KR19980023760A - Channel Characteristics Estimator for OFDM Transmission System - Google Patents

Channel Characteristics Estimator for OFDM Transmission System Download PDF

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KR19980023760A
KR19980023760A KR1019960043260A KR19960043260A KR19980023760A KR 19980023760 A KR19980023760 A KR 19980023760A KR 1019960043260 A KR1019960043260 A KR 1019960043260A KR 19960043260 A KR19960043260 A KR 19960043260A KR 19980023760 A KR19980023760 A KR 19980023760A
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channel
subchannels
signal
channel estimation
estimation signal
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KR1019960043260A
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KR100197618B1 (en
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민병민
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김광호
삼성전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
    • H04L25/023—Channel estimation using sounding signals with direct estimation from sounding signals with extension to other symbols
    • H04L25/0232—Channel estimation using sounding signals with direct estimation from sounding signals with extension to other symbols by interpolation between sounding signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
    • H04L1/0084—Formats for payload data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2626—Arrangements specific to the transmitter only
    • H04L27/2627—Modulators
    • H04L27/2628—Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2649—Demodulators
    • H04L27/265—Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • Discrete Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Power Engineering (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

본 발명은 OFDM전송시스템의 채널특성 추정장치에 관한 것으로서, 전송할 데이타에 에러정정부호를 부가하고 역고속푸리에변환하는 전송데이타처리부와, 상기 부채널들의 주파수특성에 근거하여 채널추정신호를 발생하는 채널추정신호발생부와, 상기 전송데이타 및 채널추정신호를 입력받아 아날로그변환하여 수신측으로 전송하는 데이타전송부와, 상기 데이타전송부를 통해 전송되는 신호를 수신받아 디지탈변환하며, 디지탈변환된 신호를 등화한 후 고속푸리에변환하는 수신데이타처리부, 및 상기 수신데이타처리부로부터 출력되는 신호를 입력받아 이중 상기 채널추정신호에 근거하여 상기 부채널들 각각의 특성을 추정하는 채널특성추정부를 포함한다. 이와 같은 본 발명은 OFDM전송시스템의 송신기에서 채널특성 추정결과에 근거하여 각 채널의 특성에 맞게 전송데이타를 보낼 수 있으므로 각 채널에서의 전송효율을 극대화할 수 있는 효과를 가져온다.The present invention relates to an apparatus for estimating channel characteristics of an OFDM transmission system, comprising: a transmission data processor for adding an error correcting code to data to be transmitted and performing inverse fast Fourier transform; and a channel for generating a channel estimation signal based on frequency characteristics of the subchannels. An estimation signal generation unit, a data transmission unit for receiving the transmission data and the channel estimation signal and converting the analog signal to a receiving side, and receiving the signal transmitted through the data transmission unit, performing digital conversion, and equalizing the digitally converted signal. And a channel characteristic estimator for receiving a signal output from the received data processor and estimating characteristics of each of the subchannels based on the channel estimation signal. As described above, according to the present invention, the transmitter of the OFDM transmission system can transmit the transmission data according to the characteristics of each channel based on the channel characteristic estimation result, thereby maximizing the transmission efficiency in each channel.

Description

OFDM전송시스템의 채널특성 추정장치Channel Characteristics Estimator for OFDM Transmission System

본 발명은 OFDM전송시스템에 관한 것으로서, 보다 상세하게는, 부채널들의 특성을 추정하기 위한 OFDM전송시스템의 채널특성 추정장치에 관한 것이다.The present invention relates to an OFDM transmission system, and more particularly, to an apparatus for estimating channel characteristics of an OFDM transmission system for estimating characteristics of subchannels.

현재 지상방송에서는 QAM과 VSB의 다치화가 이미 한계에 와 있기 때문에 여기서 전송속도는 거의 결정되며, 같은 다치수라도 심볼 전송속도를 올리면 그 대역폭의 전송속도는 향상된다. 그렇다고, 심볼 전송속도를 현재 이상으로 끌어 올리면 다중경로의 간섭에 의하여 전파가 방해를 받게 되며, 특히 고층빌딩이 난립하는 지역에서는 이러한 문제가 더욱 심각해 진다. 이와 같은 문제를 해결하기 위하여, 유럽등지에서는 대역폭당의 전송속도의 향상과 간섭방지의 이중효과를 노린 디지탈 변조방식의 OFDM개발에 전력하고 있다.In the current terrestrial broadcasting, since the multiplication of QAM and VSB is already limited, the transmission rate is almost determined here, and even if the same multiple value is raised, the transmission speed of the bandwidth is improved. However, if the symbol transmission speed is raised above the present, the radio wave is disturbed by the multipath interference, and this problem becomes more serious in the area where high-rise buildings are in trouble. In order to solve such a problem, in Europe, etc., the development of digital modulation scheme OFDM aimed at the dual effect of improving the transmission rate per bandwidth and preventing interference.

