KR20170025966A - Analog self interference cancellation system in ofdm-based wireless communication system - Google Patents

Abstract

The present invention relates to an analog self-interference cancellation system in an OFDM-based wireless communication system. The analog self-interference cancellation system includes: a transmitter for generating a transmission signal using a baseband input signal and transmitting the generated transmission signal through wireless communication; a self-interference signal generator for generating a pseudo self-interference signal using the baseband input signal; and a receiver for receiving the transmission signal transmitted from the transmitter through wireless communication and the pseudo self-interference signal from the self-interference signal generator, wherein the receiver removes the self-interference signal included in the transmission signal by using the pseudo self-interference signal to extract a signal from which the self-interference signal included in the transmission signal is removed. The self-interference signal included in the transmission signal received by the receiver is a self-interference signal which is generated by forming the transmission signal as a multi-channel signal when the receiver receives the transmission signal transmitted from the transmitter through wireless communication. Therefore, a baseband self-interference signal estimation and generation unit of a transmitting end adds a delay and a weight to the baseband signal of the transmitting end to estimate the self-interference signal and generate the pseudo self-interference signal, thereby generating the self-interference signal for a multi-path channel without adding adding a hardware configuration.

Description

Technical Field [0001] The present invention relates to an analog magnetic interference cancellation system in an OFDM-based wireless communication system,

The present invention relates to an analog magnetic interference cancellation system in an OFDM based wireless communication system.

BACKGROUND OF THE INVENTION [0002] Wireless communication systems based on Orthogonal Frequency Division Multiplexing (OFDM), in particular, full duplex wireless communication systems that perform bidirectional communication, suffer from magnetic interference.

Magnetic interference is generated by different paths in a wireless channel by multipath. When a signal transmitted from a transmitter is received by a receiver, a transmission signal of the transmitter is generated by magnetic interference.

In order to eliminate such magnetic interference, the transmitter generates the same signal as the transmission signal and transmits it as a magnetic interference cancellation signal, and the receiver receives the magnetic interference cancellation signal to remove magnetic interference.

As an example, Korean Patent Laid-Open No. 10-2010-0021383 discloses a method for removing magnetic interference of the same frequency relay and a repeater in an OFDM-based wireless communication system and an apparatus therefor.

However, since a device for removing magnetic interference through such a method has a structure for adding a delay to an RF signal after upconversion and generating a pseudo interference signal by forming an attenuator, There is a limitation in that it is difficult to configure the hardware according to the hardware.

In addition, the attenuator can not be estimated in multiple, and there is a limit in that it can not efficiently remove the magnetic interference to the multipath radio channel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a magnetic interference cancellation system which applies a multi-path channel at a base band stage and estimates a signal of a different path by applying a weight to each delay, Simplify the configuration, and reduce the cost required for the configuration.

An analog magnetic interference cancellation system in an OFDM-based wireless communication system according to an embodiment of the present invention includes a transmitter that generates a transmission signal using a baseband input signal and transmits the generated transmission signal through wireless communication, Band interference signal to generate a pseudo-magnetic interference signal; and a transmission unit that receives the transmission signal transmitted from the transmission unit through wireless communication, and receives the pseudo-magnetic interference signal from the magnetic interference signal generation unit And extracting a signal from which the magnetic interference signal included in the transmission signal is removed from the transmission signal by removing the magnetic interference signal included in the transmission signal using the pseudo magnetic interference signal, And a reception unit for extracting the transmission signal, The interference signal is a magnetic interference signal generated by forming the transmission signal into a multi-channel signal when the reception unit receives the transmission signal transmitted from the transmission unit through wireless communication.

The magnetic interference signal generator includes a delay adding unit for adding the baseband input signal to a subcarrier and adding a delay, and an attenuator for multiplying a variable-attenuated value by a signal modulated by the subcarrier and delayed by the delay adding unit , And the delay adding unit is performed through the following Equation (1).

[Formula 1]

는 M번째 딜레이,

는 M번째 딜레이(

)가 추가된 M번째 신호,

는 k번째 서브캐리어의 주파수, 그리고

는 기저대역 입력신호를 각각 나타냄.Here, M is the number of channels as a natural number of 1 or more,

Is an Mth delay,

Is an Mth delay (

) Is added to the Mth signal,

Is the frequency of the kth subcarrier, and

Respectively represent baseband input signals.

