KR20230061961A - Apparatus and method for wireless relaying - Google Patents

Abstract

The present invention relates to a wireless relay device and method.
A wireless repeater according to the present invention receives a first signal transmitted from a first wireless communication apparatus, a second signal transmitted from a second wireless communication apparatus, and a feedback interference signal transmitted from a transmitting antenna and introduced through a receiving antenna. receiver; a feedback interference canceling unit for canceling a feedback interference signal sent from the transmitting antenna and received from the signal transmitted from the receiving unit; and a transmitter for transmitting the signal transmitted from the feedback interference canceller to the first wireless communication device and the second wireless communication device through the transmission antenna.

Description

Wireless relay device and method {Apparatus and method for wireless relaying}

The present invention relates to a wireless relay device and method, and more particularly, to a wireless relay device and method used in a mobile communication service employing a Time Division Duplexing (TDD) scheme.

A wireless repeater is a device generally used to eliminate a shadow area within a wireless communication service area, and performs a function of selectively amplifying and retransmitting a signal used in a wireless communication service.

When communication is bi-directional, i.e., downlink (DL) communication in which signals are transmitted from a base station to a terminal, and uplink (UL) communication in which signals are transmitted from a terminal to a base station, such as in a mobile communication service, duplexing (Duplexing) ) method to perform bi-directional communication, representative duplexing methods include a frequency division duplexing (FDD) method and a time division duplexing (TDD) method.

In mobile communication employing a time-division duplex scheme, as shown in FIG. 1, a base station transmits a signal to a terminal during a downlink period (T _DL ) within one period (T) and the terminal receives the signal, and one cycle ( During an uplink period (T _UL ) within T), the terminal transmits a signal to the base station and the base station receives the signal, thereby enabling bi-directional communication. In actual implementation, a boundary where neither a base station nor a terminal transmits a signal at a boundary crossing from a downlink section (T _DL ) to an uplink section (T _UL ) and/or from an uplink section (T _UL ) to a downlink section (T _DL ). It may have a section, but since there is no difference in the present invention, it is not separately distinguished.

As shown in FIG. 2, the conventional wireless repeater 10 for time-division duplexing mobile communication transmits an uplink signal to a base station in an uplink section (T _UL ) and transmits an uplink signal from the base station in a downlink section (T _DL ). A donor antenna 11a for receiving a downlink signal, a service antenna 11b for transmitting a downlink signal to a terminal in a downlink period (T _DL ) and receiving an uplink signal transmitted from a terminal in an uplink period (T _UL ), and a donor antenna The downlink receiver 12a selectively amplifies the frequency components of the signal to be relayed among the signals received from the downlink receiver 12a, the downlink transmitter 13a amplifies the power of the signal transmitted from the downlink receiver, and the signal to be relayed among the signals received from the service antenna. An uplink receiver 12b that selectively amplifies frequency components, an uplink transmitter 13b that amplifies the power of a signal transmitted from the uplink receiver, and a donor antenna switching unit 14a that selectively connects a donor antenna to the downlink receiver or uplink transmitter. , the service antenna switching unit 14b that selectively connects the service antenna to the downlink transmission unit or uplink reception unit, and controls the donor antenna switching unit so that the donor antenna is connected to the downlink reception unit in the downlink period (T _DL ), and the service antenna is connected to the downlink transmission unit. Controls the service antenna switching unit to receive the output, controls the service antenna switching unit so that the service antenna is connected to the uplink receiver in the uplink period (T _UL ), and controls the donor antenna switching unit so that the donor antenna receives the output of the uplink transmitter Synchronization signal A generator 15 and the like are provided.

In the conventional time-division duplex wireless repeater, the donor antenna switching unit and the service antenna switching unit are controlled according to the control of the synchronization signal generator for two-way communication, so that the transmission direction of the signal is switched _. ) and the uplink section (T _UL ) must be accurately determined and a synchronization signal must be generated accordingly.

If the periodicity of the signal propagation direction is clear because the past downlink section (T _DL ) and uplink section (T _UL ) are each fixed, the period is estimated by observing the magnitude of the signal received from both antennas, and synchronization is performed based on this Relatively simple devices for generating signals have been used.

