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WO2004028105A1 - Systeme de multiplexage par repartition orthogonale de la frequence - Google Patents

Systeme de multiplexage par repartition orthogonale de la frequence Download PDF

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Publication number
WO2004028105A1
WO2004028105A1 PCT/KR2002/002398 KR0202398W WO2004028105A1 WO 2004028105 A1 WO2004028105 A1 WO 2004028105A1 KR 0202398 W KR0202398 W KR 0202398W WO 2004028105 A1 WO2004028105 A1 WO 2004028105A1
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Prior art keywords
block
channel
codes
symbol
estimation
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PCT/KR2002/002398
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English (en)
Inventor
Chang-Bok Joo
Ki-Yeul Han
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Chang-Bok Joo
Ki-Yeul Han
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Publication date
Application filed by Chang-Bok Joo, Ki-Yeul Han filed Critical Chang-Bok Joo
Priority to AU2002359017A priority Critical patent/AU2002359017A1/en
Publication of WO2004028105A1 publication Critical patent/WO2004028105A1/fr

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Classifications

    • 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
    • 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
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
    • 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
    • H04L25/0212—Channel estimation of impulse response
    • H04L25/0214—Channel estimation of impulse response of a single coefficient
    • 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
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • 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
    • H04L27/2651—Modification of fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators for performance improvement
    • 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
    • H04L27/2662—Symbol synchronisation
    • 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
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L2025/0335—Arrangements for removing intersymbol interference characterised by the type of transmission
    • H04L2025/03375—Passband transmission
    • H04L2025/03414—Multicarrier
    • 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
    • H04L25/0204—Channel estimation of multiple channels