In one example, the delay adding unit of the magnetic interference signal generating unit modulates each baseband input signal for a plurality of channels forming the baseband input signal by subcarriers and adds a delay, and the attenuator adds the delay adding And multiplies the respective baseband input signals for the plurality of channels modulated by the subcarriers in the subcarrier and added with the delay by the attenuation value.

Wherein the magnetic interference signal generation unit generates a magnetic interference signal by combining the baseband input signals for the plurality of channels multiplied by the attenuation values in the attenuation unit by adding modulation and delay to the subcarriers in the delay adding unit, And the merging unit is performed through the following equation (2).

[Formula 2]

는 병합부의 출력신호,

는 가변 감쇄값, 그리고

는 기저대역 입력신호를 각각 나타냄.here,

The output signal of the merging unit,

A variable attenuation value, and

Respectively represent baseband input signals.

And a phase changing unit for changing the phase of the output signal generated by the merging unit.

The delay adding unit adds an equal delay to each of the baseband input signals for the plurality of channels forming the baseband input signal.

Wherein the delay adding unit adjusts the delay values by assigning different weights to the respective baseband input signals for the plurality of channels forming the baseband input signal.

The transmitter includes a first OFDM modulator for OFDM modulating an input signal of the baseband, a first DAC for converting an OFDM modulated signal in the first OFDM modulator into an analog signal, And a first frequency conversion unit for frequency up-converting the converted signal.

Wherein the magnetic interference signal generator is configured to form the delay adding unit, the attenuator, the merging unit, and the phase changing unit as a baseband magnetic interference signal estimating and generating unit, and the phase varying unit A second DAC for converting a signal modulated by the second OFDM modulator into an analog signal, a second DAC for converting a signal converted into an analog signal in the second DAC into a frequency And an RF amplifier for amplifying a frequency up-converted signal from the second frequency converter to a signal of a wireless communication band.

The receiver may further include: a third frequency converter for frequency downconverting a signal from which the magnetic interference signal included in the transmission signal is removed; an ADC for converting the frequency downconverted signal from the third frequency converter into a digital signal; And a demodulator for extracting the baseband input signal from the signal converted into the digital signal by the ADC.

According to this aspect, the baseband magnetic interference signal estimator and generator of the transmitter generates the pseudo-magnetic interference signal by estimating the magnetic interference signal by adding the delay and the weight to the baseband signal of the transmitter, It is possible to generate the magnetic interference signal for the multi-path channel without adding the < RTI ID = 0.0 >

1 is a block diagram illustrating a structure of an analog magnetic interference cancellation system in an OFDM-based wireless communication system according to an embodiment of the present invention.
2 is a diagram illustrating a structure of a baseband magnetic interference signal estimation and generator in an analog magnetic interference cancellation system in an OFDM-based wireless communication system according to an embodiment of the present invention.
FIG. 3 is a graph illustrating a simulation of a self interference cancellation performance according to a sub-carrier according to a path of a simulated magnetic interference channel in an OFDM-based wireless communication system 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 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.

Hereinafter, an analog magnetic interference cancellation system in an OFDM-based wireless communication system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1, a structure of an analog magnetic interference cancellation system in an OFDM-based wireless communication system according to an embodiment of the present invention includes a transmitter 10, a magnetic interference signal generator 20, and a receiver 30 ).

The transmitter 10 includes a first OFDM modulator 11, a first DAC 12 and a first frequency converter 13 to generate an input signal x _k as x (t) do.

The first OFDM modulator 11 modulates the input signal x _k by orthogonal frequency division multiplexing (OFDM) and outputs it as a signal in the time domain.

At this time, when the input signal x _k has a plurality of channels, the first OFDM modulator 11 modulates and outputs the input signals x _k of the respective channels.

A first digital-to-analog converter (DAC) 12 receives a digital signal, which is a modulated signal output from the first OFDM modulator 11, and converts the digital signal into an analog signal.

The first frequency converter 13 receives the modulated signal, which is a signal converted into an analog signal in the first DAC 12, and performs frequency up conversion, that is, up conversion.