However, the modern mobile communication method in which data service is important takes a period (T), a downlink section (T _DL ), and an uplink section (T _UL ) as variables so that it can easily adapt to changes in data transmission amount, etc. Since the value is determined and transmitted to the terminal, the terminal must determine the timing of receiving and transmitting the signal based on the information received from the base station.

Therefore, the synchronization signal generator of the time-division duplex wireless repeater also acquires information from the communication signal transmitted from the base station, that is, despreading, demultiplexing, channel estimation, and decoding. ).

In addition, when the communication standard is changed, there is the inconvenience of exchanging or modifying these devices, and when the received signal is weak or unstable, the synchronization signal generator enters the initialization process, which takes up until the base station signal and information are reacquired. During that time, wireless repeaters had a problem in that they had to stop functioning.

In addition, the donor antenna switching unit and the service antenna switching unit cause attenuation or deterioration of signals in a signal transmission path.

Korean Registered Patent Publication No. 10-0697209

The present invention was invented to solve the above problems, and an object of the present invention is to relay a wireless signal without a synchronization signal generator in a time division duplex mobile communication service, that is, reverse distribution, demultiplexing, channel An object of the present invention is to provide a wireless relay device and method capable of relaying a wireless signal without performing an information acquisition process such as estimation and decoding.

Another object of the present invention is to provide a wireless relay device and method capable of relaying a wireless signal without being affected by variables such as period, downlink section, uplink section, etc. in a time division duplex mobile communication service.

Another object of the present invention is to provide a wireless relay apparatus and method capable of efficiently relaying a time-division duplexing radio signal using one reception-only antenna and one transmission-only antenna without a donor/service antenna switching unit.

Another object of the present invention is to remove the feedback interference signal sent from the transmitting antenna and flowed into the receiving antenna to provide a wireless relay device and method for relaying the refined base station signal and terminal signal in a stable state without oscillation caused by feedback. is to do

For the above purpose, a wireless repeater according to one embodiment of the present invention includes a first signal transmitted from a first wireless communication apparatus, a second signal transmitted from a second wireless communication apparatus, and feedback interference transmitted from a transmission antenna and introduced. a receiving unit for receiving a signal through a receiving antenna; a feedback interference canceling unit for canceling a feedback interference signal sent from the transmitting antenna and received from the signal transmitted from the receiving unit; and a transmitter for transmitting the signal transmitted from the feedback interference canceller to the first wireless communication device and the second wireless communication device through the transmission antenna.

Preferably, the feedback interference cancellation unit includes: a channel estimator generating a feedback interference channel estimate by estimating a channel of a path transmitted from the transmission antenna and flowing into the reception antenna; a linear combiner for generating a feedback interference estimation value based on the feedback interference channel estimation value estimated by the channel estimator and the output of the feedback interference cancellation unit; and a subtractor for subtracting the estimated feedback interference from the signal transmitted from the receiver.

On the other hand, in the wireless relay method according to one embodiment of the present invention, the receiver receives a first signal transmitted from a first wireless communication device, a second signal transmitted from a second wireless communication device, and feedback interference transmitted from the transmission antenna and introduced receiving a signal through a receiving antenna; canceling, by a feedback interference cancellation unit, a feedback interference signal transmitted from the transmission antenna and received from the signal transmitted from the reception unit; and transmitting, by a transmitter, the signal transmitted from the feedback interference cancellation unit to the first wireless communication device and the second wireless communication device through the transmission antenna.

Preferably, the removing step includes estimating a channel of a path transmitted from the transmitting antenna and flowing into the receiving antenna to generate a feedback interference channel estimation value; generating a feedback interference estimation value based on the generated feedback interference channel estimation value and the output of the feedback interference cancellation unit; and subtracting the estimated feedback interference from the signal transmitted by the receiver.

According to the present invention, since a receiving unit, a feedback interference canceling unit, and a transmitting unit are implemented in a common downlink/uplink path using one reception-only antenna and one transmission-only antenna, synchronization with the donor/service antenna switching unit according to the prior art is achieved. Since a signal generating unit is not required, it has an effect of providing a simple and efficient time-division duplex wireless repeater and method.

