KR102049925B1 - Data Transmitting Apparatus and Data Receiving Apparatus for Improving Spectral Efficiency - Google Patents

Abstract

The present invention relates to a data transmission apparatus and a reception apparatus, and in particular, to an apparatus for transmitting data using an induced synchronization sequence that eliminates intersymbol interference superimposed on a time domain in which an adaptively adjusted preamble is transmitted in an FBMC system. To start. The data transmission apparatus of the present invention inversely Fourier transforms a data symbol to be transmitted and a synchronization sequence for removing intersymbol interference of the data symbol based on at least one filter having a predetermined frequency response to perform at least one modulation symbol. A modulator to generate; And a communication unit for superimposing and transmitting the generated modulation symbols and a preamble for synchronization of the data symbols on a time axis. It includes.

Description

Data Transmitting Apparatus and Data Receiving Apparatus for Improving Spectral Efficiency}

The present invention relates to a data transmission apparatus and a reception apparatus. More particularly, the present invention relates to a data transmission device and a reception device for data transmission and reception in an FBMC system.

Recently, a mobile communication system has a physical layer transmission structure based on an OFDM system, but as the Internet of Things (IOT) and Machine-to-Machine (M2M) markets expand, a system having a higher frequency efficiency than an OFDM system is needed. Is getting. Accordingly, the Filter Bank Multi Carrier (FBMC) system has been actively studied as a new physical layer transmission technique for the next generation mobile communication system.

FBMC requires higher complexity than OFDM, but due to the Confinement feature of the prototype filter, unlike OFDM, it has the advantage of preventing the loss of frequency efficiency due to the insertion of Cyclic Prefix (CP) and Guard Band. FBMC is a multi-carrier modulation technique, and it is very important to match synchronization at a transmitter and a receiver.

In the case of the FBMC system, there is a problem that the envelope of the transmission signal by the prototype filter changes during the filtering process, and the interference between the FBMC symbols occurs in the overlapping process on the time axis, which is performed based on correlation. Adversely affect the preamble synchronization process.

Therefore, there is a need for a technology development that can improve frequency efficiency while eliminating interference components caused by FBMC symbols overlapping the preamble.

Korean Unexamined Patent No. 10-2016-0120654 (published)

The present invention has been made in view of solving the above problems, and discloses a data transmission apparatus and a reception apparatus. In particular, a transmitter and a receiver for transmitting data by inducing a synchronization sequence for removing intersymbol interference superimposed on a time domain in which an adaptively adjusted preamble is to be transmitted are disclosed.

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the apparatus for transmitting data of the present invention includes at least one data symbol to be transmitted and a synchronization sequence for removing interference between symbols of the data symbol having a preset frequency response. A modulator for generating at least one modulation symbol by inverse Fourier transform based on a filter; And a communication unit for superimposing and transmitting the generated modulation symbols and a preamble for synchronization of the data symbols on a time axis. It includes.

The modulator may include: a first modulator configured to generate a first modulated symbol by inverse Fourier transforming the data symbol based on the filter; Further comprising, the modulation symbols may include the first modulation symbol.

In the present invention, the modulator induces a synchronization sequence for removing inter-symbol interference of the first modulation symbol in the time domain in which the preamble is transmitted, and inversely Fourier transforms the derived synchronization sequence based on the filter to generate a second sequence. A second modulator for generating a modulation symbol; Further comprising, the modulation symbols may include the second modulation symbol.

In the present invention, the data transmission apparatus includes a resource setting unit that presets a transmission resource for transmitting a data symbol, the synchronization sequence and the preamble; The transmission resource may further include at least one of a frequency characteristic of a subcarrier for transmitting the data symbol and the synchronization sequence and a time domain in which the preamble is transmitted.

In the present invention, the data symbols are offset quadrature amplitude modulation (OQAM) data symbols or quadrature amplitude modulation (OQAM) modulated by applying an offset to one of a real part or an imaginary part arranged at predetermined intervals. Amplitude Modulation (QAM) data symbol, wherein the modulator uses the filter bank multicarrier (FBMC) scheme based on a filter having the preset frequency response and subcarriers of different frequency bands. Can create them.

In the present invention, the first modulator comprises: a mapping unit for mapping the data symbols to subcarriers having different frequency bands; And a first frequency that convolves a data symbol mapped to the subcarrier on a frequency axis with a prototype filter, the filter having the preset frequency response, and inverse Fourier transforms the data symbol convolved with the prototype filter. Inverse transform unit; The method may further include: generating the first modulation symbol by using the data symbol convolved with the prototype filter and inversely Fourier transformed.

In the present invention, the second modulator includes an interference inducing unit for inducing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted; And a synchronization sequence derivation unit for deriving a synchronization sequence for removing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain. The apparatus may further include and generate the second modulation symbol by using the derived synchronization sequence.

In the present invention, the second modulator comprises: a selector for selecting a subcarrier region for transmitting the derived synchronization sequence; And convolving the synchronization sequence mapped to the subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter which is a filter having a predetermined frequency response, and inverting the synchronization sequence convolved with the prototype filter. A second frequency inverse transform unit for Fourier transform; Further comprising, deriving the synchronization sequence using the selected subcarrier region, the time domain in which the preamble is transmitted, and the inter-symbol interference (ISI) overlapping in the time domain, and convoluted with the prototype filter to inverse Fourier The second modulation symbol may be generated using the converted synchronization sequence.

In the present invention, the communication unit transmits the first modulation symbol, the second modulation symbol and the preamble by overlapping in the time domain in which the preamble is transmitted, and the subcarriers for transmitting the synchronization sequence have the same interval in the frequency domain. It may be provided as a set of the subcarriers.

In addition, in order to achieve the above object, the data receiving apparatus of the present invention provides the modulation symbol based on cross-correlation of modulation symbols in which at least one data symbol received from a transmitter is modulated and a preamble for synchronizing the data symbol. Synchronizing unit for obtaining the synchronization of the; A preamble remover configured to remove the preamble from the modulation symbols based on an impulse response of a channel through which the modulation symbols are transmitted and a convolution operation of the preamble from the obtained synchronization symbols; And a data symbol detector configured to perform Fourier transform on the modulation symbols from which the preamble is removed based on at least one filter having a preset frequency response to detect the data symbols. It includes.

In the present invention, the data receiving apparatus includes: a channel estimating unit estimating a state of a channel by calculating an impulse response according to a frequency characteristic of a channel through which the modulation symbols are transmitted; The preamble removing unit may remove the preamble from the modulation symbols by using the calculated impulse response of the channel.

In the present invention, the data symbol detector Fourier transforms the modulation symbols from which the preamble is removed in consideration of the frequency response of the filter, and different weights of a prototype filter that is a filter having a preset frequency response. A demodulator for demodulating the Fourier transformed modulation symbols using < RTI ID = 0.0 > The apparatus may further include: detecting the data symbol using the demodulated modulation symbols.

The data symbol detector may include: a demapping unit configured to demap the demodulated modulation symbols mapped to subcarriers having different frequency bands to different frequency bands of the subcarriers; Further, the data symbols may be detected using the demapped and demodulated modulation symbols.

In addition, to achieve the above object, the data transmission method of the present invention comprises the steps of generating a first modulation symbol by inverse Fourier transform the data symbol to be transmitted based on at least one filter having a predetermined frequency response; Generating a second modulation symbol by inverse Fourier transforming a synchronization sequence for removing intersymbol interference of the first modulation symbol in a time domain in which a preamble for synchronization of the data symbol is transmitted based on the filter; And transmitting the generated first modulation symbol, the generated second modulation symbol, and the preamble by overlapping on a time axis. It includes.

