information of the transmission signal and the signal which is output from the reception output terminal of the distributor, The transmission interference signal can be removed.

Description

≪ Desc / Clms Page number 1 > IN-BAND FULL DUPLEX TRANSCEIVER AND INTERFERENCE CANCEALATION METHOD THEREOF &

The present invention relates to a same-band full duplex transceiver and a method of canceling interference.

Currently, the wireless communication system adopts most of the half duplex method. The half-duplex scheme is able to maintain orthogonality between transmission and reception by transmitting or receiving time or frequency division. However, this half-duplex scheme not only wastes resources (time or frequency) but also has a difficulty in multi-hop relay between mobile small cells, and a separate overhead is required to solve the hidden node problem .

The in-band Full Duplex scheme is presented as a solution to overcome the inefficiency of the half-duplex scheme. The same-band full-duplex scheme is a technology capable of transmitting and receiving simultaneously in the same band. The same-band full-duplex scheme can theoretically increase the link capacity up to twice, which is indispensable technology for achieving the 1000 times traffic capacity required for 5G mobile communication.

However, the same-band full-duplex scheme has a disadvantage in that a self-transmitted signal flows into a receiver, and a self-transmitted signal acts as a magnetic interference signal much stronger than an effective received signal. There is an antenna area SIC technology that physically separates the transmission antenna and the reception antenna physically for self-interference cancellation (SIC). Antenna Region A technology that reduces the level of magnetic interference through SIC technology and removes the remaining magnetic interference in the digital domain is called ICS (Interference Cancellation System) technology. The problem of this ICS technique is that it can not be applied to small devices due to the physical separation between transmitting and receiving antennas.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a same-band full duplex transceiver that eliminates interference and a method of canceling interference.

According to an embodiment of the present invention, a same-band full duplex transceiver is provided. Wherein the same bandwidth full duplex transceiver comprises: an antenna; a distributor for transmitting a transmission signal to the antenna and for transmitting a reception signal received through the antenna to a reception module via a reception output; and a baseband equivalent of the transmission signal A FIR (Finite Impulse Response) method that removes the MIMO interference signal using first information which is frequency information and second information which is baseband equivalent frequency information of a self transmission interference signal included in a signal output from the reception output terminal, Filter.

The FIR filter includes a plurality of delayers for receiving and delaying the transmission signals, a plurality of attenuators connected to the plurality of delayers for attenuating the signals, a signal combiner for combining output signals of the plurality of attenuators, And a controller for setting the degree of attenuation of the plurality of attenuators so as to eliminate the self-transmitting interference signal.

The controller may set the degree of attenuation using the first information and the second information.

The degree of delay of the plurality of delay units may be fixed.

The FIR filter may further include a power amplifier for outputting the transmission signal and a signal combiner for combining a signal output from the reception output terminal and a signal output from the FIR filter, And the signal combiner.

The controller may set the degree of attenuation to minimize a mean square error between the magnetic transmission interference signal and the output signal of the FIR filter.

The receiving module may include a low noise amplifier, an integrator, and an analog-to-digital converter for converting the output of the integrator to a digital signal, the first information comprising at least one of the amplifier, the integrator and the analog- (Fast Fourier Transform) signal after passing through a converter.

The second information may be a fast Fourier transformed signal after passing the magnetic transmission interference signal through the amplifier, the integrator, and the analog-digital converter.

According to another embodiment of the present invention, a same-band full duplex transceiver is provided. Wherein the same-band full-duplex transceiver includes an antenna, a transmission output terminal for transmitting a transmission signal to the antenna, a reception signal received through the antenna to a reception module, a reception output terminal for outputting the reception signal, And a second output terminal for receiving the first signal and outputting the first information, which is frequency response information of the transmission signal, and a frequency of a self transmission interference signal included in a signal output from the reception output terminal, And an FIR (Finite Impulse Response) filter that removes the self transmission interference signal using second information that is response information.

The distributor may include a hybrid transformer that transmits the transmission signal to the antenna and transmits the reception signal to the reception module, and a balance network that is connected to the hybrid transformer and controls an impedance corresponding to the impedance flowing to the antenna. And the first signal may be a signal output to the junction of the hybrid transformer and the balance network.