In addition, according to the present invention, since the feedback interference cancellation unit removes the feedback interference signal transmitted from the transmission antenna and introduced into the reception antenna, it efficiently relays the base station signal and the terminal signal refined in a stable state without oscillation caused by feedback. have an effect that can

In addition, according to the present invention, information acquisition processes such as de-distributing, demultiplexing, channel estimation, and decoding are not performed in a time-division duplex mobile communication service, and are not affected by variables such as period, downlink section, and uplink section. Since the wireless signal can be relayed without having to do so, complexity can be greatly reduced compared to the prior art, and thus economic efficiency and performance can be improved.

1 is a timing diagram illustrating a time division duplexing method.
2 is a block diagram of a time division duplex wireless repeater according to the prior art.
3 is a configuration diagram of a wireless repeater according to a first embodiment of the present invention.
4 is a diagram showing a mathematical model of a wireless repeater according to a first embodiment of the present invention.
5 is a configuration diagram of a wireless repeater according to a second embodiment of the present invention.
6 is a detailed configuration diagram of the digital signal processor of FIG. 5;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments. For reference, in the following description, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

3 is a configuration diagram of a wireless repeater according to a first embodiment of the present invention.

Referring to FIG. 3, the wireless repeater 100 according to the first embodiment of the present invention includes a downlink signal (first signal) transmitted from a base station (first wireless communication apparatus) and a terminal (second wireless communication apparatus) A receiving antenna ANT1 for receiving an upward signal (second signal) transmitted from the receiving antenna ANT1, a receiving unit 110 for selectively amplifying a frequency component of a signal to be relayed among signals received through the receiving antenna ANT1, and a receiving unit 110 A feedback interference cancellation unit 150 that removes the feedback interference introduced from the transmission antenna ANT2 in the signal transmitted from ), a transmission unit 190 that amplifies the power of the signal transmitted from the feedback interference cancellation unit 150, and a transmission unit ( 190) includes a transmission antenna (ANT2) for transmitting the amplified signal to the terminal and the base station.

As shown in FIG. 3, the wireless repeater 100 according to the first embodiment of the present invention includes two antennas directed in both directions between the base station and the terminal, that is, a reception-only antenna ANT1 and a transmission-only antenna ANT2. The receiving antenna ANT1 always receives the signal transmitted from the base station (downlink signal) and the signal transmitted from the terminal (uplink signal), and the transmitting antenna ANT2 does not operate by dividing the time. ANT1) amplifies the received signal and always transmits it to the terminal and base station.

In this process, a part of the signal transmitted from the transmitting antenna ANT2 is introduced back to the receiving antenna ANT1, and as a result, the receiving antenna ANT1 transmits the downlink signal transmitted from the base station, the uplink signal transmitted from the terminal, and the transmit antenna. All of the feedback signals transmitted from ANT2 and introduced into the receiving antenna ANT1 are received.

Therefore, as shown in FIG. 3, the wireless repeater 100 according to the first embodiment of the present invention receives the downlink signal transmitted from the base station and the uplink signal transmitted from the terminal through the transmission antenna ANT2. After the feedback signal flowing into the antenna ANT1 is amplified by the receiving unit 110, the feedback interference cancellation unit 150 removes the feedback signal transmitted from the transmitting antenna ANT2 and flowing into the receiving antenna ANT1, so that the base station Extracts only the downlink signal transmitted from the terminal or the uplink signal transmitted from the terminal, and the transmitter 190 amplifies the power of the signal (downlink signal of the base station or uplink signal of the terminal) transmitted from the feedback interference cancellation unit 150 to obtain a transmit antenna It is transmitted to the terminal and the base station through (ANT2).

As described above, in the time division duplexing (TDD) method, an uplink signal is not transmitted during a downlink period (T _DL ) in which a downlink signal is transmitted, and a downlink signal is transmitted during an uplink period (T _UL ) in which an uplink signal is transmitted. Therefore, the receiving antenna ANT1 receives only one of the downlink signal of the base station and the uplink signal of the terminal according to the downlink/uplink section.

Therefore, in the first embodiment of the present invention, the feedback interference cancellation unit 150 is designed to prevent signal deterioration due to interference of a downlink signal to an uplink signal and/or interference of an uplink signal to a downlink signal. This is to stabilize the operation by reducing the closed loop loop gain of the “receiving antenna (ANT1) - receiving unit 110 - transmitting unit 190 - transmitting antenna (ANT2)”. That is, the feedback interference cancellation unit 150 is to protect the quality of the base station signal and the terminal signal by removing the feedback interference of the signal transmitted from the transmission antenna ANT2 and flowing back to the reception antenna ANT1.