대부분의 디지탈 변조방식이 단일반송파를 사용하는데 반하여, OFDM은 수백의 부반송파(sub carrier)를 사용하는 변조방식으로 그 이름에서 알 수 있는 바와 같이, 인접하는 각 반송파는 직교한다. 따라서, 각 반송파의 주파수성분은 중복되어도 상관 없으며 통상의 주파수 분할 다중화(FDM)에 비해 주파수의 이용효율이 높다.While most digital modulation schemes use a single carrier, OFDM is a modulation scheme that uses hundreds of subcarriers. As its name suggests, each adjacent carrier is orthogonal. Therefore, the frequency components of each carrier may be overlapped and the frequency utilization efficiency is higher than that of the conventional frequency division multiplexing (FDM).

이와 같은 시스템에서 사용가능한 부채널들의 특성만 알 수 있다면, 각 채널의 용량에 맞게 송신측에서 데이타를 전송할 수 있으므로 전송효율을 더욱 높일 수 있게 된다. 따라서, 전송효율을 극대화하기 위하여 채널의 특성을 추정할 수 있는 장치가 요구되어 졌다.If only the characteristics of the sub-channels available in such a system can be known, the transmission side can transmit data according to the capacity of each channel, thereby further increasing the transmission efficiency. Therefore, in order to maximize transmission efficiency, an apparatus capable of estimating channel characteristics has been required.

도 1a는 본 발명에 따른 OFDM전송시스템의 송신기, 도 1b는 수신기를 나타낸 구성도,1A is a block diagram illustrating a transmitter of an OFDM transmission system according to the present invention, and FIG. 1B is a receiver.

도 2는 도 1a의 채널추정신호발생부(13)를 나타낸 상세구성도,FIG. 2 is a detailed configuration diagram illustrating the channel estimation signal generator 13 of FIG. 1A;

도 3은 도 1b의 채널특성추정부(26)를 나타낸 상세구성도,3 is a detailed block diagram showing the channel characteristic estimation unit 26 of FIG.

도 4는 OFDM전송시스템의 채널특성을 나타낸 도면.4 is a diagram illustrating channel characteristics of an OFDM transmission system.

※ 도면의 주요부분에 대한 부호의 설명※ Explanation of code for main part of drawing

13 : 채널추정신호발생부26 : 채널특성추정부13 channel estimation signal generation unit 26 channel characteristic estimation

261 : 보간부262 : SNR계산부261: interpolation unit 262: SNR calculation unit

263 : 채널테이블263: Channel Table

본 발명에 의한 OFDM전송시스템의 채널특성 추정장치는, OFDM전송시스템의 부채널들의 특성을 추정하기 위한 장치에 있어서, 전송할 데이타에 에러정정부호를 부가하고 역고속푸리에변환하는 전송데이타처리부, 상기 부채널들의 주파수특성에 근거하여 채널추정신호를 발생하는 채널추정신호발생부, 상기 전송데이타 및 채널추정신호를 입력받아 아날로그변환하여 수신측으로 전송하는 데이타전송부, 상기 데이타전송부를 통해 전송되는 신호를 수신받아 디지탈변환하며, 디지탈변환된 신호를 등화한 후 고속푸리에변환하는 수신데이타처리부, 및 상기 수신데이타처리부로부터 출력되는 신호를 입력받아 이중 상기 채널추정신호에 근거하여 상기 부채널들 각각의 특성을 추정하는 채널특성추정부를 포함한다.An apparatus for estimating channel characteristics of an OFDM transmission system according to the present invention is a device for estimating characteristics of subchannels of an OFDM transmission system. A channel estimation signal generator for generating a channel estimation signal based on the frequency characteristics of the channels, a data transmission unit for receiving the transmission data and the channel estimation signal and converting the analog signal to a receiver, and receiving the signal transmitted through the data transmission unit Receiving and processing a digital signal, equalizing the digitally converted signal, and then receiving a fast Fourier transform and a signal output from the receiving data processor, and estimating characteristics of each of the subchannels based on the channel estimation signal. Channel characteristic estimation.