Since the signal output from the first DAC 12 and processed by the first frequency converter 13 is a baseband signal, the first frequency converter 13 converts the baseband signal into a set frequency, In the embodiment of the present invention, the first frequency converter 13 up-converts the baseband signal into a frequency band capable of wireless communication and outputs the up-converted frequency band signal.

A signal up-converted to a frequency band capable of radio communication in the first frequency conversion unit 13 is wirelessly transmitted through an antenna.

The magnetic interference signal generator 20 includes a baseband magnetic interference signal estimator and generator 21, a second OFDM modulator 22, a second DAC 23, a second frequency converter 24, And an amplifier 25.

At this time, the baseband magnetic interference signal estimator and generator 21 estimates and generates a magnetic interference signal using x _k , which is an input signal input to the first OFDM modulation unit 11 of the transmitter 10, and generates an input signal x _{When k} has a plurality of channels, a magnetic interference signal is generated by estimating a magnetic interference signal using an input signal x _k of each channel.

The magnetic interference signal generated by the baseband magnetic interference signal estimator and generator 21 is a signal y (t) having a plurality of channels when x (t) transmitted from the transmitter 10 is received by the receiver 30 as y (t) is the same signal as the magnetic interference signal generated by the multipath channel.

More specifically, since the magnetic interference signal generated in the signal y (t) received by the receiver 30 is a magnetic interference signal generated based on the signal x (t) transmitted from the transmitter 10, the baseband magnetic interference And the generator 21 estimate the magnetic interference signal from the input signal x _{k on} which the signal x (t) of the transmitter 10 is based, and outputs the estimated magnetic interference signal as a pseudo magnetic interference signal.

In this case, k is an index of a subcarrier on which the input signal is carried, and x _k is a baseband transmission signal on the kth subcarrier.

로 표현되며, 이때, K는 고속 퓨리에 변환(FFT)의 사이즈이다.Therefore, the signal x (t) of the transmission unit 10 is obtained from the input signal x _k

, Where K is the size of the Fast Fourier Transform (FFT).

Therefore, the baseband magnetic interference signal estimator and generator 21 estimates the magnetic interference signal from the input signal x _k and generates and outputs a pseudo-magnetic interference signal.

2, the baseband magnetic interference signal estimator and generator 21 includes a plurality of delay adding units 211 and 213, a delay adding unit 212, Attenuators 212 and 214 for attenuating the signals output from the first and second antennas 211 and 213, a signal merge unit 215, and a phase change unit 216.

The plurality of delay adding units 211 and 213 add the delays by dividing the signal x _k having the plurality of channels input to the baseband magnetic interference signal estimating and generating unit 21 into respective channels, The signal x _k for the channel is loaded on a subcarrier.

At this time, the delays added by the delay adding units 211 and 213 may be added to the respective channels with different delay values.

However, in one example, the delays to be added by the delay adding units 211 and 213 are added as the same delay value, and different weights assigned to the respective delays are applied to different delays of different channels to give different weights , And finally, the value of the delay added to each channel can be adjusted.

At this time, the signal reflecting the delay in the signal x _k of each channel is expressed by the following Equation 1.

[Formula 1]

는 M번째 딜레이,

는 M번째 딜레이(

)가 추가된 M번째 신호, 그리고

는 k번째 서브캐리어의 주파수를 각각 나타낸다.In Equation (1), M is the number of channels as a natural number of 1 or more,

Is an Mth delay,

Is an Mth delay (

) Is added to the Mth signal, and

Represents the frequency of the k-th subcarrier.

The delay adders 211 and 213 modulate the delay-added signals by placing them on the subcarriers.

The attenuation units 212 and 214 multiply the variable modulated signal by a delay added by the delay adding units 211 and 213 and modulated on the subcarriers.

는 M개의 각 채널에 대한 M개의 부반송파 에 곱해지는 값으로,

에서

에 이르는 M개의 가변 감쇄값으로서 각각의 부반송파에 곱해진다.The variable attenuation values multiplied by the attenuation sections 212 and 214

Is a value multiplied by M subcarriers for each of M channels,

in

And the subcarriers are multiplied by M variable attenuation values.