FIG. 4 shows the device of FIG. 3 as a mathematical model to explain the principle of the wireless relay device according to the first embodiment of the present invention.

_F(t)는 궤환 간섭 채널의 임펄스 응답에 대한 추정치이고,

_F(t)는 궤환 간섭 추정치이다. 그리고, δ(t)는 단위 임펄스 함수(Unit Impulse Function)이고, τ_RX는 수신부(110)의 시간 지연치이다.Here, G _RX is the amplification degree of the receiver 110, G _TX is the amplification degree of the transmitter 190, h ₂₁ (t) is the channel impulse response between the transmit antenna (ANT2) and the receive antenna (ANT1) ), and i ₂₁ (t) is a feedback interference signal introduced from the transmission antenna ANT2 to the reception antenna ANT1. Further, s _DL (t) is a transmission signal of the base station, s _UL (t) is a transmission signal of the terminal, and y (t) is a transmission signal of the transmit antenna (ANT2). Then, r(t) is an input signal of the feedback interference cancellation unit 150, x(t) is an output signal of the feedback interference cancellation unit 150,

_F (t) is an estimate of the impulse response of the feedback interference channel,

_F (t) is the feedback interference estimate. And, δ(t) is a unit impulse function, and τ _RX is a time delay value of the receiver 110.

For reference, since this description is limited to the selected signal band used for service, the band-pass filtering function is omitted. And, for convenience of description, it is assumed that the period T, the downlink period T _DL , and the uplink period T _UL each have a constant value.

First, the signal y(t) transmitted from the transmitter 190 can be expressed as Equation 1 below.

[Formula 1]

y(t) = _GTX x(t)

Also, the output signal x(t) and the input signal r(t) of the feedback interference cancellation unit 150 can be expressed as Equations 2 and 3 below. Here, ν(t) is thermal noise for the input of the receiver 110, and operator * is a convolution operator.

[Formula 2]

_F(t)x(t) = r(t) -

_F (t)

[Formula 3]

r(t) = G _RX [s _DL (t) + s _UL (t) + ν(t) + i ₂₁ (t)] * δ(t-τ _RX )

The path where the output x(t) of the feedback interference cancellation unit 150 is fed back to the input r(t) of the feedback interference cancellation unit 150 is the path through which the signal transmitted from the transmission antenna ANT2 flows into the reception antenna ANT1. Since it is formed by the feedback path, the impulse response h _F (t) of the feedback interference channel can be expressed as Equation 4 below.

[Formula 4]

h _F (t) = G _TX G _RX * δ(t-τ _RX ) * h ₂₁ (t)

_F(t)는 하기 수식 5와 같이 표현될 수 있다.Here, if the estimation error for the feedback interference channel is ε(t), the estimated impulse response of the feedback interference channel estimated by the feedback interference cancellation unit 150

_F (t) can be expressed as in Equation 5 below.

[Formula 5]

_F(t) = h_F(t) + ε(t)

_F (t) = h _F (t) + ε(t)

_F(t)는 각각 하기 수식 6 및 7과 같이 표현될 수 있다.And, the feedback interference i _F (t) (i.e., i ₂₁ (t)) and the estimated feedback interference

_F (t) can be expressed as Equations 6 and 7, respectively.

[Formula 6]

i _F (t) = x(t) * h _F (t)

[Formula 7]

_F(t) = x(t) *

_F(t)

_F (t) = x(t) *

_F (t)

Therefore, the output signal x(t) of the feedback interference cancellation unit 150 from Equations 2 to 7 above can be arranged as Equation 8 below.

[Formula 8]

x(t) = G _RX [s _DL (t-τ _RX ) + s _UL (t-τ _RX ) + ν(t-τ _RX )] - x(t) * ε(t)

Therefore, the signal y(t) transmitted from the transmitter 190 can be arranged as shown in Equation 9 below from Equations 1 and 8 above.

[Formula 9]

y(t) = G _TX G _RX [s _DL (t-τ _RX ) + s _UL (t-τ _RX ) + ν(t-τ _RX )] - G _TX x(t) * ε(t)

However, in the time division duplex (TDD) scheme, since the base station signal s _DL (t) and the terminal signal s _UL (t) do not exist at the same time, when the transmission signal of the transmitter 190 is in the downlink section (T _DL ), Equation 10 and Likewise, in the case of the uplink section (T _UL ), it can be arranged as in Equation 11 below.