이하, 첨부한 도면들을 참조하여 본 발명의 바람직한 실시예를 상세히 설명하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

도 1은 본 발명에 의한 OFDM전송시스템을 나타낸 것으로, 도 1a는 송신기를, 도 1b는 수신기를 나타낸다.Figure 1 shows an OFDM transmission system according to the present invention, Figure 1a shows a transmitter, Figure 1b shows a receiver.

먼저, 도 1a의 송신기는 송신데이타의 에러를 방지하기 위하여 에러정정부호를 부가하는 에러정정부호부가부(11)와, 에러정정부호가 부가된 신호를 입력받아 역고속푸리에변환(Inverse Fast Fourier Transform)을 수행하는 역고속푸리에변환부(IFFT)(12)를 구비한다. 도 1a의 송신기는 또한, 채널추정신호를 발생하는 채널추정신호발생부(13)를 구비한다. 역고속푸리에변환부(12)와 채널추정신호발생부(13)의 신호출력단에는 입력신호를 디지탈-아날로그변환하는 D/A변환부(14)가 연결되며, D/A변환부(14)의 출력단은 전송신호를 출력하기 위한 인터페이스부(15)에 연결된다.First, the transmitter of FIG. 1A receives an error correcting code adder 11 that adds an error correcting code to prevent an error of transmission data, and an inverse fast Fourier transform. Inverse Fast Fourier Transform (IFFT) 12 is provided. The transmitter of FIG. 1A also includes a channel estimation signal generator 13 for generating a channel estimation signal. A signal output terminal of the inverse fast Fourier transform unit 12 and the channel estimation signal generator 13 is connected to a D / A converting unit 14 for digital-to-analog converting an input signal. The output terminal is connected to the interface unit 15 for outputting the transmission signal.

한편, 도 1b의 수신기는 도 1a의 송신기로부터 전송되는 신호를 수신받는 인터페이스부(21)와, 수신받은 신호를 아날로그-디지탈변환하는 A/D변환부(22)를 구비한다. A/D변환부(22)의 신호출력단에는 입력되는 신호를 등화하는 등화부(23)가 연결되며, 등화부(23)에는 등화된 신호를 고속푸리에변환하는 고속푸리에변환부(FFT)(25)가 연결된다. 고속푸리에변환부(25)에는 송신기에서 보낸 채널추정신호에 근거하여 각 부채널들의 특성을 추정하는 채널특성추정부(26)와, 입력되는 신호의 에러를 정정하는 에러정정부(27)가 연결된다. 그리고, A/D변환부(22)에는 신호의 동기를 검출하는 동기검출부(24)가 연결되며, 동기검출부(24)로부터 검출된 동기는 고속푸리에변환부(25) 및 에러정정부(27)로 공급된다.Meanwhile, the receiver of FIG. 1B includes an interface unit 21 that receives a signal transmitted from the transmitter of FIG. 1A, and an A / D converter 22 that performs analog-digital conversion of the received signal. A signal output terminal of the A / D converter 22 is connected to an equalizer 23 for equalizing an input signal, and the equalizer 23 is a fast Fourier transform unit (FFT) 25 for fast Fourier transforming the equalized signal. ) Is connected. The fast Fourier transform unit 25 is connected to a channel characteristic estimator 26 for estimating characteristics of each subchannel based on a channel estimation signal sent from a transmitter, and an error correction unit 27 for correcting an error of an input signal. do. The A / D converter 22 is connected to a synchronization detector 24 for detecting signal synchronization, and the synchronization detected from the synchronization detector 24 is performed by the fast Fourier transform unit 25 and the error correction unit 27. Is supplied.

이와 같이 구성된 본 발명의 동작을 도 2 내지 도 4를 참조하여 좀 더 상세히 설명하면 다음과 같다.The operation of the present invention configured as described above will be described in more detail with reference to FIGS. 2 to 4.