와 각 채널의 크기

는 L개의 자기 간섭 채널에서 각각의 다중 경로의 딜레이가

이고 채널의 크기가

인 L개의 다중 경로를 갖는 자기 간섭 채널을 유추하기 위해 가정된 유사 채널로서, 본 발명에서는 유사 채널의 딜레이와 각 채널의 크기를 실제 다중경로 자기간섭 채널의 딜레이 및 채널의 크기와 동일하게 하는

및

를 구하는 것을 목표로 한다.At this time, the delay for M channels

And the size of each channel

Lt; RTI ID = 0.0 > L < / RTI >

And the size of the channel is

In the present invention, the delay of the similar channel and the size of each channel are made equal to the delay and channel size of the actual multipath magnetic interference channel

And

.

는 다음의 식 2와 같다.That is, an actual magnetic interference signal, which is an output signal that has passed through an actual magnetic interference channel having L multipath channels, is added to the input signal x _k

Is expressed by the following equation (2).

[Formula 2]

However, the output signal passed through the similar channel assumed by the delay adding units 211 and 213 is expressed by the following Equation 3, which is a form in which the similar magnetic interference signal is added to the input signal x _k .

[Formula 3]

및

를 사용하여 가정된 유사 채널에서 발생하는 유사 자기간섭 신호로, 의사 자기간섭 신호이다.At this time, the similar magnetic interference signal

And

Is a pseudo-magnetic interference signal generated in a pseudo-channel hypothesized using the pseudo-magnetic interference signal.

를 얻으며, 이러한 병합과정은 병합부(215)에서 수행된다.Thus, in Equation 3, a plurality of channels added with a delay and multiplied by a variable attenuation value are combined

And the merging process is performed in the merging unit 215. [

는 유사 채널을 통과한 출력신호로서, 의사 자기간섭 신호가 입력신호 x_k에 추가된 신호이고, M과 L은 같은 값이 아닐 수 있다.In the above equation 3,

Is an output signal that passes through a pseudo-channel, where the pseudo-magnetic interference signal is a signal added to the input signal x _k , and M and L may not be the same value.

가 식 2의

와 유사한 값을 형성하기 위해 각 채널에 추가하는 딜레이의 값은 단일 값으로서 적용하되, 유사 채널의 경로 크기는 가변 감쇄값인

를 적용한다.As already described above, the delay adding units 211 and 213 have Equation (3)

Equation 2

The value of the delay added to each channel to form a similar value is applied as a single value, and the path size of the pseudo channel is a variable attenuation value

Is applied.

은 복소수 형태이다.In one example, the variable attenuation value

Is a complex number form.

는

이고, 각 경로의 크기가

인 경우를 유추하기 위한 유사 채널의 고정 딜레이 값과 가변 감쇄값의 한 예를 설명하면, 실제 자기간섭 채널의 경로 개수(L=5)를 모르는 본 발명의 딜레이 추가부(211, 213)는 유사 채널을 유추하기 위해서 M을 4로 설정하고 다음과 같이 고정 딜레이를 설정한다.In an actual magnetic interference channel with five multipaths, the delay for each channel

The

, And the size of each path is

The delay adders 211 and 213 of the present invention, which do not know the number of paths (L = 5) of the actual magnetic interference channel, are similar to the delay adders 211 and 213 of the present invention, To infer the channel, set M to 4 and set the fixed delay as follows.

At this time, when the SNR of the channel is 30 dB, the attenuators 212 and 214 multiply each channel of the similar channel by the variable attenuation value () using the following Equation (4).

[Formula 4]

는

의 합의 행렬이고,

는

의 복합공액전치행렬,

는

의 항등행렬,

은 모든 k에 대한

의 합이고, 이때, 는 기저대역 수신신호인 k번째 부반송파에서의 기저대역 수신신호로서, 다음의 식 5로부터 산출된다.In the above equation 4,

The

≪ / RTI >

The

A complex conjugate transpose matrix,

The

The identity matrix,

For all k

, Where is the baseband received signal at the kth subcarrier, which is the baseband received signal, and is calculated from Equation 5 below.

[Formula 5]

는 위의 식 3에서 얻은

를 A로 나누어 산출한 값으로서, 이때, A는 고정 RF 감쇄값이고,

는 k 번째 부반송파에 추가된 백색잡음값이다.In equation 5 above,

Lt; RTI ID = 0.0 >

Is a value calculated by dividing by A, where A is a fixed RF attenuation value,

Is the white noise value added to the k-th subcarrier.