Definitions

  • the present invention relates to an orthogonal frequency division multiplexing (OFDM) system; and, more particularly, to an apparatus and a method for estimating a channel and determining a symbol timing for FFT windowing control in an OFDM system which appends channel estimation PN codes as preamble to a signal having a periodic symbol structure of a frame structure such as an OFDM signal, allows real time channel estimation by simplifying a hardware structure for estimating multi-path channel coefficients by using an auto-correlation of the PN codes, determines an accurate symbol timing from the estimated channel coefficients and improve an equalization performance by utilizing values obtained by fast Fourier transforming the estimated channel coefficients as weight coefficient of one- tap equalization.
  • OFDM orthogonal frequency division multiplexing
  • an orthogonal frequency division multiplexing is a communication technique that realizes a fast digital signal transmission against to multi-path by achieving a multi-carrier of data blocks using a fast
  • FFT Fourier transform
  • IFFT inverse fast Fourier transform
  • GI guard interval
  • a channel estimation method capable of accurately knowing a channel coefficient as a delay profile of the channel, must be acquired for channel equalization inducing interferences between symbols.
  • a channel estimation and equalization method in a conventional OFDM system utilizes one-tap equalization method which multiplies symbol sample values of FFT output for the data symbol of the receiving end with a weighted coefficient value which is the symbol sample value of the FFT output in the symbol interval of a preamble is stored at a weighted coefficient storing block by considering an inverse of a value divided by a symbol sample value of the preamble or a sample value of a pilot signal as the weighted coefficient value, on the assumption that inter-symbol interference does not occur since a delay profile of channel is shorter than a guard interval (GI).
  • GI guard interval
  • OFDM orthogonal frequency division multiplexing
  • this present invention provides an apparatus and a method for estimating a channel coefficients and determining symbol timing in an OFDM system with a hardware of a simple structure by allowing an operation of a correlator to be composed of only summation operation.
  • the apparatus and method for estimating a channel and determining symbol timing in an OFDM system are characterized in that: a transmitting end generates N_D -1 numbers of PN code symbol samples, i.e., channel estimation PN codes with a period of N_D -1 at front end of each frame of the OFDM signal at data sample intervals for 3 to 5 periods and the receiving end estimates M number of channel coefficients by a correlation operation between received signal of the preamble period and M number of PN codes circulated by one bit in order which is stored in the memory block ofthe receiving end.
  • the apparatus and method for estimating a channel and determining symbol timing in an OFDM system is characterized in that: a correlator operates only (N_D ⁇ -1)*M times of summation operations since a correlation of PN codes is applied in estimating channel coefficients.
  • the present invention can estimate channel coefficients with a high accuracy in real time for a power line communication with a long delay profile which exceeds a GI of a symbol in the OFDM system. Also, it can determine an accurate symbol timing by determining the first or peak value position of estimated channel coefficients for symbol timing determination. Moreover, it can allow data to be transmitted at a high speed by improving a channel equalization performance using the estimated channel coefficients as a weighted coefficient value of one-tap equalization by fast Fourier transforming the estimated channel coefficients.
  • the present invention is capable of one-tap equalization in frequency domain by allowing a channel characteristics to be exactly known in real time and at a high speed even in the channel environment at which a delay profile exceeds a GI.
  • Fig. 1 is a block diagram showing an OFDM signal frame in accordance with the present invention
  • Fig. 2 depicts the construction of transmitting and receiving ends of the OFDM system utilizing correlation characteristics of PN codes in accordance with the present invention
  • Fig. 3 shows a block diagram of a channel coefficient estimation block and a timing generation block for symbol synchronization shown in Fig. 2;
  • Fig. 4 is a view explaining the correlation operation of a correlator shown in Fig. 3;
  • Fig. 5 represents a channel profile for an estimation example and estimation error.
  • threshold comparison and channel coefficient output block 30 symbol synchronization timing generation block
  • Fig. 1 is a block diagram showing an OFDM signal frame in accordance with the present invention
  • Fig. 2 depicts the construction of transmitting and receiving ends of the OFDM system utilizing correlation characteristics of PN codes in accordance with the present invention
  • Fig. 3 shows a block diagram of a channel coefficient estimation block and a symbol synchronization timing generation block shown in Fig. 2.
  • the OFDM system employs a method that processes a data block in parallel and transmits the data block in parallel in a number of sub-carriers orthogonal to each other.
  • the generation of OFDM signals is obtained by converting a series of data into a parallel data through a serial-to- parallel (S/P) converter 1 at the transmitting end shown in Fig. 2 and processing them at an inverse fast Fourier transform (IFFT) block 3.
  • S/P serial-to- parallel
  • IFFT inverse fast Fourier transform
  • a base band signal from the transmitting end is converted into a digital signal by an analog-to-digital converter (ADC) 11. Thereafter, the data from the transmitting end is recovered by demodulating of a signal demapping (demodulation) block 15 and data decoding of a data decoder 17 after a symbol is recovered by a process of a fast Fourier transformer (FFT) 14.
  • ADC analog-to-digital converter
  • FFT fast Fourier transformer
  • a frame of an OFDM signal in the present invention includes PN code symbols for channel estimation and OFDM data symbols.
  • One symbol of the OFDM signal is composed of N_G ⁇ number of samples of guard intervals and N_D' number of samples of data sample intervals, that is, N_G + N_D ⁇ number of samples.
  • the GI for preventing an inter-symbol interference is created by prefix N_G number of rear end portion samples of the data sample to front end portions of the data samples, and generally the GI is 4-6 times longer than the average delay spread time of the channel and the data sample interval is 4-5 times longer than the GI.