The FIR filter includes a plurality of delayers for receiving and delaying the first signals, a plurality of attenuators connected to the plurality of delayers for attenuating the signals, a signal combiner for combining the output signals of the plurality of attenuators, And a controller configured to set a degree of attenuation of the plurality of attenuators so as to eliminate the magnetic transmission interference signal. The controller may set the degree of attenuation using the first information and the second information.

The receiving output terminal may include a first receiving output terminal and a second receiving output terminal. The second signal outputted from the first receiving output terminal and the third signal outputted from the second receiving output terminal may be signals whose phases are inverted from each other have.

Wherein the same band full duplex transceiver comprises a first signal combiner for combining the second signal and the third signal, a second signal combiner for combining the output of the first signal combiner and the output of the FIR filter, And the FIR filter may be located between the contact and the second signal combiner.

The receiving module may include a low noise amplifier, an integrator, and an analog-to-digital converter for converting the output of the integrator to a digital signal, the first information comprising at least one of the amplifier, the integrator and the analog- (Fast Fourier Transform) signal after passing through a converter.

The second information may be a fast Fourier transformed signal after passing the magnetic transmission interference signal through the amplifier, the integrator, and the analog-digital converter.

According to another embodiment of the present invention, there is provided a method for removing interference in a same-band full duplex transceiver including an antenna and a distributor for sending a transmission signal through the antenna and for sending a reception signal received through the antenna to a reception module do. The interference cancellation method may include generating first information that is baseband equivalent frequency information of the transmission signal, generating second information that is baseband equivalent frequency information of a self transmission interference signal generated in the reception module by the transmission signal, And removing the self-transmitted interference signal using the first information and the second information.

The removing may include delaying the transmission signal, attenuating the delayed transmission signal using the first information and the second information, and combining the attenuated transmission signal have.

The removing may further comprise subtracting the attenuated transmission signal from the magnetic transmission interfering signal.

According to an embodiment of the present invention, a magnetic interference interference signal can be removed using a finite impulse response (FIR) filter.

1 is a diagram of a same-band full duplex transceiver according to an embodiment of the present invention.
2 is a diagram illustrating an FIR filter according to an embodiment of the present invention.
3 is a conceptual diagram illustrating a method of estimating X (k) in the same band full duplex transmission / reception of FIG.
4 is a conceptual diagram illustrating a method of estimating Y (k) in the same-band full duplex transceiver of FIG.
FIG. 5 is a flowchart illustrating a method of canceling interference of a same-band full duplex transceiver according to an embodiment of the present invention. Referring to FIG.
6 is a diagram illustrating a same-band full duplex transceiver according to another embodiment of the present invention.
7 is a conceptual diagram illustrating a method of estimating X (k) in the same-band full duplex transceiver of FIG.
8 is a conceptual diagram illustrating a method of estimating Y (k) in the same-band full duplex transceiver of FIG.
9 is a flowchart illustrating a method of canceling interference of a same-band full duplex transceiver according to another 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 skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, a terminal is referred to as a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station ), A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE) AMS, HR-MS, SS, PSS, AT, UE, and the like.

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) BS, RS, HR, RS, etc.) may be referred to as a high reliability relay station (HR-RS) -RS, and the like.

Throughout the specification, a transceiver may be a terminal, a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station , An HR-MS, a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE) MS, AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the transceiver includes a base station (BS), an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, an eNodeB, an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) And may be referred to as a relay station (RS), a high reliability relay station (HR-RS) serving as a base station, etc., and may be referred to as an ABS, a Node B, an eNodeB, an AP, a RAS, a BTS, BS, RS, HR-RS, and the like.

1 is a diagram of a same-band full duplex transceiver 100 in accordance with an embodiment of the present invention.

1, the same-band full duplex transceiver 100 includes a digital signal generator 110, a digital-to-analog converter (DAC) 120, a mixer 130, A power amplifier (PA) 140, a distributor 150, an antenna 160, a signal combiner 170, a low noise amplifier (LNA) 180, an integrator 190, An analog-to-digital converter (ADC) 200, a digital signal processor 210 and a finite impulse response (FIR) filter 220.