In the present invention, the data transmission method includes the steps of: preset transmission resources for transmitting the data symbol, the synchronization sequence, and the preamble; Wherein the transmission resource includes at least one of a frequency characteristic of a subcarrier for transmitting the data symbol and the synchronization sequence and a time domain in which the preamble is transmitted, wherein the first modulation symbol and the second modulation symbol May be generated using the transmission resource.

In the present invention, the data symbols are offset quadrature amplitude modulation (OQAM) data symbols or quadrature amplitude modulation (OQAM) modulated by applying an offset to one of a real part or an imaginary part arranged at predetermined intervals. An inverse Fourier transform based on at least one filter including an Amplitude Modulation (OQAM) data symbol and based on at least one filter having the predetermined frequency response is based on a filter bank based on a filter having the predetermined frequency response and subcarriers of different frequency bands. It may include a multi-carrier (Filter Bank Multicarrier, FBMC) scheme.

The generating of the first modulation symbol may include mapping the data symbol to subcarriers having different frequency bands; And convolving a data symbol mapped to the subcarrier on a frequency axis with a prototype filter, the filter having the preset frequency response, and inversely Fourier transforming the data symbol convolved with the prototype filter. The method may further include: generating the first modulation symbol by using the data symbol convolved with the prototype filter and inversely Fourier transformed.

In the present invention, the generating of the second modulation symbol comprises: inducing inter-symbol interference (ISI) of the first modulation symbol overlapping in a time domain in which the preamble is transmitted; And deriving a synchronization sequence for canceling inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain; The apparatus may further include and generate the second modulation symbol by using the derived synchronization sequence.

Generating the second modulation symbol in the present invention includes selecting a subcarrier region for transmitting the derived synchronization sequence; And convolving the synchronization sequence mapped to the subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter which is a filter having a predetermined frequency response, and inverting the synchronization sequence convolved with the prototype filter. Fourier transform; Further comprising, deriving the synchronization sequence using the selected subcarrier region, the time domain in which the preamble is transmitted, and the inter-symbol interference (ISI) overlapping in the time domain, and convoluted with the prototype filter to inverse Fourier The second modulation symbol may be generated using the converted synchronization sequence.

In the present invention, the time domain for transmitting the preamble is selected as an area having a large magnitude of the filter coefficient in consideration of an impulse response of the prototype filter, and the subcarriers for transmitting the synchronization sequence have the same interval in the frequency domain. It may be provided as a set of the subcarriers.

In addition, the data receiving method of the present invention to achieve the above object is based on the cross-correlation of the modulation symbols in which at least one data symbol received from the transmitting side is modulated and the preamble for synchronization of the data symbols of the modulation symbols Obtaining motivation; Estimating a state of a channel by calculating an impulse response according to a frequency characteristic of a channel through which the modulation symbols are transmitted; Removing the preamble from the modulation symbols based on the impulse response of the channel and the convolution operation of the preamble in the synchronized modulation symbols; And detecting the data symbols by Fourier transforming the modulation symbols from which the preamble is removed based on at least one filter having a preset frequency response. It includes.

In the present invention, the detecting of the data symbols includes Fourier transforming modulation symbols from which the preamble is removed in consideration of the frequency response of the filter and different weights of a prototype filter which is a filter having a preset frequency response. Demodulating Fourier transformed modulation symbols using Filter Weighted; And demapping the demodulated modulation symbols mapped to subcarriers having different frequency bands to different frequency bands of the subcarriers. Further, the data symbols may be detected using the demapped and demodulated modulation symbols.

The present invention also discloses a computer program stored in a computer-readable recording medium for executing the above-described data transmission method and data reception method in a computer.

According to the present invention, a desired data symbol can be received by removing interference components of the data symbol.

In particular, according to the present invention, there is an advantage in that data can be transmitted using a synchronization technique with improved spectral efficiency compared to the conventional technique.

1 is a block diagram of a data transmission apparatus according to an embodiment of the present invention.
FIG. 2 is an exemplary diagram illustrating a method of determining a time domain for transmitting a preamble among transmission resources set by a resource setting unit in the embodiment of FIG. 1.
3 is an exemplary diagram illustrating a frequency interval of a subcarrier for transmitting a synchronization sequence by a resource setting unit in the embodiment of FIG. 1.
4 is an enlarged block diagram of a first modulator in the embodiment of FIG. 1.
FIG. 5 is an enlarged block diagram of a second modulator in the embodiment of FIG. 1.
FIG. 6 is a reference diagram illustrating a process for inducing a sync sequence by the sync sequence inducing unit in the embodiment of FIG. 5.
7 is a reference diagram illustrating a result of comparing correlation between a transmission signal and a preamble according to an embodiment of the present invention.
8 is an exemplary view illustrating a process of a data transmission method according to an embodiment of the present invention.
9 is a block diagram of a data receiving apparatus according to an embodiment of the present invention.
FIG. 10 is an enlarged block diagram of a data symbol detector in the embodiment of FIG. 9.
11 is a flowchart illustrating a data transmission method according to an embodiment of the present invention.
FIG. 12 is an enlarged flowchart of generating a first modulation symbol in the embodiment of FIG. 11.
FIG. 13 is an enlarged flowchart of generating a second modulation symbol in the embodiment of FIG. 11; FIG.
14 is a flowchart illustrating a data receiving method according to an embodiment of the present invention.
15 is an enlarged flowchart of detecting data symbols in the embodiment of FIG. 14.
16 is a reference diagram comparing the performance of a data transmission apparatus according to the type and length of a preamble.
17 is a reference diagram comparing the performance of a data transmission apparatus according to the type and length of a preamble.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the description with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals and redundant description thereof will be omitted. In describing the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the gist of the present invention, the detailed description may be omitted. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of terms. Singular expressions include plural expressions unless the context clearly indicates otherwise. Each step described below may be provided by one or several software modules or may be implemented by hardware that is responsible for each function, or may be a combination of software and hardware. Specific meanings and examples of each term will be described below in the order of the drawings. Hereinafter, the configuration of the data transmission apparatus 10 and the data receiving apparatus 20 according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a data transmission apparatus 10 according to an embodiment of the present invention.

The data transmission apparatus 10 of the present invention includes a resource setting unit 100, a first modulation unit 200, a second modulation unit 300, and a communication unit 400. For example, in the wireless communication system based on the FBMC system (FBMC), the data transmission apparatus 10 removes an interference component caused by FBMC modulation symbols overlapping the preamble and generates a synchronization sequence for generating a desired preamble. The inter-symbol interference (ISI) can be eliminated through the deriving configuration. In addition, unlike the prior art, in which the data transmission apparatus 10 of the present invention had to utilize an entire FBMC symbol for a synchronization process, the data transmission apparatus 10 sets a sequence which can be adaptively adjusted as a preamble and uses it for synchronization. It is possible to transmit using a number of subcarriers, it is possible to improve the frequency spectrum efficiency compared to the conventional technique.

According to an embodiment, the data transmission apparatus 10 of the present invention may include a resource setting unit 100, a modulator, and a communication unit 400. For example, the data transmission apparatus 10 may modulate a synchronization sequence for removing inter-symbol interference of a data symbol and a data symbol to be transmitted, and transmit the modulated modulation symbols and the preamble by overlapping them on the time axis. The data transmission apparatus 10 of the present invention may modulate a synchronization sequence for removing inter-symbol interference between a data symbol and a data symbol by integrating the first modulator 200 and the second modulator 300 into a modulator. .