  • the transmitting end includes a PN code generation block 5 for estimating the channel coefficient in time domain and generating channel estimation PN codes at a symbol sample rate(interval) at the front ends of each frame of the OFDM signals.
  • the receiving end includes a channel coefficient estimation block 20 for calculating estimated channel coefficients by a correlation between M number of circulated PN codes at a memory block in the unit of PN code length by receiving the PN codes of the transmitting end, a timing generation block 30 for use in a symbol synchronization for determining a symbol synchronization timing as a position of a periodic peak channel coefficient value appearing by the periodicity of correlation between the PN codes among the estimated channel coefficients calculated from the channel coefficient estimation block 20, a weighted coefficient storing block 18 and one-tap equalizer 19 for utilizing the channel coefficients calculated from the channel coefficient estimation block 20 as weighted coefficient values for one-tap equalization by the FFT.
  • a channel coefficient estimation block 20 for calculating estimated channel coefficients by a correlation between M number of circulated PN codes at a memory block in the unit of PN code length by receiving the PN codes of the transmitting end
  • a timing generation block 30 for use in a symbol synchronization for determining a symbol synchronization timing as a position of
  • channel estimation PN codes having a period of N_D -1 number are generated at a data sample interval by 3 to 5 cycles at front ends of each frame of OFDM signals through the PN code generation block 5 for channel coefficient estimation.
  • the received preamble symbol with PN code is composed of an overlap of transmitted PN codes delayed by M-1 sample time by M number of paths, by a delay profile of the channel. There are received signals being received by a first path, a second path delayed by one sample interval and a third path delayed by two sample intervals. And also, the transmitted PN codes received at each path are received with a magnitude and a phase corresponding to the delay profile.
  • the channel coefficient estimation block 20 since a correlation value between the overlapped PN codes of the receiving end and the non-circulated PN codes ofthe memory block has an auto-correlation with respect to the first path receiving PN code and a cross-correlation with respect to the other delay receiving PN codes, the cross-correlation value becomes 0 by the correlation of the PN code. Therefore, the auto-correlation value corresponding to the first path becomes a first channel coefficient value corresponding to a direct path at the receiving delay profile.
  • the correlation becomes a second channel coefficient value corresponding to the second path at the delay profile by the correlation ofthe PN codes.
  • the correlation becomes a third channel coefficient value corresponding to the third path at the delay profile by the correlation ofthe PN codes.
  • M numbers of channel coefficients are estimated by a correlation between the overlapped PN codes ofthe receiving end and M number of sequentially circulated PN codes ofthe memory block.
  • a correlation between a noise sample additionally received through the channel during the above correlation processes and the circulated PN codes of the memory block becomes a cross-correlation and the cross-correlation value influences on an estimation accuracy ofthe channel coefficient value.
  • the present invention allows channel equalization with respect to the transmission channel exceeding the GI of the symbol causing inter-symbol interferences in an OFDM system.
  • the transmitting end includes a PN code generation block 5 for channel coefficient estimation to generate channel estimation PN codes with a period of NJD'-l numbers at front end of each frame of the OFDM signals at a data sample interval for 3 to 5 cycles.
  • the receiving end includes a channel coefficient estimation block 20 containing M number of circulated PN codes obtained by circulating the transmitted PN code by one bit in order and generates the estimated channel coefficients to input terminals of the timing generation block 30 for use in a symbol synchronization and the FFT block 14.
  • the output of the FFT 14 is stored at the weighted coefficient-storing block 18 for use in one-tap equalizer 19 for the channel equalization for the OFDM data symbols.
  • the channel coefficient estimation block 20 includes a circulated PN codes memory block 21 for storing M number of circulated PN codes obtained by circulating the PN code of the transmitting end by 1 bit in order, a correlator 22 for calculating M number of correlation values by performing a correlation between the PN codes of frame of the transmitted OFDM signal converted at the ADC 11 of the receiving end and the M number of circulated PN codes obtained by circulating the transmitted PN code by 1 bit in order which stored at the circulated PN code memory- block 21, a threshold setting block 23 for setting a threshold level to determine the channel coefficient and a threshold level comparison and channel coefficient output block 24 for finally outputting the estimated channel coefficient values by comparing the M number of estimation channel coefficient calculated at the correlator 22 with the threshold set at the threshold setting block 23.
  • a circulated PN codes memory block 21 for storing M number of circulated PN codes obtained by circulating the PN code of the transmitting end by 1 bit in order
  • a correlator 22 for calculating M number of correlation values by performing
  • the timing generation block 30 for use in a symbol synchronization includes a peak value position extraction block 31 for extracting positions of the periodic peak channel coefficient values appeared by the periodicity of correlation of PN code among the estimated channel coefficients calculated from the channel coefficient estimation block 20, a symbol timing determination block 32 for determining the positions of the peak channel coefficient values extracted from the peak value position extraction block 31 as a symbol synchronization timing and an FFT window control block 33 for outputting to a GI removing block 12 a GI removing control signal to remove the GI in response to the symbol timing determined from the symbol timing determination block 32.
  • the OFDM signals are received through the transmission channel of multi-paths, and the channel estimation PN code symbols placed at the front end of each frame ofthe OFDM signal are received in the overlapped form of M number of different signals attenuated and time-delayed by the delay profile corresponding to the channel characteristics.