The digital signal generation unit 110 generates a digital signal corresponding to the data to be transmitted. The DAC 120 converts an analog signal into a digital signal and the mixer 130 converts a baseband frequency signal into a radio frequency band signal using a carrier frequency f _C. The PA 140 amplifies and outputs the RF band signal. In FIG. 1, a transmission signal output from the PA 140 is denoted by x (t). The transmission signal x (t) is input to the distributor 150 and the FIR filter 220. The DAC 120, the mixer 130, and the PA 140 constitute a part of the transmission module.

The distributor 150 is connected to the antenna 160 and sends the transmission signal x (t) to the antenna 160. [ Then, the distributor 150 sends the received signal received from the antenna 160 to the receiving module (the signal combiner 170, the LNA 180, etc.) of FIG. That is, the distributor 150 according to the embodiment of the present invention sends the transmission signal to the antenna 160 and sends the reception signal to the reception module. The distributor 150 may be implemented as a circulator or an electrical balance duplex (EBD). The circulator and the EBD will be apparent to those skilled in the art, and will not be described in detail.

The antenna 160 simultaneously performs the reception function as well as the transmission function for the same-band full-duplex manner. That is, the transmission signal is transmitted through the antenna 160 and the reception signal is received.

The signal output from the divider 150 to the signal combiner 170 includes not only the self-received signal of the same-band full duplex transceiver 100 but also a self-transmitted interference signal. The transmission signal x (t) is transmitted to the antenna 160 through the distributor 150, but some of the transmission signal x (t) flows into the reception module (LNA or the like) and acts as an interference signal. This is because the transceiver according to the embodiment of the present invention operates in the same band full duplex manner. In the following description, the self-transmitted interference signal is denoted by y (t). On the other hand, as described below, in the embodiment of the present invention, this magnetic transmission interference signal y (t) is removed by using the FIR filter 220. [

The FIR filter 220 receives the transmission signal x (t) and generates and outputs a signal that minimizes the magnetic transmission interference signal y (t). The specific configuration and operation of the FIR filter 220 will be described in detail below with reference to FIG.

The signal combiner 170 combines the received signal and the output signal of the FIR filter 220 and outputs the combined signal to the LNA 180. The signal combiner 170 subtracts the signal output from the FIR filter 220 from the received signal and combines the two signals. At this time, since the FIR filter 220 outputs a signal that minimizes the magnetic transmission interference signal y (t) as described below, the signal combiner 170 generates the magnetic transmission interference signal y (t) And outputs the signal to the LNA 180.

The LNA 180 receives the reception signal from which the magnetic transmission interference signal y (t) has been removed from the signal combiner 170, and removes and amplifies noise from the input signal. The integrator 190 converts the RF band signal into a baseband signal using the carrier frequency f _C. The ADC 200 converts an analog baseband signal into a digital signal, and the digital signal processor 210 demodulates the digital signal. Meanwhile, the digital signal processing unit 210 may include a module for performing digital SIC (Self-Interference Cancellation) on the sampled signal passed through the ADC 200 and a module for demodulating the received signal from the digital SIC . The LNA 180, the integrator 190 and the ADC 200 constitute a part of the receiving module.

2 is a diagram illustrating an FIR filter 220 according to an embodiment of the present invention.

2, the FIR filter 220 according to the embodiment of the present invention includes a plurality of delay units d ₀ to d _N-1 , a plurality of attenuators g ₀ to g _N-1 , A combiner 221, a control unit 222, an X (k) setting unit 223, and a Y (k) setting unit 224.

Each of the plurality of delay units (d ₀ to d _N-1 ) has a fixed delay. Each retarder _{(d i (i = 0,1,} ..., N-1)) between delay interval may be the same or different from both all it can be divided into a plurality of groups each having a delay equal distance from each other. Where N denotes the total number of taps and d _i (i = 0,1,2, ..., N-1) denotes the delay applied to the tap.

The plurality of attenuators g ₀ to g _{N-1 are} connected to a plurality of delay units d ₀ to d _N-1 , respectively, to attenuate the signal. The degree of attenuation of each attenuator g _i (i = 0, 1, 2, ..., N-1) is variable, and the degree of attenuation is set by the control unit 222. Hereinafter, the degree of attenuation of each attenuator (g _i (i = 0, 1, 2, ..., N-1) is defined as a weight g _i (i = 0,1,2 ..., N-1). The values of the weights may have one of magnitude, magnitude and phase, actual values, or complex values. In the following explanation, it is assumed that the weights have a magnitude or a real value for convenience.