For example, as an embodiment of the present invention, a case in which the data transmission apparatus 10 combines the first modulator 200 and the second modulator 300 to transmit data using the modulator and the communication unit will be described. . The modulator generates at least one modulation symbol by inverse Fourier transforming a data symbol to be transmitted and a synchronization sequence for removing intersymbol interference of the data symbol based on at least one filter having a predetermined frequency response. In the present invention, inverse Fourier transform based on at least one filter having a preset frequency response is based on a filter bank multicarrier (FBMC) scheme based on a filter having a preset frequency response and subcarriers of different frequency bands. It includes.

The data symbols to be transmitted by the data transmission apparatus 10 of the present invention include raw data or offset quadrature amplitude modulated (OQAM) data symbols or quadrature amplitude modulated (QAM) data symbols modulated. For example, the data symbol of the present invention applies an offset to one of a real part or an imaginary part arranged at predetermined intervals, and transmits the real component and the imaginary component of the QAM symbol by half a period, and modulates the offset. Offset Quadrature Amplitude Modulation (OQAM) data symbols or Quadrature Amplitude Modulation (QAM) data symbols.

The resource setting unit 100 presets a transmission resource for transmitting a data symbol, the synchronization sequence, and the preamble. For example, the transmission resource set by the resource setting unit 100 may include at least one of a data symbol, a frequency characteristic of a subcarrier for transmitting the synchronization sequence, and a time domain in which the preamble is transmitted. For example, when the resource setting unit 100 selects a frequency domain of a subcarrier as a frequency characteristic of a subcarrier to which a preamble is transmitted and a subcarrier to transmit a synchronization sequence, the first modulator 200 and the second modulator 300 are selected. May use this to generate a first modulation symbol and a second modulation symbol. The resource setting unit 100 of the present invention is not provided separately, and may be provided in the modulator, the first modulator 200, and the second modulator 300, respectively, to perform the same function. It demonstrates with reference to FIG.

For example, in selecting a time domain in which the preamble is to be transmitted, the resource setting unit 100 may select a region having a large coefficient in consideration of an impulse response of a prototype filter. The resource setting unit 100 minimizes power attenuated by the prototype filter in the filtering process by effectively setting a time domain for transmitting the preamble to the region 152 having a large coefficient size of the prototype filter, and effectively suppresses the overlapping interference components. Can be removed It demonstrates with reference to FIG.

For example, in setting a frequency characteristic of a subcarrier for transmitting a synchronization sequence, the resource setting unit 100 sets subcarrier sets 162, 164, 166, and 168 having the same interval in a frequency domain as subcarrier regions. It is possible to prevent the power of the synchronization sequence from becoming too large. Prototype filter in the present invention may be provided with PHYDYAS widely used in the FBMC communication system. It demonstrates with reference to FIG.

The first modulator 200 includes a mapping unit 220 and a first frequency inverse converter 240. For example, the first modulator 200 generates a first modulation symbol by inverse Fourier transforming the data symbols based on the filter. For example, when the first modulator 200 and the second modulator 300 are integrated into a modulator to perform a data transmission device, the modulation symbols include first modulated symbols. The first modulator 200 generates a first modulation symbol by inverse Fourier transform based on a filter, based on a filter bank multicarrier based on a filter having a preset frequency response and subcarriers of different frequency bands. Generating a first modulation symbol in an FBMC) manner.

The mapping unit 220 maps data symbols to subcarriers having different frequency bands. The data transmission apparatus 10 according to an embodiment of the present invention uses a multi-carrier and transmits the bandwidth of a carrier to be divided into a plurality of sub-channels, thereby efficiently using frequency resources.

The first frequency inverse converter 240 convolves a data symbol mapped to the subcarrier on a frequency axis with a prototype filter, which is a filter having the preset frequency response, and the data convolved with the prototype filter. Inverse Fourier transform the symbol. For example, the first frequency inverse converter 240 may further include oversampling the mapped data symbol by a filter order before convolving the mapped data symbol with the prototype filter. The first frequency inverse converter 240 convolves a data symbol mapped to a subcarrier in a prototype filter and a frequency axis, and performs Fourier inverse conversion, which includes an FBMC modulation process. It demonstrates with reference to FIG.

The second modulator 300 includes an interference inducer 320, a selector 340, a synchronization sequence inducer 360, and a second frequency inverse converter 380. For example, the second modulator 300 induces a synchronization sequence for removing intersymbol interference of the first modulation symbol in the time domain in which the preamble is transmitted, and inverses the derived synchronization sequence based on the filter. Fourier transform to generate a second modulation symbol. For example, when the data transmission apparatus 10 generates a modulation symbol by using a modulator including the first modulator 200 and the second modulator 300, the generated modulation symbol may be a second modulation symbol. Include.

The interference induction unit 320 induces inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted. For example, the interference inducing unit 320 may induce inter-symbol interference of the first modulation symbols derived by overlapping the first modulation symbols generated by modulating the data symbols on the time axis. Although the interference induction unit 320 according to an embodiment of the present invention may be included in the second modulator 300 to induce inter-symbol interference due to the superposition of the first modulation symbol, it is included in the first modulator 200. And to induce inter-symbol interference due to overlap of the first modulation symbol. The selector 340 selects a subcarrier region for transmitting the derived synchronization sequence. For example, the subcarrier region selected by the selector 340 may be transmitted to the synchronization sequence deriving unit 360 along with a time region for transmitting the preamble set by the resource setting unit 100.

The synchronization sequence derivation unit 360 derives a synchronization sequence for removing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted. In the conventional FBMC system, interference may occur between FBMC symbols in an overlap and sum process on a time axis, and the generated interference may adversely affect a preamble-based synchronization process. Therefore, a synchronization sequence for eliminating interference between FBMC symbols may be derived and transmitted in an overlapping manner in the data transmission process to remove or reduce an interference component. It demonstrates with reference to FIG. For example, the synchronization sequence deriving unit 360 removes an interference component overlapping a time domain for transmitting the preamble based on the following equation relationship using a time domain for transmitting the set preamble and a subcarrier region for transmitting the selected synchronization sequence. You can derive the sequence.

Unlike the conventional technique for deriving a synchronization sequence, the synchronization sequence deriving unit 360 according to the present invention uses a time domain in which a preamble is set to be a length adjustable sequence and a subcarrier region for transmitting a synchronization sequence as variables. By inducing a synchronization sequence by using an inverse process of the included FBMC modulation process, efficiency of the frequency spectrum of the data transmission apparatus 10 may be improved.

는 FBMC-OQAM시스템의 Effective channel 행렬로서, FBMC 변조 과정을 의미하는 행렬(364), di는 i번째 OQAM 심볼 벡터로서 본 발명에서는 직교 진폭 변조된 데이터 심볼(366)을 의미한다.Here, Xn is a transmission signal 362 generated by the data transmission apparatus 10 of the present invention by superimposing a first modulation symbol, a second modulation symbol, and a preamble, i is an arbitrary integer,

Denotes an effective channel matrix of the FBMC-OQAM system, a matrix 364 representing an FBMC modulation process, and di denotes an i-th OQAM symbol vector, and in the present invention, a quadrature amplitude modulated data symbol 366.

는 제1 변조 심볼의 심볼간 간섭(370),

,

은 FBMC-OQAM 시스템의 Effective Channel 행렬(364)을 의미한다. 상기 데이터 송신 장치(10)가 송신하는 송신 신호(362)를 실수 및 허수부를 포함하는 복소 성분으로 변환하면 하기 수학식 3과 같다.Here, x _n is a transmission signal 362 generated by the data transmission apparatus 10 of the present invention by superimposing a first modulation symbol, a second modulation symbol, and a preamble. The index of the data symbol, d _n is the n th data symbol 366, dn + 1 is the n + 1 th data symbol 366,

Intersymbol interference 370 of the first modulation symbol,

,

Denotes an Effective Channel matrix 364 of the FBMC-OQAM system. When the transmission signal 362 transmitted by the data transmission device 10 is converted into a complex component including a real number and an imaginary part, the following equation (3) is obtained.