  • the received PN code of the receiving end are inputted in order to N_D'-' 1 number of shift registers 41 in the correlator 22 through the ADC block 11 in serial.
  • the correlations between the inputted PN code and M number of PN codes circulated by one bit in order which are stored in M number of shift registers placed in parallel i.e., NJLT- l number of shift registers 42 storing non-circulated PN code, N_D ,; 1 number of shift registers 43 storing PN code circulated by 1 bit...
  • the M number of correlation values are obtained at the same time by summing the binary EX-OR operation at the same bit positions in the shift register, and therefore, these correlation values become M number of estimated channel coefficients.
  • These estimated values are outputted as the determined channel coefficient values by comparison with the tlireshold of the threshold-setting block 23 in the threshold comparison and channel coefficient output block 24.
  • the received preamble PN code ofthe received end is composed of an overlap of transmitted preamble PN code signal through M number of paths delayed by one to M-1 sample intervals which are received through the first path, the second path delayed by one sample time and the third path delayed by two sample time, etc., by the delay profile ofthe channel.
  • the PN codes ofthe transmitting end received from each path are received with a magnitude and a phase corresponding to the delay profile.
  • the channel coefficient estimation block 20 since a correlation value between the overlapped PN code signal ofthe receiving end ofthe shift register 41 and the non-circulated PN code ofthe memory block of the shift register 42 has an auto-correlation with respect to the first path receiving PN code and a cross-correlation with respect to the other delay receiving PN code, the cross-correlation value becomes 0 by the correlation of the PN code. Therefore, the auto-correlation value corresponding to the first path becomes a first channel coefficient value corresponding to a direct path at the receiving delay profile.
  • the correlation becomes a second channel coefficient value corresponding to the second path at the delay profile.
  • the correlation becomes the M ⁇ channel coefficient value corresponding to the M ⁇ path at the delay profile by the correlation ofthe PN codes.
  • M numbers of channel coefficients are estimated at the same time by a parallel processing of correlation between the overlapped PN code signal of the receiving end and M number of sequentially circulated PN codes ofthe memory block 21.
  • a cross-correlation value between a noise sample additionally received through the channel during the above correlation processes and the circulated PN codes of the memory block 21 becomes smaller by spreading operation with the circulated PN codes for thereby increasing the estimation accuracy of the channel coefficient value.
  • the multi-channel coefficient vector is represented by the following Equation (2); m ⁇ ⁇ - ⁇ O Equation (2)
  • the receiving signal vector appending a noise to the multi-path is represented by the following Equation (3);
  • Equation (3) wherein a_0 and a_f represent a coefficient of a direct path without a symbol delay and a coefficient of i-sample time delayed path, respectively.
  • the channel coefficient estimation by taking a correlation between the received signal r (p)' and the s_f ( ⁇ ) code circulated by.i bit in turn, the channel coefficient a_f can be obtained in the range of an error such as
  • Fig. 5 there are shown an example of channel estimation in case that a signal to noise power ratio at the input ofthe receiving end is 13 dB and an estimation error thereof. It is known by the Fig. 5 that the estimation of the channel delay profile is well performed. Since the degree of error is appeared within ⁇ 0.005 (normalizing the largest channel coefficient value to 1 which corresponds to a attenuation below -46 dB in power). Therefore, even if the threshold is set to 0, it is possible that a channel coefficient with a high accuracy of estimation is determined.
  • the present invention extracts the position of the peak value of the estimated channel coefficients outputted from the threshold comparison and channel coefficient output block 24 through the peak value position extraction block 31 in the timing generation block 30 for the purpose of symbol synchronization. And, the present invention outputs to the FFT window controller 33 the decided symbol timing through the symbol timing decision block 32 by determining the count number of position of peak estimated channel coefficient extracted from the peak value position extraction block 31 as a symbol timing which is a start point of the OFDM data symbol following the OFDM preamble PN code in a frame by using the periodicity ofthe output ofthe correlator.
  • the weighted coefficient storing block 18 stores the one-tap equalization weight coefficient values after Fast Fourier Transform (TTF) the estimated channel coefficients outputted from the threshold comparison and channel coefficient output block 24 and then one-tap equalizer 19 performs channel equalization by utilizing the channel coefficients stored in block 18.
  • TTF Fast Fourier Transform
  • the present invention is capable of estimating a transmission channel coefficients accurately in real time in a time domain even for a multi-path transmission channels having a long delay profile which exceeds a guard interval (GI) in an OFDM system and determining symbol timing at the same time, and particularly, simplifying a hardware structure of a symbol synchronization by using a correlation between PN code which accurately extracting channel coefficients at a high speed by configuring an operation of the correlator with only summation operation and determining positions of peak channel coefficient values for a symbol synchronization timing.
  • GI guard interval
  • the present invention is capable of implementing channel equalization to eliminate an inter-symbol interference for a multi-path having a long delay profile which exceeds a GI since weighted tap coefficients of one-tap equalizer is set by the value obtained by FFT the estimated channel coefficients. Since the present invention described above allows channel characteristics to be exactly known in real time even in a power line communication with a long delay spread, it achieves a very excellent and reliable channel equalization and determines a symbol synchronization timing at the same time.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Discrete Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Power Engineering (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