[Equation 10]

y(t) = G _TX G _RX [s _DL (t-τ _RX ) + ν(t-τ _RX )] - G _TX x(t) * ε(t) [Descent section]

[Equation 11]

y(t) = G _TX G _RX [s _UL (t-τ _RX ) + ν(t-τ _RX )] - G _TX x(t) * ε(t) [Upward]

Therefore, even if there is no antenna switching unit and synchronization signal generator, the relaying function can be performed in a stable state without feedback interference by using only one feedback interference cancellation unit 150 regardless of uplink/downlink.

Equations 1 to 11 are expressed as continuous time signals and systems, but since the wireless repeater is a band-limited system in which the service band is determined, part of the signal processing including the feedback interference cancellation unit 150 is performed by a digital signal processor (DSP). ; Digital Signal Processor).

_pq(t)는 0 < t < T_pq에 대해서만 추정한다. 유효채널구간은 다양한 기준으로 결정할 수 있으며, 예를 들면 t > T_pq 동안 |ε_DL(t)|² >> |h_pq(t)|² 인 T_pq일 수 있다.In addition, the feedback channel h _pq (t) (here p=2, q=1) is a causal system because it is formed by scatterers and reflectors that exist on the propagation path of radio waves, and power increases over time. It is a dying system. That is, at t<0, and if t→Δ, h _pq (t) = 0. Therefore, in implementing the feedback interference cancellation unit 150, if the effective channel interval is T _pq , the channel estimate

_pq (t) is estimated only for 0 < t < T _pq . The effective channel interval can be determined by various criteria, for example |ε _DL (t)| while t > T _pq ² >> |h _pq (t)| It may be T _pq which is ² .

5 is a configuration diagram of a wireless repeater according to a second embodiment of the present invention. For reference, the second embodiment of the present invention more specifically implements the first embodiment of the present invention described above.

Referring to FIG. 5 , the wireless repeater 200 according to the second embodiment of the present invention includes a downlink signal (first signal) transmitted from a base station (first wireless communication apparatus) and a terminal (second wireless communication apparatus) A receiving antenna (ANT1) for receiving the uplink signal (second signal) transmitted from the receiving antenna (ANT1), a variable gain amplifier 210 for appropriately amplifying the signal received through the receiving antenna (ANT1) for signal processing, and a variable gain amplifier (210) ), the first frequency converter 220 converts (transitions) the amplified signal into a frequency band that can be processed by a band pass filter and an AD converter (Analog to Digital Conversion), and is transmitted in the first frequency converter 220 The first band filter 230 selectively passes the signal of the service frequency band to be relayed among the transmitted signals, and converts the analog signal output from the first band filter 230 into a digital signal through sampling and quantization. AD converter 240, digital signal processor 250, which removes the feedback interference introduced from the transmission antenna (ANT2) in the digital signal output from the AD converter 240, digital signal output from the digital signal processor 250 A DA converter 260 that converts into an analog signal, a second band filter 270 that removes signals in an unnecessary frequency band among analog signals transferred from the DA converter 260, and a signal that has passed through the second band filter 270 The second frequency converter 280 converts back to the original received frequency band, the power amplifier 290 amplifies the power of the signal frequency-converted by the second frequency converter 280, and the signal amplified by the power amplifier 290 Including a transmit antenna (ANT2) for transmitting to the terminal and the base station, a radio relay function is performed for the down path from the base station to the terminal and the up path from the terminal to the base station.

For reference, some of the analog signal processing processes may be processed separately by an analog signal processor and a digital signal processor, or may be moved to either one. For example, in the case of the band pass filter function, in the embodiment of FIG. 5, it is implemented as a band filter using an analog filter, but as another implementation form, the analog filter removes only the aliasing component and uses the service band in the digital signal processor. It is also possible to perform a band filtering process that selects . In addition, time delay occurs in each of the above-described processing processes, and in general, the most time delay occurs in the band pass filter.