먼저, 도 1a의 에러정정부호부가부(11)는 전송데이타에 에러정정부호를 부가하며, 에러정정부호가 부가된 신호를 역고속푸리에변환부(12)로 출력한다. 역고속푸리에변환부(12)는 입력되는 신호를 역고속푸리에변환하며, 그 결과로 주파수영역의 신호가 시간영역의 신호로 변환된다.First, the error correcting code adding unit 11 of FIG. 1A adds an error correcting code to the transmission data, and outputs a signal to which the error correcting code is added to the inverse fast Fourier transform unit 12. The inverse fast Fourier transform unit 12 converts an input signal into an inverse fast Fourier transform, and as a result, a signal in the frequency domain is converted into a signal in the time domain.

한편, 채널추정신호발생부(13)는 전송채널의 특성을 추정하기 위한 추정신호를 발생한다.Meanwhile, the channel estimation signal generator 13 generates an estimation signal for estimating the characteristics of the transmission channel.

도 2는 채널추정신호발생부(13)를 나타낸 상세구성도이며, 도 4는 전송채널의 주파수특성을 나타내는 그래프이다. 도 4에서, fM은 사용가능한 주파수대역에서의 최대주파수를 나타내며, 여기서 M은 사용가능한 부채널들의 갯수를 나타낸다. 채널추정신호발생부(13)는 도 2에 나타낸 바와 같이, 각 채널의 주파수특성값을 갖는 사인파형들(sinusoidal waveform)을 가산하는 가산기(131)로 구성된다. 즉, 가산기(131)는 입력되는 사인파형들을 가산하며, 가산결과를 채널추정신호로 발생한다. 이때, 입력파형의 갯수 N은 M보다 작은 값으로 설정한다. OFDM에서는 한개 부채널의 주파수대역이 매우 작기 때문에 모든 부채널에 대해서 채널추정신호를 보내는 것이 가장 이상적이지만 실제 시스템에서는 인접채널간의 간섭(ISI)등으로 인하여 모든 부채널에 채널추정신호를 보낼 수 없다. 또한, 모든 부채널에 채널추정신호를 전송하게 되면 송신기의 복잡도만 증가하게 된다. 따라서, 송신기는 N개의 부채널에 대해서만 채널추정신호를 발생하다. 가산기(131)에 입력되는 사인파형들은 그 위상(φ)을 가변하므로써, 가산결과로 발생되는 채널추정신호를 또한 가변시킬 수 있다.FIG. 2 is a detailed block diagram showing the channel estimation signal generator 13, and FIG. 4 is a graph showing the frequency characteristics of the transmission channel. In Figure 4, f M represents the maximum frequency in the usable frequency band, where M represents the number of available sub-channels. As shown in FIG. 2, the channel estimation signal generation unit 13 includes an adder 131 for adding sinusoidal waveforms having frequency characteristic values of each channel. That is, the adder 131 adds input sinusoids, and generates an addition result as a channel estimation signal. At this time, the number of input waveforms N is set to a value smaller than M. In OFDM, since the frequency band of one subchannel is very small, it is ideal to send channel estimation signals for all subchannels, but in real systems, channel estimation signals cannot be sent to all subchannels due to interference between adjacent channels (ISI). . In addition, when the channel estimation signal is transmitted to all subchannels, only the complexity of the transmitter increases. Therefore, the transmitter generates a channel estimation signal only for the N subchannels. The sinusoidal waveforms input to the adder 131 can also vary the channel estimation signal generated as a result of the addition by varying the phase phi.

D/A변환부(14)는 역고속푸리에변환부(12) 및 채널추정신호발생부(13)로부터 출력되는 신호들을 아날로그로 변환시켜 출력한다. 인터페이스부(15)는 입력되는 신호를 수신기로 전송한다.The D / A converter 14 converts the signals output from the inverse fast Fourier transform unit 12 and the channel estimation signal generator 13 into analog and outputs them. The interface unit 15 transmits an input signal to the receiver.