The signal combiner 221 combines the output signals of the plurality of attenuators g ₀ to g _N-1 .

The control unit 222 variably sets the weights g ₀ to g _N-1 . The control unit 222 inputs the baseband equivalent frequency information Y (k) of the baseband equivalent frequency information X (k) of the transmission signal x (t) and the baseband equivalent frequency information Y (t) of the self transmission interference signal y And calculates a weight value g _i (i = 0,1,2, ..., N-1) using X (k) and Y (k), where k denotes a subcarrier index. _{(g i (i = 0,1,2 ...} , will be described in detail below for how to obtain the N-1).

The X (k) setting unit 223 sets the baseband equivalent frequency information X (k) of the transmission signal x (t). The method by which the X (k) setting unit 223 sets X (k) will be described in detail below.

On the other hand, the Y (k) setting unit 224 sets the baseband equivalent frequency information Y (k) of the self transmission interference signal y (t). A method of setting the Y (k) setting unit 223 to Y (k) will be described in detail below.

A method for the control unit 222 to obtain the weights g _i (i = 0, 1, 2, ..., N-1) will be described below.

As shown in Equation (1) below, the control unit 222 controls the weighting unit 220 so as to minimize the mean squared error (MSE) between the magnetic transmission interference signal y (t) and the output signal of the FIR filter 220 .

It is difficult to obtain the weight values g _i (i = 0, 1, 2, ..., N-1) of the time domain as shown in Equation 1. Therefore, Equation 1 can be converted into a frequency domain (frequency response) Equation (1) is transformed into the frequency domain as shown in Equation (2) below.

The algorithm for obtaining the actual weight by applying the concept of Equation (2) is as follows.

First, a vector and an error signal are defined as shown in the following equations (3) to (5).

Equation 3 assumes that the weight value g _i (i = 0,1,2, ..., N-1) is a vector and that the weight has only a magnitude value. Means a vector for the baseband equivalent frequency information X (k), i.e., the frequency response of x (t), of the input x (t) and the tap delay d _i , and k denotes a subcarrier index. Equation (5) represents the frequency response of Y (k) (i.e., y (t)) and the output signal of FIR filter 220

, And H denotes a symbol for transposing and conjugating.

One of the optimal methods for determining the weights is to obtain a g vector that minimizes the MSE (Mean Squared Error) of e (k) as shown in Equation (6) below. As shown in Equation (6) below,

.

Next, as shown in Equation (7) below,

Is obtained.

In Equation (7)

Wow

to be. Since Equation (7) concaves about the g vector, g, which makes the differential with respect to g zeor, becomes the optimum weight. If we summarize it as an equation, g _opt, which is the optimum weight, is obtained as follows.

In Equation (8), the statistical formula of R _xx and R _xy is not known. However, it is possible to take an average from the samples of X (k) and Y (k) and to estimate it as in the following equations (9) and (10).

In Equations (9) and (10), s denotes an index of a time domain symbol, and M 'denotes the total number of subcarriers available in all M channels. And the condition approximated by equation (9-2) in equation (9-1)

And the remaining components (i.e., the product vector of the vectors of Equation (9-1)).

From the above equations (9) and (10), the estimated

Is expressed by the following Equation (11).

Applying Equation (9-1)

Is expressed as Equation (11-1), and Equation (9-2)

Is expressed by Equation (11-2). Using Equation (11-2), the inverse matrix calculation amount of the matrix can be reduced stably. More specifically,

Is a predetermined inverse matrix, it is only necessary to update a value that does not require inverse matrix calculation. If you use a signal that you already know when you get a,

Is predetermined.

When the preamble of the WiFi system is used to obtain X (k) and Y (k) information in obtaining the weight, other subcarriers excluding the guarded subcarriers of the preamble can be applied to Equations (9) and have. When a pilot of an LTE (Long Term Evolution) system is used to acquire X (k) and Y (k) information, only pilot subcarriers can be applied to Equations (9) and (10). When a data signal including a pilot of the LTE system is used to obtain X (k) and Y (k) information, all the subcarriers to which the data signal is allocated can be applied to Equations (9) and (10).