은 제1 변조 심볼의 심볼간 간섭(ISI, 370)의 실수 성분,

은 제1 변조 심볼의 심볼간 간섭(ISI, 370)의 허수 성분을 의미한다.Where Re {X _n } is a real component of the transmission signal 362 transmitted by the data transmission apparatus 10, Im {X _n } is an imaginary component of the transmission signal transmitted by the data transmission apparatus 10, n and n +1 is any integer, d _n is the n th data symbol 366, d _{n + 1} is the n + 1 th data symbol 366,

Is a real component of intersymbol interference (ISI) 370 of the first modulation symbol,

Denotes an imaginary component of intersymbol interference (ISI) 370 of the first modulation symbol.

은 프리앰블을 송신하는 시간 영역(366에서 368의 영역),

는 동기 시퀀스를 송신할 부반송파 영역,

는 프리앰블을 송신하는 시간 영역에서 송신 신호(362)의 실수 성분,

는 프리앰블을 송신하는 시간 영역에서 송신 신호(362)의 허수 성분,

는 동기 시퀀스(368)를 송신하기 위한 부반송파 영역에서의 n번째 데이터 심볼로 표기되는 동기 시퀀스,

는 동기 시퀀스(368)를 송신하기 위한 부반송파 영역에서의 n+1번째 데이터 심볼로 표기되는 동기 시퀀스,

는 프리앰블을 전송할 시간 영역에서 제1 변조 심볼의 간섭 성분(370)의 실수 성분,

는 프리앰블을 전송할 시간 영역에서 제1 변조 심볼의 간섭 성분(370)의 허수 성분,

,

,

및

는 해당 부반송파 전송 영역 및 프리앰블을 송신할 시간 영역에서의 FBMC-OQAM 시스템의 Effective Channel 행렬(364)의 실수 및 허수 성분을 의미한다. 상기 수학식 4에서

및

로 표현되는 선택된 부반송파 영역에서의 n, n+1번째 데이터 심볼로 표기되는 동기 시퀀스를 역 행렬을 사용하여 구하면 하기 수학식 5와 같다.From here,

Is the time domain in which to transmit the preamble (from 366 to 368),

Is a subcarrier area to transmit a synchronization sequence,

Is the real component of the transmission signal 362 in the time domain for transmitting the preamble,

Is an imaginary component of the transmission signal 362 in the time domain for transmitting the preamble,

Is a synchronization sequence denoted by the nth data symbol in the subcarrier region for transmitting the synchronization sequence 368,

Is a synchronization sequence indicated by the n + 1 th data symbol in the subcarrier region for transmitting the synchronization sequence 368,

Is a real component of the interference component 370 of the first modulation symbol in the time domain to transmit the preamble,

Is an imaginary component of the interference component 370 of the first modulation symbol in the time domain in which to transmit the preamble,

,

,

And

Denotes real and imaginary components of the effective channel matrix 364 of the FBMC-OQAM system in the corresponding subcarrier transmission region and the time domain in which the preamble is to be transmitted. In Equation 4

And

A synchronization sequence represented by an n, n + 1 th data symbol in a selected subcarrier region represented by λ is obtained using an inverse matrix as shown in Equation 5 below.

는 동기 시퀀스를 송신하기 위한 부반송파 영역에서의 n번째 데이터 심볼로 표기되는 동기 시퀀스(368),

는 동기 시퀀스를 송신하기 위한 부반송파 영역에서의 n+1번째 데이터 심볼로 표기되는 동기 시퀀스(368),

,

,

및

는 해당 부반송파 전송 영역 및 프리앰블을 송신할 시간 영역에서의 FBMC-OQAM 시스템의 Effective Channel 행렬(364)의 실수 및 허수 성분,

는 프리앰블을 송신하는 시간 영역에서 송신 신호(362)의 실수 성분,

는 프리앰블을 송신하는 시간 영역에서 송신 신호(362)의 허수 성분,

는 프리앰블을 전송할 시간 영역에서 제1 변조 심볼의 간섭 성분(370)의 실수 성분,

는 프리앰블을 전송할 시간 영역에서 제1 변조 심볼의 간섭 성분(370)의 허수 성분을 의미한다. 상기 수학식 5에서 FBMC-OQAM 시스템의 Effective Channel 행렬(364)의 역행렬을 이용하여

및

를 유도하는 것은 도 6에 도시된 프리앰블을 전송할 시간 영역 및 선택된 부반송파 영역에서의 간섭 성분을 제거하는 동기 시퀀스(368)을 유도하는 과정과 같다.From here,

Is a synchronization sequence 368 denoted by an nth data symbol in a subcarrier region for transmitting a synchronization sequence,

Is a synchronization sequence 368 denoted by the n + 1 th data symbol in the subcarrier region for transmitting a synchronization sequence,

,

,

And

The real and imaginary components of the effective channel matrix 364 of the FBMC-OQAM system in the corresponding subcarrier transmission region and the time domain to transmit the preamble,

Is the real component of the transmission signal 362 in the time domain for transmitting the preamble,

Is an imaginary component of the transmission signal 362 in the time domain for transmitting the preamble,

Is a real component of the interference component 370 of the first modulation symbol in the time domain to transmit the preamble,

Denotes an imaginary component of the interference component 370 of the first modulation symbol in the time domain in which the preamble is to be transmitted. In Equation 5, the inverse of the effective channel matrix 364 of the FBMC-OQAM system is used.

And

Deriving is similar to a process of deriving a synchronization sequence 368 for removing interference components in a time domain to transmit a preamble and a selected subcarrier region shown in FIG. 6.

For example, a process of obtaining a synchronization sequence derived when the data transmission apparatus 10 of the present invention uses the FBMC-QAM system may be expressed by the following equation.

및

는 FBMC-QAM시스템의 Effective channel 행렬로서, FBMC 변조 과정을 의미하는 행렬(364),

는 짝수 번째 부반송파에 실린 i번째 데이터 심볼,

는 홀수 번째 부반송파에 실린 i번째 데이터 심볼을 의미한다. 여기에서 심볼간 간섭(ISI)성분을 반영하면 하기의 수학식 7과 같다.X _n is a transmission signal 362 generated by the data transmission apparatus 10 of the present invention by superimposing a first modulation symbol, a second modulation symbol, and a preamble, and i is an arbitrary integer,

And

Is an effective channel matrix of the FBMC-QAM system, a matrix (364) indicating an FBMC modulation process,

Is the i th data symbol on the even subcarrier,

Denotes an i th data symbol carried on an odd subcarrier. In this case, when the intersymbol interference (ISI) component is reflected, it is represented by Equation 7 below.