6 is a detailed configuration diagram of the digital signal processor of FIG. 5;

_F)를 생성하는 채널 추정기(250a), 채널 추정기(250a)에서 추정된 궤환 간섭 채널 추정치(

_F)에 따라 디지털 신호 처리기(250)의 출력(x)을 조합하여 궤환 간섭 추정치(

_F)를 생성하는 선형 조합기(250b), AD 변환기(240)로부터의 입력 신호(r)에서 선형 조합기(250b)에서 추정된 궤환 간섭 추정치(

_F)를 감산하는 감산기(250c) 등을 포함한다.As shown in FIG. 6, the digital signal processor 250 according to an embodiment of the present invention estimates the feedback interference channel ( h _F ) to obtain a feedback interference channel estimation value (

The channel estimator 250a that generates _F ), the estimated feedback interference channel estimate from the channel estimator 250a (

According to _F ), the feedback interference estimation value (

The linear combiner 250b that generates _F ), the estimated feedback interference estimate in the linear combiner 250b from the input signal r from the AD converter 240 (

and a subtractor 250c that subtracts _F ).

_F(n)를 생성하고, 선형 조합기(250b)는 채널 추정기(250a)에서 생성된 궤환 간섭 채널 추정치

_F(n)를 가중상수로 이용하여 디지털 신호 처리기(250)의 출력 x(n) 및 그 과거 값(x(n-1), x(n-2), ... )을 조합하여 궤환 간섭 추정치

_F(n)을 생성하며, 감산기(250c)는 AD 변환기(240)로부터의 입력 r(n)에서 궤환 간섭 추정치

_F(n)을 감산하여 x(n)을 출력한다.In detail, the AD converter 240 transmits a discrete time signal r(n) sampled at every T _S time interval to the digital signal processor 250. Then, the channel estimator 250a estimates the feedback interference channel based on the output r(n) of the AD converter 240 and the output x(n) of the digital signal processor 250

_F (n) is generated, and the linear combiner 250b is the feedback interference channel estimate generated by the channel estimator 250a

Feedback interference by combining the output x(n) of the digital signal processor 250 and its past values (x(n-1), x(n-2), ...) using _F (n) as a weighting constant estimate

Subtractor 250c produces _F (n), the feedback interference estimate at input r(n) from AD converter 240

Subtract _F (n) to output x(n).

If the transpose is expressed as a superscript T and the conjugate transpose as a superscript H, the above process is formulated as follows.

_F(n)는 선형 조합기(250b)에서 궤환 간섭 채널 추정치 벡터

_F(n)와 디지털 신호 처리기(250)의 출력 벡터 x(n)를 연산하여, 예컨대 내적(inner product)을 산출하여 얻을 수 있다.First, the output x(n) of the subtractor 250c can be expressed as Equation 12 below, and the feedback interference estimate

_F (n) is a feedback interference channel estimation vector in the linear combiner 250b

It can be obtained by calculating _F (n) and the output vector x (n) of the digital signal processor 250 to calculate, for example, an inner product.

[Equation 12]

_F(n)x(n) = r(n) -

_F (n)

_F ^H(n)x(n)= r(n) -

_F ^H (n) x (n)

_F(n)은 하기 수식 13과 같이 크기가 N×1인 행렬로 표현될 수 있으며, 디지털 신호 처리기(250)의 출력 벡터 x(n)도 마찬가지로 하기 수식 14와 같이 크기가 N×1인 행렬로 표현될 수 있다. 여기서, 행렬의 길이 N은

_F(t)의 유효채널구간을 기준으로 정해질 수 있다. 예컨대, h₂₁(t)의 유효 채널 길이에 의해 결정될 수 있다.Here, the feedback interference channel estimate vector

_F (n) can be expressed as a matrix of size N × 1 as shown in Equation 13 below, and the output vector x (n) of the digital signal processor 250 is also a matrix of size N × 1 as shown in Equation 14 below. can be expressed as Here, the length N of the matrix is

It can be determined based on the effective channel interval of _F (t). For example, it may be determined by the effective channel length of h ₂₁ (t).

[Equation 13]

_F(n) = [

_F.N-1(n)

_F.N-2(n) ...

_F.0(n)]^T

_F (n) = [

_FN-1 (n)

_FN-2 (n) ...