를 계산한다.At this time, the OFDM system assumed in the present invention is designed as a full-duplex communication and operates in a training mode and a data transmission / reception mode. In the training mode, since a counterpart does not transmit data and only a magnetic interference signal is received at a receiver, Mode from the magnetic interference signal, which is the reception signal of the mode,

.

In the data transmission / reception mode, a delay value fixed to the calculated variable attenuation value is applied in the training mode to generate a similar magnetic interference signal, thereby removing the magnetic interference signal received by the receiver.

In this case, as shown in Equation (5), by applying the fixed attenuation value A to the received signal, since the transmitting antenna and the receiving antenna are formed close to each other in the full-duplex communication, the magnetic interference signal received by the receiver in the training mode becomes the dynamic range it is difficult to ADC the RF signal which is a magnetic interference signal received in excess of the dynamic range.

를 계산한다.That is, the receiver can perform the ADC processing on the magnetic interference signal by performing the RF attenuation applying the fixed attenuation value A to all the subcarriers. In this case, the receiver receives the training attenuation value, applies the positive attenuation value A, 5 < / RTI >

.

At this time, since the similar magnetic interference signal generated in the data transmission / reception mode is smaller than the actual magnetic interference signal by the fixed attenuation value A, the RF amplifier 25 is used to correct the similar magnetic interference signal to RF Amplified.

Therefore, in the case where M is 4, the variable attenuation values derived by the attenuators 212 and 214 using the above Equation 4 are as follows.

In this case, the generated variable attenuation value is multiplied by each channel to form a pseudo magnetic interference channel. After passing through the RF amplifier 25 after DAC, the variable attenuation value is formed similar to an actual magnetic interference channel as shown in FIG. The actual magnetic interference signal can be efficiently removed using the interference signal.

3, when the M is set to 2, the magnetic interference cancellation performance of the magnetic interference channel is as follows. Only in the specific subcarrier portion (-300th subcarrier and 300th subcarrier) Performance is good, and magnetic interference cancellation performance deteriorates in the remaining subcarrier parts.

In addition, as shown in FIG. 3, the magnetic interference cancellation performance of the pseudo-magnetic interference channel when M is set to 4 and the magnetic interference cancellation performance of the pseudo-magnetic interference channel when M is set to 5 are similar to each other, From the simulation results shown, when the path of the similar magnetically interfering channel is 4 or more, the performance of removing the magnetic interference generated in the actual magnetic interference channel becomes higher.

(M = 4) smaller than the number of channels (L = 5) of the actual magnetic interference channel in the embodiment of the present invention. However, even if the number of channels in the similar coherent channel is smaller than the number of channels of the actual coherent channel The actual magnetically interfering channel is efficiently removed from the similar magnetically-interfering channel.

에

를 곱하여 위상을 변화시킨다.2, the phase shifting unit 216 shifts the phase of the signal output from the merging unit 215

on

To change the phase.

로 출력한다.As described with reference to FIG. 2, the baseband magnetic interference signal estimator and generator 21 modulates the input signal x _k for each channel and applies delay and attenuation values

.

Therefore, due to the structure of the baseband magnetic interference signal estimator and generator 21, the input signal x _k can be input to the input signal _xk in a form such that the delay is added and attenuated, similarly to the magnetic interference signal to be generated in the reception process of the receiver 30. [ .

를 제2 OFDM 변조부(22)에서 변조하고, 제2 DAC(23)에서 아날로그 신호로 변환하며, 제2 주파수 변환부(24)에서 주파수 변환하고, RF 증폭기(25)에서 증폭한다.The magnetic interference signal generator 20 including the baseband magnetic interference signal estimator and generator 21 receives the signal output from the magnetic interference signal estimator and generator 21

Is modulated by the second OFDM modulator 22 and is converted into an analog signal by the second DAC 23 and is frequency-converted by the second frequency converter 24 and amplified by the RF amplifier 25.

를 각 채널에 대해 변조하여 변조된 신호를 출력한다.At this time, similarly to the first OFDM modulator 11, the second OFDM modulator 22 modulates the signal output from the magnetic interference signal estimator and generator 21

Modulated for each channel to output a modulated signal.

The second DAC 23 converts the digital signal modulated and output by the second OFDM modulator 22 into an analog signal and outputs the converted analog signal.