Hereinafter, a method for estimating input information necessary to obtain Equations (3) to (11) will be described.

First, a method for estimating a delay value for each of the plurality of delay units (d ₀ to d _N-1 ) will be described.

In the analog circuit region, a delay (i.e., d _i ) is generated using a delay line. Even if a delay line is implemented to have a desired delay value, an error may occur in a desired delay value and an implemented delay value. When the weights of Equation (11) are obtained using delay values that do not compensate for this error, the SIC gain may be lowered. Therefore, the delay value applied to Equation (11) needs to be a delay value actually implemented. To this end, a delay value is estimated by a delay measuring device at a time of implementation or periodically on a manufactured product.

Next, a method of estimating (setting) X (k) (that is, the equivalent frequency information of the transmission band of the transmission signal x (t) or the frequency response of the transmission signal x (t)) will be described. That is, a method of estimating X (k) set by the X (k) setting unit 223 will be described.

FIG. 3 is a conceptual diagram illustrating a method of estimating X (k) in the same-band full duplex transceiver 100 of FIG.

3, the transmission signal x (t) is passed to the LNA 180, the integrator 190 and the ADC 200 of the reception module. At this time, the transmission signal x (t) Is directly input to the LNA 180 without passing through the FIR filter 220. The transmission signal passed through the ADC 200 becomes a signal sampled in the digital domain and the digital signal processing unit 210 converts the sampled signal into M- the sum of the M subcarriers generated through the FFT is equal to or similar to the system bandwidth. Here, the sum of the transmission signals x (k) used for estimation is X (k) (t) may be a training signal already known to all UEs, such as a preamble of WiFi or a pilot reference signal of LTE, Upon implementation of the full duplex transceiver 100, either once or periodically on the manufactured product 3. The estimated X (k) is set in the X (k) setting unit 223. The X (k)

Finally, a method of estimating (setting) Y (k) (that is, the baseband equivalent frequency information of the magnetic transmission interference signal y (t) or the frequency response of the magnetic transmission interference signal y (t)) will be described. That is, a method of estimating Y (k) set by the Y (k) setting unit 224 will be described.

FIG. 4 is a conceptual diagram illustrating a method of estimating Y (k) in the same-band full duplex transceiver 100 of FIG.

As shown by the dotted line in Fig. 4, the transmission signal x (t) is input to the reception module, and this incoming signal corresponds to the self-transmission interference signal y (t). At this time, the transmission signal x (t) is not input to the FIR filter 220. And passes this self-transmitted interference signal y (t) to the LNA 180, the integration 190 and the ADC 200. The digital signal processor 210 performs a M-point Fast Fourier Transform (FFT) on the sampled signal to obtain a final resultant signal y (t) (K). On the other hand, when estimating Y (k), it is necessary to use modules (i.e., LNA, integrator, and ADC) used in estimating X (k). This makes it possible to prevent SIC deterioration that may occur when the hardware submodule is different. Here, the transmission signal x (t) used for estimation can be a training signal already known to all the terminals, such as a preamble of WiFi or a pilot reference signal of LTE have. This Y (k) can be estimated as shown in Fig. 4 whenever the weights are updated. The estimated Y (k) is set in the Y (k) setting unit 224. [

Meanwhile, the interference cancellation method of the same-band full duplex transceiver 100 according to the embodiment of the present invention described above is summarized in FIG.

5 is a flowchart illustrating an interference cancellation method of the same-band full duplex transceiver 100 according to an embodiment of the present invention.

First, a tap delay value, X (k), and Y (k) are estimated (S510). As described above, the delay value per tap is realized through the delay line and is estimated periodically at the time of manufacture or on the manufactured product. Then, X (k) is estimated as described in Fig. 3, and Y (k) is estimated as described in Fig.

The tab-specific delay (delay) value estimated in step S510, X (k), using the Y (k), obtained by the tap weights _{(g i (i = 0,1,2 ...} , N-1) (S520 ) At this time, the optimized weight can be obtained by applying Equation (11).