는 짝수번째 부반송파에 실린 n번째 QAM 심볼 벡터,

홀수번째 부반송파에 실린 n번째 QAM 심볼 벡터,

는 제1 변조 심볼의 심볼간 간섭,

및

는 해당 부반송파 전송 영역 및 프리앰블을 송신할 시간 영역에서의 FBMC-QAM 시스템의 Effective Channel 행렬을 의미한다. 상기 수학식 7에서 동기 시퀀스를 송신할 부반송파 영역

와 프리앰블을 송신할 시간 영역

을 대입하여 역행렬의 곱을 통한 동기 시퀀스를 유도하면 하기 수학식 8과 같다.Here, X _n is a transmission signal 362 generated by the data transmission apparatus 10 of the present invention by superimposing a first modulation symbol, a second modulation symbol and a preamble,

Is the nth QAM symbol vector on the even subcarrier,

The nth QAM symbol vector on the odd subcarrier,

Is the intersymbol interference of the first modulation symbol,

And

Denotes an effective channel matrix of an FBMC-QAM system in a corresponding subcarrier transmission region and a time domain in which a preamble is to be transmitted. Subcarrier region to transmit a synchronization sequence in Equation (7)

Time zone to transmit the preamble

Deriving the synchronization sequence through the product of the inverse matrix by substituting the following equation (8).

는 동기 시퀀스를 송신할 부반송파 영역,

는 프리앰블을 송신할 시간 영역,

는 부반송파 영역

에서 짝수 번째 부반송파에 실린 n번째 데이터 심볼로 표현되는 동기 시퀀스,

는 상기 수학식 7에서 해당 부반송파 전송 영역 및 프리앰블을 송신할 시간 영역에서의 FBMC-QAM 시스템의 Effective Channel 행렬의 역 행렬,

는 프리앰블을 전송할 시간 영역에서 송신 신호,

는 프리앰블을 전송할 시간 영역에서의 심볼간 간섭을 의미한다.From here,

Is a subcarrier area to transmit a synchronization sequence,

Is a time domain for transmitting the preamble,

Is the subcarrier region

A synchronization sequence represented by the n th data symbol on an even subcarrier in

Is an inverse matrix of the effective channel matrix of the FBMC-QAM system in the time domain in which the corresponding subcarrier transmission region and the preamble are transmitted in Equation 7,

Is a transmission signal in the time domain to transmit the preamble,

Means inter-symbol interference in the time domain in which the preamble is to be transmitted.

The synchronization sequence derivation unit 360 derives a synchronization sequence for removing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted.

The second frequency inverse transform unit 380 convolves the synchronization sequence mapped to the subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter which is a filter having a preset frequency response. Inverse Fourier transform the convolutional sequence with and. For example, the process of the second frequency inverse transform unit 380 convolving on the frequency axis using a prototype filter which is a filter having a preset frequency response, and performing inverse Fourier transform (IFFT) on the convoluted sync sequence are described above. As such, it may be provided in an FBMC modulation scheme. Accordingly, the second modulator 300 induces the synchronization sequence by using the selected subcarrier region, the time domain in which the preamble is transmitted, and the inter-symbol interference (ISI) overlapping in the time domain, and convolution with the prototype filter. And generate the second modulation symbol by using the inverse Fourier transformed synchronization sequence.

The first modulator 200 and the second modulator 300 of the present invention are a frequency domain FBMC representation technique for generating the first modulated symbol and the second modulated symbol, and include at least one filter having a preset frequency response. Based on the above, the method of convolving the prototype filter with the frequency axis and using the method of inverse Fourier transforming the data symbol convolved with the prototype filter is as described above. In addition, the first modulator 200 and the second modulator 300 may perform the same process for generating the first modulation symbol and the second modulation symbol in addition to the above-described Frequency Domain FBMC representation scheme. A first modulation symbol and a second modulation symbol may be generated using a filer-bank-Form based on or a time domain FBMC representation technique based on a filter frequency response in the time domain.

The communication unit 400 transmits the generated modulation symbols and the preamble for synchronizing the data symbols by overlapping them on the time axis. For example, the communication unit 400 may transmit a modulation symbol including a first modulation symbol and a second modulation symbol and a preamble overlapping each other on a time axis to the receiver. The communicator 400 transmits a first modulation symbol, a second modulation symbol, and a preamble by overlapping in a time domain in which the preamble is transmitted, wherein a subcarrier for transmitting a synchronization sequence is a set of subcarriers having the same interval in a frequency domain. Can be prepared as.

In the present invention, overlapping at least one of the first modulation symbol, the second modulation symbol, and the preamble on the time axis by the first modulator 200 and the communicator 400 includes an overlap & sum process. For example, the communication unit 400 superimposes the first modulation symbol, the second modulation symbol, and the preamble on the time axis in consideration of the number of data symbols to be transmitted and the filter order of the prototype FilterOrder. An interval between the first modulation symbol, the second modulation symbol, and the preamble may be set. In addition, the length of the preamble used by the communication unit 400 for the overlap may be provided in a sequence that can be adaptively adjusted in length.

The data transmission apparatus 10 of the present invention does not use the entire FBMC symbol to derive the synchronization sequence, but rather derives and overlaps the synchronization sequence for removing the inter-symbol interference component overlapping in the time domain for transmitting the preamble. As described above, even if a small number of subcarriers is used, frequency spectrum efficiency can be improved by using a new synchronization technique capable of generating a desired type of preamble in a specific time domain.

FIG. 2 is an exemplary diagram illustrating a method of determining a time domain for transmitting a preamble among transmission resources set by a resource setting unit in the embodiment of FIG. 1.

The resource setting unit 100 may determine a time domain for transmitting the preamble as a transmission resource, and select a time domain for transmitting the preamble as an area having a large coefficient in consideration of an impulse response of the prototype filter. By selecting the time domain in which the resource setting unit 100 transmits the preamble in consideration of the impulse response of the prototype filter, the data transmission apparatus 10 minimizes the power attenuated by the prototype filter during the filtering process, The fact that the interference component can be effectively removed is as described above and thus omitted.

3 is an exemplary diagram illustrating a frequency interval of a subcarrier for transmitting a synchronization sequence by a resource setting unit in the embodiment of FIG. 1.

The resource setting unit 100 presets a transmission resource for transmitting a data symbol, a synchronization sequence, and a preamble. The resource setting unit 100 according to an exemplary embodiment may set the same interval of subcarriers for transmitting a synchronization sequence. For example, the resource setting unit 100 may set the same interval of subcarriers, but may set one subcarrier interval per two data symbols or one subcarrier interval per four data symbols.

FIG. 4 is an enlarged block diagram of the first modulator 200 in the embodiment of FIG. 1.

The first modulator 200 includes a mapping unit 220 and a first frequency inverse transform unit 240. For example, the first modulator 200 may generate a first modulation symbol by FBMC-modulating the data symbol. In more detail, the first modulator 200 of the present invention may generate a first modulation symbol using an FBMC-OQAM method or an FBMC-QAM method using an OQAM symbol or a QAM symbol as a data symbol to be transmitted. have.

FIG. 5 is an enlarged block diagram of the second modulator 300 in the embodiment of FIG. 1.

The second modulator 300 includes an interference inducer 320, a selector 340, a synchronization sequence inducer 360, and a second frequency inverse converter 380. For example, the second modulator 300 induces inter-symbol interference of the first modulation symbol in the time domain where the preambles overlap, and FBMC modulates a synchronization sequence for removing the induced inter-symbol interference to generate the second modulation symbol. Can be generated. The second modulator 300 may transmit a data symbol using an FBMC-OQAM or FBMC-QAM scheme to transmit an offset orthogonal modulated symbol (OQAM) data symbol or an orthogonal modulation symbol (QAM) as a data symbol. .

FIG. 6 is a reference diagram illustrating a process for inducing a sync sequence by the sync sequence inducing unit in the embodiment of FIG. 5.