_F.0 (n)] ^T

[Equation 14]

x (n) = [x(n-N+1) x(n-N+2) ... x(n)] ^T

In the channel estimation function, since the feedback channel is a time varying channel, the channel estimator according to a preferred embodiment of the present invention uses the LMS (Least Mean Square) algorithm, RLS (Recursive Least Square) algorithm, and GN (Gauss-Newton) ) is implemented as an adaptive filter using an adaptive algorithm such as the algorithm.

[Equation 15]

(n+1) =

(n) + Ψ{h(n),α(n),β(n),γ(n)}

(n+1) =

(n) + Ψ { h (n), α (n), β (n), γ (n)}

(n)을 개선하기 위한 조정치로서 LSM, RLS, GN 등 적용되는 알고리즘에 의해 결정되는 함수이다. 여기서, α(n)은 입력신호, 예컨대 r(n)과 그 과거 값(r(n-1), r(n-2), ... )일 수 있고, β(n)은 선형조합에 기여하는 표본, 예컨대 x(n)과 그 과거 값(x(n-1), x(n-2), ... )일 수 있으며, γ(n)은 오차성분을 포함한 감산결과, 예컨대 x(n)과 그 과거 값일 수 있다.where Ψ { h (n), α (n), β (n), γ (n)} is the estimate

As an adjustment value to improve (n), it is a function determined by an applied algorithm such as LSM, RLS, or GN. Here, α (n) can be an input signal, such as r (n) and its past values (r (n-1), r (n-2), ...), and β (n) is It can be a contributing sample, eg x(n) and its past values (x(n-1), x(n-2), ...), and γ (n) is a subtraction result including an error component, eg x (n) and its past value.

(n)를 적용하여 간섭 성분을 제거한 후 그 결과로서 발생된 오차를 기반으로 현재의 추정치를 조정하여

(n+1)을 산출한다.That is, the channel estimator according to the preferred embodiment of the present invention is the current channel estimate

After removing the interference component by applying (n), the current estimate is adjusted based on the resulting error.

yields (n+1).

Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art to which the present invention pertains can implement it in various other specific forms without changing the technical spirit or essential features of the present invention. The embodiments are to be understood as illustrative in all respects and not restrictive.

In addition, the scope of the present invention is specified by the claims to be described later rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. should be interpreted as

Claims (6)

As a wireless repeater,
a receiver configured to receive a first signal transmitted from a first wireless communication device, a second signal transmitted from a second wireless communication device, and a feedback interference signal transmitted from a transmitting antenna and received through a receiving antenna;
a feedback interference canceling unit for canceling a feedback interference signal sent from the transmitting antenna and received from the signal transmitted from the receiving unit; and
and a transmitter for transmitting the signal transmitted from the feedback interference cancellation unit to the first wireless communication device and the second wireless communication device through the transmission antenna. According to claim 1,
The feedback interference cancellation unit estimates the feedback interference signal transmitted from the transmission antenna and received based on the amplification degree of the transmission unit, the channel between the transmission antenna and the reception antenna, and the amplification degree of the reception unit. . According to claim 1 or 2,
The feedback interference cancellation unit,
a channel estimator for generating a feedback interference channel estimate by estimating a channel of a path transmitted from the transmission antenna and flowing into the reception antenna;
a linear combiner for generating a feedback interference estimation value based on the feedback interference channel estimation value estimated by the channel estimator and the output of the feedback interference cancellation unit; and
and a subtractor for subtracting the estimated feedback interference from the signal transmitted from the receiver. According to claim 3,
The channel estimator is implemented as an adaptive filter that takes the signal transmitted from the receiver and the signal output from the feedback interference canceller as inputs. As a wireless relay method,
receiving, by a receiving unit, a first signal transmitted from a first wireless communication device, a second signal transmitted from a second wireless communication device, and a feedback interference signal transmitted from the transmission antenna and received through a reception antenna;
canceling, by a feedback interference cancellation unit, a feedback interference signal transmitted from the transmission antenna and received from the signal transmitted from the reception unit; and
and transmitting, by a transmitter, the signal transmitted from the feedback interference cancellation unit to the first wireless communication device and the second wireless communication device through the transmission antenna. According to claim 5,
The step of removing is
generating a feedback interference channel estimation value by estimating a channel of a path transmitted from the transmission antenna to the reception antenna;
generating a feedback interference estimation value based on the generated feedback interference channel estimation value and the output of the feedback interference cancellation unit; and
and subtracting the estimated feedback interference from the signal transmitted by the receiver.

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