The weight obtained in step S520 is applied to the FIR filter 220 (S530). That is, the control unit 222 applies the optimized weight to each attenuator.

The signal combiner 170 finally performs a mathematical subtraction between the self-transmission interference signal and the output signal of the FIR filter 220 (S540). That is, by subtracting the output signal of the FIR filter 220 from the self-transmitted interference signal, the self-transmitted interference signal can be removed.

FIG. 6 is a diagram illustrating a same-band full duplex transceiver 100 'in accordance with another embodiment of the present invention.

6, the same-band full duplex transceiver 100 'according to another embodiment of the present invention includes a digital signal generator 110, a digital-analog converter (DAC) 120, a mixer A power amplifier (PA) 140, a distributor 150 ', an antenna 160, a first signal combiner 170', a second signal combiner 170 '', a low noise amplifier An integrator 190, an analog-to-digital converter (ADC) 200, a digital signal processor 210 and an FIR (Finite Impulse Response) filter 220 ' . The same-band full duplex transceiver 100 'of FIG. 6 is similar to the same-band full duplex transceiver 100 of FIG. 1 except that the distributor 150' is implemented as an EBD and two signal combiners 170 ', 170 " . Therefore, redundant description is omitted.

The distributor 150 'includes a hybrid transformer 151 and a balance network 152. The hybrid transformer 151 branches the transmission signal x (t) to the antenna 160 and the balance network 152. A signal corresponding to a signal at the rear end of the PA 140 or a transmission signal of the antenna 160 is output to a contact point (hereinafter referred to as a balance point) of the hybrid transformer 151 and the balance network 152 do. That is, since the transmission signal is also output to the balance point BP, it is represented by x (t) in Fig. Meanwhile, the balance network 152 is constituted by a passive element and serves to control the impedance flowing to the antenna 160 and the impedance flowing to the end of the balance network 152 in the same manner. The reception signal received from the antenna 160 is separated and inverted in phase by the hybrid transformer 151, and the separated reception signals are outputted to the reception output terminal Rx1 and the reception output terminal Rx2, respectively. The specific structure of the hybrid transformer 151 and the balance network 152 is known to those skilled in the art, so that detailed description thereof will be omitted.

When the distributor 150 'is implemented as an EBD, it is possible to prevent the transmission signal from flowing into the receiving module (LNA or the like), but a part of the transmitting signal may be introduced into the receiving module. The self-transmit interference signal introduced into the receiving module may be removed by the FIR filter 220 as described above.

The first signal combiner 170 'combines the reception signals output from the reception output Rx1 and the reception output Rx2. At this time, since the reception signal output from the reception output terminal Rx1 and the reception signal of the reception output terminal Rx2 are in opposite phase to each other, the first signal combiner 170 ' (Rx2), and combines the two signals.

The structure of the FIR filter 220 'of FIG. 6 is the same as that of the FIR filter 220 of FIG. 1, but there is one difference. The FIR filter 220 of FIG. 1 receives the transmission signal of the rear end of the PA 140, while the FIR filter 220 'of FIG. 6 receives the signal of the balance point BP. The algorithm for obtaining the weight of the FIR filter 220 'is the same as that of Equations 3 to 11, which is an algorithm for obtaining the weight of the FIR filter 220 described above.

Hereinafter, a method for estimating input information required to obtain a weight in the same-band full duplex transceiver 100 'according to another embodiment of the present invention will be described.

The method of estimating the delay value of each of the plurality of delay units (d ₀ to d _N-1 ) is the same as the above-described method, and a detailed description thereof will be omitted.

Next, a method of estimating (setting) X (k) (that is, the equivalent frequency information of the transmission band of the transmission signal x (t) or the frequency response of the transmission signal x (t)) will be described.

FIG. 7 is a conceptual diagram illustrating a method for estimating X (k) in the same-band full duplex transceiver 100 'of FIG.