The transmission signal transmitted by the data transmission apparatus 10 of the present invention is referred to as y (362), and A (364) includes data including an effective channel matrix of the FBMC-QAM system and a synchronization sequence for transmitting x (366). If the symbol, b 370, is intersymbol interference (ISI), a relation of y = Ax + b is satisfied. Here, the synchronization sequence 368 included in x may be derived using the inverse of the effective channel of the FBMC-QAM system. In the present invention, a detailed method of obtaining a synchronization sequence derived by the synchronization sequence inducing unit 360 in the time domain to transmit the preamble and the selected subcarrier region is the same as described above, and thus will be omitted.

7 is a reference diagram illustrating a result of comparing correlation between a transmission signal and a preamble according to an embodiment of the present invention.

When the data transmission apparatus 10 of the present invention derives a synchronization sequence for eliminating inter-symbol interference (ISI) of the first modulation symbol and overlaps the preambles, the data transmission apparatus 10 generates a synchronization sequence for generating a preamble instead of a correlation ( Even if some subcarriers are used by guaranteeing the Correlation property, it is possible to achieve excellent Spectral Efficiency (compared to conventional synchronization technology). For example, the data transmission apparatus 10 according to the present invention has 1024 subcarriers, an oversampling factor of 4, a prototype filter of a PHYDYAS filter, and a sequence for a preamble is a Zadoff-Chu Sequence (128 length). ), A better correlation between the transmission signal and the preamble can be ensured by deriving a synchronization sequence for removing the ISI and overlapping the preambles.

8 is an exemplary view illustrating a process of a data transmission method according to an embodiment of the present invention.

If a data transmission method performed by the data transmission apparatus 10 according to an embodiment of the present invention is briefly illustrated as a graph, it may be represented by the process illustrated in FIG. 8. For example, the data transmission apparatus 10 of the present invention uses a prototype filter 358 having a preset frequency response of a data sequence 368 and a synchronization sequence for removing inter-symbol interference (ISI) of the first modulation symbol. Based on FBMC modulation, a first modulation symbol and a second modulation symbol may be generated. The data transmission apparatus 10 sets a time domain for transmitting a preamble and transmits the preamble 408 by overlapping the set time domain, thereby transmitting a signal 412 including a synchronization sequence and a preamble component for removing intersymbol interference. Can be sent to the receiving end.

9 is a block diagram of an apparatus 20 for receiving data according to an embodiment of the present invention.

The data receiving apparatus 20 of the present invention includes a synchronizer 500, a channel estimator 600, a preamble remover 700, and a data symbol detector 800. For example, the data receiving apparatus 20 obtains synchronization from a transmission signal in which the first modulation symbol, the second modulation symbol, and the preamble transmitted from the data transmission apparatus 10 are superimposed on the time axis, and the synchronization is obtained. The preamble is removed from the transmission signal, and the data symbol to be transmitted can be detected by the transmitter by FBMC demodulation (FBMC) demodulation. The transmission signal received by the data receiving apparatus 20 of the present invention includes a modulation symbol, and more particularly, a modulation symbol modulated by the FBMC modulation scheme.

The synchronization unit 500 obtains synchronization of the modulation symbols based on cross correlation of modulation symbols in which at least one data symbol received from a transmitter is modulated and a preamble for synchronization of the data symbols. For example, the synchronizer 500 includes at least one correlator, and performs cross-correlation between the received modulation symbol and the preamble using the correlator to acquire synchronization of the received modulation symbol. can do. The synchronization unit 500 of the present invention outputs an FBMC modulation symbol obtained with synchronization in a time or frequency domain based on the obtained synchronization.

The channel estimator 600 estimates the state of the channel by calculating an impulse response according to the frequency characteristic of the channel through which the modulation symbols are transmitted. For example, the channel estimator 600 calculates an impulse response according to a natural frequency characteristic of a channel through which data is transmitted between a transmitter and a receiver, and indicates a state of a channel based on the calculated impulse response. Can be.

The preamble remover 700 obtains a preamble that has passed through the channel based on an impulse response according to a natural frequency characteristic of a channel through which the modulation symbols are transmitted and a convolution operation of the preamble in the modulation symbols obtained from the synchronization, and the modulation symbol The preamble is removed from the modulation symbols by referring to the synchronization of the two symbols. For example, the preamble remover 700 according to the present invention uses the impulse response of the channel calculated by the channel estimator 600 to refer to synchronization of the preambles superimposed on the time domain to transmit the modulation symbols. Remove from the field. It demonstrates with reference to FIG.

The data symbol detector 800 includes a demodulator 820 and a demapping unit 840. For example, the data symbol detector 800 detects the data symbols by Fourier transforming the modulation symbols from which the preamble is removed based on at least one filter having a preset frequency response. In the present invention, Fourier transforming of the data symbol detector 800 based on at least one filter having a predetermined frequency response is performed by using a demodulation technique according to a filter bank multicarrier (FBMC) scheme. can do.

The demodulator 820 performs Fourier transform on the modulation symbols from which the preamble has been removed in consideration of the frequency response of the filter, and uses different filter weights of a prototype filter that is a filter having a preset frequency response. Demodulate the Fourier transformed modulation symbols. For example, the demodulator 820 may demodulate modulation symbols by performing FBMC demodulation using different weights according to filter characteristics of the prototype in the FBMC communication system. The demapping unit 840 demaps the demodulated modulation symbols mapped to subcarriers having different frequency bands to different frequency bands of the subcarriers. For example, the demapping unit 840 demodulates FBMC modulated modulation symbols by mapping the data symbols to subcarriers having different frequency bands at the transmitting side, and demodulating the demodulated modulation symbols mapped to the subcarriers. Demap to different frequency bands of subcarriers.

FIG. 10 is an enlarged block diagram of a data symbol detector in the embodiment of FIG. 9.

The data symbol detector 800 includes a demodulator 820 and a demapping unit 840. The process of demodulating the modulation symbols by the data symbol detection unit 800 and demapping them to different frequency bands is the same as described above.

11 is a flowchart illustrating a data transmission method according to an embodiment of the present invention.

The data transmission method performed by the data transmission apparatus 10 in the present invention includes the following time series steps.

In S100, the resource setting unit 100 presets a transmission resource for transmitting the data symbol, the synchronization sequence and the preamble. For example, the transmission resource set by the resource setting unit 100 includes at least one of a data symbol, a frequency characteristic of a subcarrier for transmitting the synchronization sequence, and a time domain in which the preamble is transmitted. In addition, the resource setting unit 100 effectively removes overlapping interference components by setting a time domain in a region having a large coefficient in consideration of the impulse response of the prototype filter, and by the prototype filter in the filtering process. As described above, the power attenuated can be minimized.

In S200, the first modulator 200 generates a first modulation symbol by inverse Fourier transforming the data symbol based on the filter. For example, the first modulator 200 may generate a first modulation symbol by modulating a data symbol to be transmitted using the FBMC-OQAM technique. For example, the first modulation symbol generated by the first modulation unit 200 includes an FBMC modulation symbol. In addition, the first modulator 200 may generate a first modulation symbol by modulating a data symbol to be transmitted using the FBMC-QAM technique. The data symbol to be transmitted used by the first modulator 200 of the present invention includes an offset quadrature amplitude modulation (OQAM) or quadrature amplitude modulation (QAM) modulated data symbol.