한편, 도 1b 수신기의 인터페이스부(21)는 송신기로부터 전송되는 신호를 수신받는다. A/D변환부(22)는 수신받는 신호를 아날로그-디지탈변환한다. 등화부(23)는 디지탈변환된 신호를 입력받으며, 입력되는 신호를 등화한다. 고속푸리에변환부(25)는 등화된 신호를 입력받아 고속푸리에변환하며, 그 결과로 시간영역의 신호가 주파수영역의 신호로 변환된다. 한편, 동기검출부(24)는 디지탈변환된 신호로부터 동기를 검출하며, 검출한 동기를 고속푸리에변환부(25)로 공급한다.Meanwhile, the interface unit 21 of the receiver of FIG. 1B receives a signal transmitted from a transmitter. The A / D conversion unit 22 analog-digital converts the received signal. The equalizer 23 receives the digitally converted signal and equalizes the input signal. The fast Fourier transform unit 25 receives the equalized signal and performs the fast Fourier transform. As a result, the signal in the time domain is converted into the signal in the frequency domain. On the other hand, the synchronization detecting unit 24 detects synchronization from the digitally converted signal, and supplies the detected synchronization to the fast Fourier transform unit 25.

채널특성추정부(26)는 송신기에서 보낸 채널추정신호를 이용하여 전송채널들의 특성을 추정한다.The channel characteristic estimator 26 estimates the characteristics of the transmission channels using the channel estimation signal sent from the transmitter.

도 3은 채널특성추정부(26)를 나타낸 상세구성도이다. 채널특성추정부(26)는 보간부(261)와, SNR계산부(262), 및 채널테이블(263)로 구성된다.3 is a detailed block diagram showing the channel characteristic estimation unit 26. As shown in FIG. The channel characteristic estimator 26 is composed of an interpolator 261, an SNR calculator 262, and a channel table 263.

도 3의 채널특성추정부(26)에서 보간부(261)는 송신기로부터 전송된 N개의 채널추정신호를 M개로 보간하며, 보간결과인 M개 채널의 주파수특성을 출력한다. 이때, 보간부(261)는 선형보간(Linear interpolation) 또는 반복보간(Repetiton interpolation)등의 방법을 이용할 수 있다. SNR계산부(262)는 M개 채널의 주파수특성을 입력받아 각 채널에서의 신호대잡음비(Signal-to-Noise Ratio; 이하, 0gSNR0h이라 함)를 계산한다. SNR계산부(262)는 M개의 부채널들에 대하여 개별적으로 SNR을 계산하며, 계산결과들을 채널테이블(263)에 기록한다. 이와 같이, 채널테이블(263)에는 부채널들의 채널특성이 기록된다.In the channel characteristic estimator 26 of FIG. 3, the interpolator 261 interpolates N channel estimation signals transmitted from a transmitter to M, and outputs frequency characteristics of M channels, which are the interpolation results. In this case, the interpolation unit 261 may use a method such as linear interpolation or repetition interpolation. The SNR calculator 262 receives frequency characteristics of M channels and calculates a signal-to-noise ratio (hereinafter, referred to as 0gSNR0h) in each channel. The SNR calculator 262 calculates SNRs individually for the M subchannels, and records the calculation results in the channel table 263. In this way, the channel characteristics of the subchannels are recorded in the channel table 263.

이와 같이 채널테이블에 기록된 내용을 이용하여, 송신기에서는 각 채널특성에 맞게 전송데이타를 보낼 수 있으므로 각 채널에서의 전송효율을 극대화할 수 있는 효과를 가져온다.By using the contents recorded in the channel table as described above, the transmitter can transmit the transmission data according to the characteristics of each channel, thereby maximizing the transmission efficiency in each channel.

본 발명의 목적은, 직교 주파수 분할 다중화(Orthogonal Frequency Division Multiplexing; 이하, 0gOFDM0h이라 함)변조방식의 전송시스템에서 사용가능한 부채널들의 특성을 추정하여 각 채널에서의 전송효율을 극대화시킬 수 있도록 한 OFDM전송시스템의 채널특성 추정장치를 제공함에 있다.An object of the present invention is to estimate the characteristics of subchannels that can be used in an orthogonal frequency division multiplexing (hereinafter, referred to as 0gOFDM0h) modulation system to maximize transmission efficiency in each channel. An apparatus for estimating channel characteristics of a transmission system is provided.