Passes the transmission signal x (t) to the LNA 180, the integrator 190 and the ADC 200 of the reception module, as indicated by the dotted line in Fig. At this time, the transmission signal x (t) is directly input to the LNA 180 without passing through the FIR filter 220 'and the second signal combiner 170' '. The transmission signal passed through the ADC 200 is a signal sampled in the digital domain, and the digital signal processing unit 210 finally performs X-axis estimation by performing an M-point Fast Fourier Transform (FFT) on the sampled signal . Here, the sum of the M subcarriers generated through the FFT is equal to or similar to the system bandwidth. Here, the transmission signal x (t) used for estimation can be a training signal already known to all the terminals, such as a preamble of WiFi or a pilot reference signal of LTE have. This X (k) may be estimated once in the implementation of the same-band full duplex transceiver 100 'or periodically on the manufactured product as shown in FIG. The estimated X (k) is set in the X (k) setting unit 223. [

A method of estimating (setting) Y (k) (that is, the baseband equivalent frequency information of the magnetic transmission interference signal y (t) or the frequency response of the magnetic transmission interference signal y (t)) will be described. That is, a method of estimating Y (k) set by the Y (k) setting unit 224 will be described.

FIG. 8 is a conceptual diagram illustrating a method of estimating Y (k) in the same-band full duplex transceiver 100 'of FIG.

8, the transmission signal x (t) is input to the reception module via the hybrid transformer 151, and this incoming signal corresponds to the self-transmission interference signal y (t). At this time, the transmission signal x (t) is not input to the FIR filter 220 '. And passes this self-transmitted interference signal y (t) to the LNA 180, the integration 190 and the ADC 200. The digital signal processor 210 performs a M-point Fast Fourier Transform (FFT) on the sampled signal to obtain a final resultant signal y (t) (K). On the other hand, when estimating Y (k), it is necessary to use modules (i.e., LNA, integrator, and ADC) used in estimating X (k). This makes it possible to prevent SIC deterioration that may occur when the hardware submodule is different. Here, the transmission signal x (t) used for estimation can be a training signal already known to all the terminals, such as a preamble of WiFi or a pilot reference signal of LTE have. This Y (k) can be estimated as shown in FIG. 8 every time the weight is updated. The estimated Y (k) is set in the Y (k) setting unit 224. [

The interference cancellation method of the same-band full duplex transceiver 100 'according to another embodiment of the present invention described above is summarized in FIG.

9 is a flowchart illustrating a method of canceling interference of a same-band full duplex transceiver according to another embodiment of the present invention.

First, a tap delay value, X (k), and Y (k) are estimated (S910). As described above, the delay value per tap is realized through the delay line and is estimated periodically at the time of manufacture or on the manufactured product. Then, X (k) is estimated as described in Fig. 7, and Y (k) is estimated as described in Fig.

Using a tab-specific delay (delay) value, X (k), Y ( k) estimated in step S910, the tap-specific weight _{(g i (i = 0,1,2 ...} , is obtained for N-1) (S920 ) At this time, the optimized weight can be obtained by applying Equation (11).

The weight obtained in step S920 is applied to the FIR filter 220 '(S930). That is, the control unit 222 applies the optimized weight to each attenuator.

The second signal combiner 170 " finally performs a mathematical subtraction between the magnetic transmission interfering signal and the output signal of the FIR filter 220 '(S940). That is, by subtracting the output signal of the FIR filter 220 'from the self-transmitted interference signal, the self-transmitted interference signal can be removed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (18)