In S300, the second modulator 300 derives a synchronization sequence for removing inter-symbol interference of the first modulation symbol in the time domain in which the preamble is transmitted, and inversely Fourier based on the filter, the derived synchronization sequence. The transform generates a second modulation symbol. For example, the second modulator 300 calculates the intersymbol interference of the overlapping FBMC modulation symbols in the time domain in which the preamble is transmitted, derives a synchronization sequence for eliminating the calculated intersymbol interference, and derives the derived synchronization sequence. FBMC may generate a second modulation symbol by FBMC modulation. The data symbols used by the second modulator 300 include offset quadrature amplitude modulation (OQAM) or quadrature amplitude modulation (QAM) modulated data symbols. Further, in the present invention, inverse Fourier transform based on at least one filter having a preset frequency response may include a filter bank multicarrier (FBMC) based on a filter having a preset frequency response and subcarriers of different frequency bands. Includes a modulation method using the

In S400, the communication unit 400 transmits a first modulation symbol, the generated second modulation symbol, and the preamble by overlapping the time axis. For example, the communication unit 400 overlapping the first modulation symbol, the second modulation symbol, and the preamble on the time axis includes an overlap & sum process. The interval at which the communication unit 400 overlaps the first modulation symbol, the second modulation symbol, and the preamble on the time axis may be set in consideration of the number of data symbols and a filter order to be transmitted. By transmitting a transmission signal in which the first modulation symbol, the second modulation symbol, and the preamble are superimposed through the overlap & sum structure in the communication unit 400, the data transmission apparatus 10 may secure orthogonality between different symbols. Can be.

FIG. 12 is an enlarged flowchart of generating a first modulation symbol in the embodiment of FIG. 11.

In S220, the mapping unit 220 maps data symbols to be transmitted to subcarriers having different frequency bands. For example, the mapping unit 220 maps data symbols to a plurality of subcarriers in order to use multiple subcarriers having adjacent frequency bands according to the FBMC scheme, and spaces the same on the frequency domain of the subcarriers used for mapping. Can be.

In S240, the first frequency inverse converter 240 convolves a data symbol mapped to a subcarrier on a frequency axis with a prototype filter, which is a filter having the preset frequency response, and convolved with the prototype filter. Inverse Fourier transform the data symbols. For example, the process of the first frequency inverse transform unit 240 convolving on the frequency axis using a filter having a preset frequency response, and the inverse Fourier transform of the data symbol convolved with the filter include an FBMC modulation scheme.

FIG. 13 is an enlarged flowchart of generating a second modulation symbol in the embodiment of FIG. 11; FIG.

In S320, the interference inducing unit 320 induces inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted. For example, the interference inducing unit 320 may induce inter-symbol interference of the first modulation symbols derived by overlapping the first modulation symbols generated by modulating the data symbols on the time axis. In S340, the selector 340 selects a subcarrier region for transmitting the derived synchronization sequence.

In S360, the synchronization sequence deriving unit 360 derives a synchronization sequence for removing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted. The synchronization sequence deriving unit 360 may derive the synchronization sequence according to Equation 1 to Equation 8 represented by the FBMC Effective Channel matrix using a time domain in which the set preambles overlap and a selected subcarrier region.

In operation S380, the second frequency inverse transform unit 380 convolves the synchronization sequence mapped to a subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter that is a filter having a preset frequency response. Inverse Fourier transform the sync sequence convolved with a prototype filter. As described above, the process of convoluting a prototype filter having a preset frequency response and a frequency axis and inverse Fourier transforming a convolutional sequence convolved with the prototype filter includes the FBMC modulation scheme.

14 is a flowchart illustrating a data receiving method according to an embodiment of the present invention.

The data receiving method performed by the data receiving apparatus 20 of the present invention includes the following steps performed in time series.

In S500, the synchronization unit 500 obtains synchronization of the modulation symbols based on cross-correlation of modulation symbols in which at least one data symbol received from a transmitter is modulated and a preamble for synchronization of the data symbols. do. A detailed method of acquiring synchronization of the modulation symbols received from the transmitter by the synchronizer 500 is as described above. In S600, the channel estimator 600 estimates the state of the channel by calculating an impulse response according to the frequency characteristic of the channel through which the modulation symbols are transmitted. Estimating the state of the channel by the channel estimator 600 includes calculating a impulse response reflected in the unique frequency characteristic of each channel.

In S700, the preamble removing unit 700 removes the preamble from the modulation symbols based on the impulse response of the channel through which the modulation symbols are transmitted and the convolution operation of the preamble. For example, the preamble remover 700 may remove the preambles transmitted by the data transmission apparatus 10 for signal synchronization on the time axis, and output the preambles to the data symbol detector 800. In S800, the data symbol detector 800 detects the data symbols by Fourier transforming the modulation symbols from which the preamble is removed based on at least one filter having a preset frequency response. As described above, the data symbol detection unit 800 detects the data symbol by demodulating the modulation symbols from which the preamble is removed.

15 is an enlarged flowchart of detecting data symbols in the embodiment of FIG. 14.

In S820, the demodulator 820 performs Fourier transform on the modulation symbols from which the preamble is removed in consideration of the frequency response of the filter, and different weights of the prototype filter, which is a filter having a preset frequency response. Demodulate the Fourier transformed modulation symbols. For example, as described above, the demodulator 820 may demodulate the modulation symbols from which the preamble is removed by using an FBMC demodulation technique. In S840, the demapping unit 840 demaps the demodulated modulation symbols mapped to subcarriers having different frequency bands to different frequency bands of the subcarriers. A detailed method of demapping the demodulated modulation symbols to different frequency bands by the demapping unit 840 is as described above, and thus will be omitted.

16 is a reference diagram comparing the performance of the data transmission apparatus 10 according to the type and length of the preamble.

When the data transmission apparatus 10 of the present invention transmits data symbols under the FBMC-OQAM or FBMC-QAM system, performance according to the length of the preamble will be described below. The resource setting unit 100 may set, as a preamble, a sequence having a good correlation characteristic and an adaptively adjustable length to configure a transmission FBMC signal, and the sequence for setting the preamble is a Zadoff-Chu sequence 902. 904 and 906 and PN sequences 908, 910 and 912. The sequence for preamble setting set by the resource setting unit 100 of the present invention is not limited to the above-described Zadoff-Chu sequences 902, 904, and 906 and PN sequences 908, 910, and 912. It can be set using other known sequences considering the correlation characteristics. In order to measure the performance according to the preamble type and length of the data transmission apparatus 10 of the present invention, the RMSE and BER according to the simulation result SNR under 1024 subcarriers, 1024 data symbols, oversampling factor 4 and Ped-A-Channel are As shown in FIG. As the length of the preamble used by the data transmission apparatus 10 increases, root mean square deviation (RMSE) converges at a low SNR, and as the length of the preamble is short, the RMSE converges at a high SNR. However, when the preamble is set using a long sequence, the data transmission apparatus 10 may require a large number of subcarriers, and as a result, the frequency efficiency may be reduced. In the case of the bit error rate (BER) of the data transmission apparatus 10 according to the present invention, the performance difference according to the length and type of the preamble is not large, and the consistent BER characteristic according to the SNR variation is shown.

17 is a reference diagram comparing the performance of the data transmission apparatus 10 according to the type and length of the preamble.

When the data transmission apparatus 10 of the present invention transmits data symbols under the FBMC-QAM system, the performance according to the length of the preamble is compared with FIG. 17. As the data transmission apparatus 10 transmits data symbols under the FBMC-OQAM system, as the length of the preamble is longer, the RMSE converges at a lower SNR, and the BER performance may be observed that the change according to the length of the preamble is not large. . Therefore, the data transmission apparatus 10 of the present invention preferably sets the type and length of the appropriate preamble according to the system environment in order to improve the frequency efficiency.

Table 1 shows the resource utilization rate of the present invention according to the preamble length. In order to compare the resource utilization rates of the data transmission apparatus 10 and the data receiving apparatus 20, simulation was performed by setting 1024 subcarriers and the number of data symbols to 10. As a result, the conventional technique shows that the resource utilization for synchronization is 10%. In the proposed invention, when the preamble length is 128, 256, and 512, the resource utilization rate is 1.25%, 2.5%, and 5%, respectively. Accordingly, the data transmission apparatus 10 and the data reception apparatus 20 according to the present invention have an advantage of improving frequency efficiency by applying a preamble that is adaptively adjustable in length to a synchronization process.