The second frequency converter 24 frequency up-converts the analog signal output from the second DAC 23 and the RF amplifier 25 converts the frequency up-converted signal from the second DAC 23 And amplifies it with a communicable signal.

The configuration of the second OFDM modulator 22, the second DAC 23 and the second frequency converter 24 of the magnetic interference signal generator 20 is the same as the configuration of the first OFDM modulator 23 of the transmitter 10, The second DAC 11, the first DAC 12, and the first frequency converter 13, respectively.

However, in the case of the transmitting unit 10, the magnetic interference signal generating unit 20 does not include the antenna and transmits the signal output from the first frequency converting unit 13 through the transmitting antenna, The signal generated by the magnetic interference signal generator 20 is estimated and generated in the same manner as the magnetic interference signal generated by the receiver 30 because the signal generated by the magnetic interference signal generator 20 is directly transmitted to the receiver 30, An RF amplifier 25 is configured in the magnetic interference signal generator 20 to amplify the frequency-converted signal by the second frequency converter 24. [

를 RF 대역으로 증폭하여

를 생성함으로써, 자기간섭 신호 추정 및 생성기(21)는 최종적으로

를 출력하게 된다.Therefore, the magnetic interference signal estimator and generator 21 performs modulation and analog conversion on the signal obtained by estimating the magnetic interference signal using the input signal, and outputs the frequency up-converted signal

To the RF band

, The magnetic interference signal estimation and generator 21 finally generates

.

1, the receiving unit 30 includes a third frequency conversion unit 31, an ADC 32, and a demodulation unit 33. The third frequency conversion unit 31 receives Frequency downconverted signals.

에 의해 제거된다.At this time, the signal subjected to the frequency down conversion by the third frequency transforming unit 31 is a signal from which the magnetic interference is removed, and the magnetic interference signal included in the signal y (t) received by the receiving unit 30 is generated by the magnetic interference signal generating unit 20 and transmitted to the receiver 30,

Lt; / RTI >

는 위에서 이미 설명한 것처럼 자기간섭 신호 생성부(20)에서 입력신호 x(t)를 이용하여 수신부(30)에서 발생할 자기간섭을 추정하여 생성한 자기간섭 신호이므로, 자기간섭 신호가 발생한 수신신호인 y(t)는

에 의해 자기간섭 신호가 제거되고, 따라서, 제3 주파수 변환부(31)는 수신신호 y(t) 중 자기간섭 신호가 제거된 신호를 주파수 하향 변환하게 된다.More specifically, the signal y (t) received by the receiving unit 30 through the receiving antenna is received by the receiving unit 30 through the wireless communication through the transmitting unit 10, Is a signal added with magnetic interference caused by delay or attenuation in M channels forming the signal x (t) in the process,

Is a magnetic interference signal generated by estimating the magnetic interference generated in the receiving unit 30 by using the input signal x (t) in the magnetic interference signal generating unit 20 as described above, (t)

The third frequency converter 31 frequency downconverts the signal from which the magnetic interference signal has been removed from the received signal y (t).

에 의해 제거되며, 이때, 의사 자기간섭 신호는 기저 대역의 디지털 신호를 제어함으로써 생성되므로, 각 채널에 대한 딜레이를 서로 다르게 형성하는 것이 용이하다.As described above, the magnetic interference signal included in the reception signal y (t) received by the reception unit 30 is the quasi-magnetic interference signal generated by the magnetic interference signal generation unit 20

At this time, since the pseudo-magnetic interference signal is generated by controlling the baseband digital signal, it is easy to form delays for each channel differently.

Since the magnetic interference signal generator 20 of the present invention has such a structure, the pseudo-magnetic interference signal can be easily generated, and the cost for the structure for generating magnetic interference can be reduced.

1, the structure of the receiver 30 will be described. An analog-to-digital converter (ADC) 32 converts a frequency down-converted analog signal in the third frequency converter 31 into a digital signal Conversion.

The demodulator 33 demodulates the digital signal converted by the ADC 32 and extracts a signal in the frequency domain from the received signal in the time domain.

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.