antenna,
A distributor for transmitting a transmission signal to the antenna and for transmitting a reception signal received through the antenna to a reception module via a reception output terminal,
And second information that is baseband equivalent frequency information of a self-transmission interference signal included in a signal output from the reception output terminal, the first information being baseband equivalent frequency information of the transmission signal, And a finite impulse response (FIR) filter for removing the magnetic transmission interference signal
The same - band full duplex transceiver. The method according to claim 1,
The FIR filter includes:
A plurality of delay units for receiving and delaying the transmission signals,
A plurality of attenuators connected to the plurality of retarders and attenuating the signals,
A signal combiner for combining the output signals of the plurality of attenuators, and
And a controller for setting the degree of attenuation of the plurality of attenuators so as to eliminate the magnetic transmission interference signal
The same - band full duplex transceiver. 3. The method of claim 2,
And the controller sets the degree of attenuation using the first information and the second information
The same - band full duplex transceiver. The method of claim 3,
Wherein the delay of the plurality of delay units is fixed. The method according to claim 1,
A power amplifier for outputting the transmission signal, and
And a signal combiner for combining a signal output from the reception output terminal and a signal output from the FIR filter,
Wherein the FIR filter is located between the power amplifier and the signal combiner
The same - band full duplex transceiver. 3. The method of claim 2,
Wherein the controller sets the degree of attenuation to minimize a mean square error between the magnetic transmission interfering signal and the output signal of the FIR filter
The same - band full duplex transceiver. 3. The method of claim 2,
The receiving module includes a low noise amplifier, an integrator, and an analog-to-digital converter for converting the output of the integrator into a digital signal,
The first information may be a signal obtained by passing the transmission signal through the amplifier, the integrator, and the analog-digital converter and then performing a Fast Fourier Transform (Fast Fourier Transform)
The same - band full duplex transceiver. 8. The method of claim 7,
The second information may be a signal obtained by passing through the amplifier, the integrator, and the analog-to-digital converter and then performing a fast Fourier transform (Fast Fourier Transform)
The same - band full duplex transceiver. antenna,
And a first output terminal for outputting a first signal which is a signal corresponding to the transmission signal, and a second output terminal for transmitting a transmission signal to the antenna, Splitter, and
The first information being frequency response information of the transmission signal and the second information being frequency response information of a self transmission interference signal included in a signal output from the reception output terminal, A Finite Impulse Response (FIR) filter for removing the interference signal
The same - band full duplex transceiver. 10. The method of claim 9,
Wherein the distributor comprises:
A hybrid transformer for transmitting the transmission signal to the antenna and for transmitting the reception signal to the reception module,
And a balance network connected to the hybrid transformer for controlling an impedance corresponding to an impedance flowing to the antenna,
Wherein the first signal is a signal output to a contact of the hybrid transformer and the balance network. 10. The method of claim 9,
The FIR filter includes:
A plurality of delay units for receiving and delaying the first signals,
A plurality of attenuators connected to the plurality of retarders and attenuating the signals,
A signal combiner for combining the output signals of the plurality of attenuators, and
And a controller for setting the degree of attenuation of the plurality of attenuators so as to eliminate the magnetic transmission interference signal,
And the controller sets the degree of attenuation using the first information and the second information
The same - band full duplex transceiver. 11. The method of claim 10,
Wherein the reception output stage includes a first reception output stage and a second reception output stage,
Wherein the second signal output from the first reception output terminal and the third signal output from the second reception output terminal are signals whose phases are inverted from each other. 13. The method of claim 12,
A first signal combiner for combining the second signal and the third signal,
And a second signal combiner for combining the output of the first signal combiner and the output of the FIR filter and outputting the combined signal to the receiving module,
Wherein the FIR filter is located between the contact and the second signal combiner
The same - band full duplex transceiver. 10. The method of claim 9,
The receiving module includes a low noise amplifier, an integrator, and an analog-to-digital converter for converting the output of the integrator into a digital signal,
The first information may be a signal obtained by passing the transmission signal through the amplifier, the integrator, and the analog-digital converter and then performing a Fast Fourier Transform (Fast Fourier Transform)
The same - band full duplex transceiver. 15. The method of claim 14,
The second information may be a signal obtained by passing through the amplifier, the integrator, and the analog-to-digital converter and then performing a fast Fourier transform (Fast Fourier Transform)
The same - band full duplex transceiver. A duplex transceiver for removing interference from a same-band full duplex transceiver comprising an antenna and a divider for sending a transmission signal through the antenna and for sending a received signal received via the antenna to a receiving module,
Generating first information that is baseband equivalent frequency information of the transmission signal,
Generating second information that is baseband equivalent frequency information of a self-transmission interference signal generated in the receiving module by the transmission signal, and
And using the first information and the second information to remove the self-transmitted interference signal. 17. The method of claim 16,
Wherein the removing comprises:
Delaying the transmission signal,
Attenuating the delayed transmission signal using the first information and the second information, and
And combining the attenuated transmission signal
Interference cancellation method. 18. The method of claim 17,
Wherein the removing further comprises subtracting the attenuated transmission signal from the magnetic transmission interfering signal
Interference cancellation method.

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