All or part of the method of one embodiment of the present invention described above may be implemented in the form of a computer-executable recording medium (or a computer program product), such as a program module executed by a computer. Here, the computer readable medium may include a computer storage medium (eg, memory, hard disk, magnetic / optical media or solid-state drive, etc.). Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media.

In addition, all or part of the method according to an embodiment of the present invention includes instructions executable by a computer, the computer program including programmable machine instructions processed by a processor, and a high-level programming language. Language, an object-oriented programming language, an assembly language, or a machine language.

Means or modules in the present specification may mean hardware capable of performing functions and operations according to each name described in the present specification, and computer program code capable of performing specific functions and operations. It may also mean an electronic recording medium, for example, a processor or a microprocessor, on which computer program code capable of performing specific functions and operations may be implemented. In other words, a means or module may mean a functional and / or structural combination of hardware for performing the technical idea of the present invention and / or software for driving the hardware.

Thus, a method according to an embodiment of the present invention may be implemented by executing a computer program as described above by a computing device. The computing device may include at least some of a processor, a memory, a storage device, a high speed interface connected to the memory and a high speed expansion port, and a low speed interface connected to the low speed bus and the storage device. Each of these components are connected to each other using a variety of buses and may be mounted on a common motherboard or otherwise mounted in a suitable manner.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (23)

A modulator for inversely Fourier transforming a data symbol to be transmitted and a synchronization sequence for removing intersymbol interference of the data symbol based on at least one filter having a predetermined frequency response to generate at least one modulation symbol; And
A communication unit for superimposing and transmitting the generated modulation symbols and a preamble for synchronization of the data symbols on a time axis; Including;
The modulator includes a first modulator for generating a first modulated symbol by inverse Fourier transforming the data symbol based on the filter, wherein the modulated symbols include the first modulated symbol,
The modulator induces a synchronization sequence for removing intersymbol interference of the first modulation symbol in a time domain in which the preamble is transmitted, and inversely Fourier transforms the derived synchronization sequence based on the filter to convert a second modulation symbol. Generating a second modulation unit, wherein the modulation symbols include the second modulation symbol,
The second modulator may include an interference inducing unit for inducing inter-symbol interference (ISI) of the first modulation symbol overlapping in the time domain in which the preamble is transmitted, and the inter-symbol interference of the first modulation symbol overlapping in the time domain. And a synchronization sequence derivation unit for deriving a synchronization sequence for removing ISI), wherein the second modulation symbol is generated using the derived synchronization sequence. delete delete The method of claim 1,
A resource setting unit which presets a transmission resource for transmitting the data symbol, the synchronization sequence, and the preamble; More,
The transmission resource includes at least one of a frequency characteristic of a subcarrier for transmitting the data symbol and the synchronization sequence and a time domain in which the preamble is transmitted. The method of claim 1,
The data symbol includes at least one of Offset Quadrature Amplitude Modulation (OQAM) data symbol and Quadrature Amplitude Modulation (QAM) data symbol,
The modulator generates the modulation symbols using a filter bank multicarrier (FBMC) scheme based on a filter having the preset frequency response and subcarriers of different frequency bands. The method of claim 1, wherein the first modulator
A mapping unit for mapping the data symbols to subcarriers having different frequency bands; And
A first frequency inverse transform that convolves a data symbol mapped to the subcarrier on a frequency axis with a prototype filter, the filter having the preset frequency response, and inverse Fourier transforms the data symbol convolved with the prototype filter part; More,
And generating the first modulation symbol using the data symbol convolved with the prototype filter and inversely Fourier transformed. delete The method of claim 1, wherein the second modulator
A selection unit for selecting a subcarrier region for transmitting the synchronization sequence; And
Convolving the synchronization sequence mapped to the subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter, which is a filter having a preset frequency response, and inverse Fourier convolves the synchronization sequence convolved with the prototype filter. A second frequency inverse transform unit to convert; More,
The synchronization sequence is derived by using the selected subcarrier region, the time domain in which the preamble is transmitted, and the inter-symbol interference (ISI) overlapping in the time domain, and is convolutional with the prototype filter and inversely Fourier transformed. And generating the second modulation symbol by using the symmetric symbol. The method of claim 1,
The communication unit transmits the first modulation symbol, the second modulation symbol and the preamble by overlapping in the time domain in which the preamble is transmitted.
And a subcarrier for transmitting the synchronization sequence is provided as a set of subcarriers having equal intervals in a frequency domain. delete delete delete delete Generating a first modulation symbol by inverse Fourier transforming a data symbol to be transmitted based on at least one filter having a preset frequency response;
Generating a second modulation symbol by inverse Fourier transforming a synchronization sequence for removing intersymbol interference of the first modulation symbol in a time domain in which a preamble for synchronization of the data symbol is transmitted based on the filter;
Transmitting the generated first modulation symbol, the generated second modulation symbol, and the preamble by overlapping on a time axis; And
Preset transmission resources for transmitting the data symbols, the synchronization sequence, and the preamble,
The transmission resource includes at least one of a frequency characteristic of a subcarrier for transmitting the data symbol and the synchronization sequence and a time domain in which the preamble is transmitted, wherein the first modulation symbol and the second modulation symbol represent the transmission resource. Is generated using
Generating the second modulation symbol includes inducing inter-symbol interference (ISI) of the first modulation symbol that overlaps in the time domain in which the preamble is transmitted, and generating the second modulation symbol that overlaps in the time domain. Deriving a synchronization sequence for canceling inter-symbol interference (ISI), wherein the second modulation symbol is generated using the derived synchronization sequence. delete The method of claim 14,
The data symbol includes at least one of Offset Quadrature Amplitude Modulation (OQAM) data symbol and Quadrature Amplitude Modulation (QAM) data symbol,
Inverse Fourier transform based on at least one filter having a predetermined frequency response is based on a filter bank multicarrier (FBMC) scheme based on a filter having the predetermined frequency response and subcarriers of different frequency bands. Data transmission method comprising a. 15. The method of claim 14, wherein generating the first modulation symbol is
Mapping the data symbols to subcarriers having different frequency bands; And
Convolving a data symbol mapped to the subcarrier on a frequency axis with a prototype filter which is a filter having the preset frequency response, and inverse Fourier transforming the data symbol convolved with the prototype filter; More,
And generating the first modulation symbol using the data symbol convolved with the prototype filter and inversely Fourier transformed. delete 15. The method of claim 14, wherein generating the second modulation symbol is
Selecting a subcarrier region for transmitting the synchronization sequence; And
Convolving the synchronization sequence mapped to the subcarrier for transmitting the synchronization sequence on a frequency axis with a prototype filter, which is a filter having a preset frequency response, and inverse Fourier convolves the synchronization sequence convolved with the prototype filter. Converting; More,
The synchronization sequence is derived using the selected subcarrier region, the time domain in which the preamble is transmitted, and the inter-symbol interference (ISI) overlapping in the time domain, and is convolutional with the prototype filter and inversely Fourier transformed. And generating the second modulation symbol by using a data transmission method. The method of claim 19,
The time domain for transmitting the preamble is selected as a region having a large coefficient size in consideration of an impulse response of the prototype filter.
And the subcarriers for transmitting the synchronization sequence are provided as a set of subcarriers having equal intervals in a frequency domain. delete delete delete

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