10: Transmitting section 20: Magnetic interference signal generating section
21: Baseband magnetic interference signal estimation and generator
30: Receiver

Claims (10)

A transmitter for generating a transmission signal using an input signal of a baseband and transmitting the generated transmission signal through wireless communication,
A magnetic interference signal generator for generating a quasi-magnetic interference signal using the baseband input signal, and
Receiving the transmission signal transmitted from the transmission unit through wireless communication, receiving the quasi-magnetic interference signal from the magnetic interference signal generation unit, and receiving the magnetic interference signal included in the transmission signal using the quasi-static interference signal And extracting a signal from which the magnetic interference signal included in the transmission signal has been removed from the transmission signal and extracting the baseband input signal,
Lt; / RTI >
The magnetic interference signal included in the transmission signal transmitted by the reception unit may include a magnetic interference signal generated by forming the transmission signal into a multi-channel signal when the reception unit receives the transmission signal transmitted from the transmission unit through wireless communication Signal in the OFDM-based wireless communication system. The method according to claim 1,
Wherein the magnetic interference signal generator comprises:
A delay adding unit for modulating the baseband input signal on a subcarrier and adding a delay,
An attenuation unit for multiplying the delay-added signal modulated with the sub-carrier by the delay adding unit by a variable attenuation value,
Wherein the delay adder is performed using Equation (1) below. ≪ EMI ID = 1.0 >
[Formula 1]

Here, M is the number of channels as a natural number of 1 or more,

Is an Mth delay,

Is an Mth delay (

) Is added to the Mth signal,

Is the frequency of the kth subcarrier, and

Respectively represent baseband input signals. 3. The method of claim 2,
Wherein the delay adding unit of the magnetic interference signal generating unit modulates each baseband input signal for a plurality of channels forming the baseband input signal on a subcarrier to add a delay and the attenuator adds the baseband input signal to a subcarrier Characterized in that each baseband input signal for a plurality of channels that are modulated and delay added is multiplied by an attenuation value. The method of claim 3,
Wherein the magnetic interference signal generation unit generates a magnetic interference signal by combining the baseband input signals for the plurality of channels multiplied by the attenuation values in the attenuation unit by adding modulation and delay to the subcarriers in the delay adding unit, part
Wherein the merging unit is performed through Equation (2) below. ≪ EMI ID = 1.0 >
[Formula 2]

here,

The output signal of the merging unit,

A variable attenuation value, and

Respectively represent baseband input signals. 5. The method of claim 4,
And a phase changing unit for changing a phase of the output signal generated by the combining unit. The method of claim 3,
Wherein the delay adding unit adds an equal delay to each of the baseband input signals for the plurality of channels forming the baseband input signal. The method according to claim 6,
Wherein the delay adding unit adjusts the delay value by assigning different weights to the respective baseband input signals for the plurality of channels forming the baseband input signal, Interference cancellation system. The method according to claim 1,
The transmitter may further comprise:
A first OFDM modulator for performing OFDM modulation on the baseband input signal,
The first DAC for converting an OFDM-modulated signal in the first OFDM modulator into an analog signal, and
A first frequency conversion unit for frequency up-converting a signal converted into an analog signal in the first DAC;
Wherein the analog magnetic interference elimination system in the OFDM-based wireless communication system comprises: 6. The method of claim 5,
Wherein the magnetic interference signal generating unit forms the delay adding unit, the attenuating unit, the merging unit, and the phase changing unit as a baseband magnetic interference signal estimating and generating unit,
A second OFDM modulator for OFDM-modulating an output signal output from the phase-shifted output of the baseband magnetic interference signal estimator and generator;
A second DAC for converting a signal modulated by the second OFDM modulator into an analog signal,
A second frequency conversion unit for frequency up-converting a signal converted into an analog signal in the second DAC;
An RF amplifier for amplifying a frequency up-converted signal by the second frequency converter to a signal of a radio communication band;
Wherein the analog magnetic interference elimination system in the OFDM-based wireless communication system comprises: The method according to claim 1,
The receiver may further comprise:
A third frequency converter for frequency downconverting a signal from which the magnetic interference signal included in the transmission signal is removed,
An ADC for converting the frequency down-converted signal from the third frequency converter into a digital signal, and
A demodulator for extracting the baseband input signal from the signal converted into a digital signal by the ADC;
Wherein the analog magnetic interference elimination system in the OFDM-based wireless communication system comprises:

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