Claims (4)

OFDM전송시스템의 부채널들의 특성을 추정하기 위한 장치에 있어서,An apparatus for estimating characteristics of subchannels in an OFDM transmission system, 전송할 데이타에 에러정정부호를 부가하고 역고속푸리에변환하는 전송데이타처리부;A transmission data processor for adding an error correcting code to the data to be transmitted and performing inverse fast Fourier transform; 상기 부채널들의 주파수특성에 근거하여 채널추정신호를 발생하는 채널추정신호발생부;A channel estimation signal generator for generating a channel estimation signal based on the frequency characteristics of the subchannels; 상기 전송데이타 및 채널추정신호를 입력받아 아날로그변환하여 수신측으로 전송하는 데이타전송부;A data transmitter for receiving the transmission data and the channel estimation signal and converting the analog data to a receiver; 상기 데이타전송부를 통해 전송되는 신호를 수신받아 디지탈변환하며, 디지탈변환된 신호를 등화한 후 고속푸리에변환하는 수신데이타처리부; 및A reception data processing unit for receiving a signal transmitted through the data transmission unit, performing digital conversion, equalizing the digitally converted signal, and then performing fast Fourier transform; And 상기 수신데이타처리부로부터 출력되는 신호를 입력받아 이중 상기 채널추정신호에 근거하여 상기 부채널들 각각의 특성을 추정하는 채널특성추정부를 포함하는 OFDM전송시스템의 채널특성 추정장치.And a channel characteristic estimator which receives a signal output from the reception data processor and estimates characteristics of each of the subchannels based on the channel estimation signal. 제 1항에 있어서, 상기 채널추정신호발생부는 상기 부채널의 주파수특성을 나타내는 사인파형들을 가산하는 가산기로 구성되는 것을 특징으로 하는 OFDM전송시스템의 채널특성 추정장치.2. The apparatus of claim 1, wherein the channel estimation signal generator comprises an adder for adding sinusoids representing frequency characteristics of the subchannels. 제 2항에 있어서, 상기 채널추정신호발생부는 상기 부채널들 중 소정의 채널들에 대한 주파수특성만을 이용하여 상기 채널추정신호를 발생하는 것을 특징으로 하는 OFDM전송시스템의 채널특성 추정장치.3. The apparatus of claim 2, wherein the channel estimation signal generator generates the channel estimation signal using only frequency characteristics of predetermined channels among the subchannels. 제 1항 또는 제 3항에 있어서, 상기 채널특성추정부는The method of claim 1 or 3, wherein the channel characteristic estimation 상기 소정 채널들의 주파수특성에 의하여 발생된 채널추정신호를 입력받아 전체 부채널의 갯수로 보간하여 상기 부채널들 각각에 대한 주파수특성을 출력하는 보간부; 상기 부채널들 각각의 주파수특성을 입력받아 개별적으로 신호대잡음비(SNR)를 계산하는 SNR계산부; 및 상기 부채널들 각각에 대하여 계산된 SNR을 저장하는 채널테이블로 구성되는 것을 특징으로 하는 OFDM전송시스템의 채널특성 추정장치.An interpolation unit which receives a channel estimation signal generated by the frequency characteristics of the predetermined channels and outputs frequency characteristics for each of the subchannels by interpolating the total number of subchannels; An SNR calculator configured to receive frequency characteristics of each of the subchannels and separately calculate a signal-to-noise ratio (SNR); And a channel table for storing the SNR calculated for each of the subchannels.
KR1019960043260A 1996-09-30 1996-09-30 Channel characteristic tracking device of ofdm transmitting system KR100197618B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030014078A (en) * 2001-08-10 2003-02-15 최승국 OFDM wireless transmission system using MMSE channel estimation
KR100471538B1 (en) * 2002-09-18 2005-02-21 한기열 Channel estimation and symbol timing decision apparatus and method of ofdm system
KR100921685B1 (en) * 2007-11-28 2009-10-15 전자부품연구원 Method and Apparatus for channel estimation of high speed wide band wireless modem

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030014078A (en) * 2001-08-10 2003-02-15 최승국 OFDM wireless transmission system using MMSE channel estimation
KR100471538B1 (en) * 2002-09-18 2005-02-21 한기열 Channel estimation and symbol timing decision apparatus and method of ofdm system
KR100921685B1 (en) * 2007-11-28 2009-10-15 전자부품연구원 Method and Apparatus for channel estimation of high speed wide band wireless modem

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