L'invention concerne un appareil et un procédé permettant d'estimer un canal et de déterminer le rythme des symboles afin d'afficher une transformée rapide de Fourier (FFT) dans une fenêtre d'un système de multiplexage par répartition orthogonale de la fréquence (OFDM). Ledit procédé permet d'ajouter des codes PN d'estimation de canal comme préambule à une structure périodique symbolique d'unité de trame; d'estimer rapidement ledit canal par simplification d'une structure matérielle afin d'estimer plusieurs chemins de coefficients de canal à l'aide d'une corrélation de codes PN; de déterminer un rythme de synchronisation de symboles précis à partir des coefficients de canal estimés; et d'améliorer une performance d'égalisation par utilisation de valeurs obtenues à l'aide de la transformée de Fourier rapide qui transforme les coefficients de canal estimés en coefficient de pondération d'égalisation à une prise.
PCT/KR2002/002398 2002-09-18 2002-12-20 Systeme de multiplexage par repartition orthogonale de la frequence WO2004028105A1 (fr)

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Application Number Priority Date Filing Date Title
AU2002359017A AU2002359017A1 (en) 2002-09-18 2002-12-20 An orthogonal frequency division multiplexing system

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KR10-2002-0056746A KR100471538B1 (ko) 2002-09-18 2002-09-18 오에프디엠 시스템의 채널추정과 심볼동기 타이밍결정장치 및 방법
KR10-2002-0056746 2002-09-18

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006075210A3 (fr) * 2005-01-14 2006-09-08 Nokia Corp Systeme et procede d'utilisation de differents intervalles de garde connus dans des systemes de communication a une seule ou plusieurs porteuses
WO2009149422A3 (fr) * 2008-06-06 2010-07-29 Maxim Integrated Products, Inc. Synchroniseur de symbole et de trame à bande étroite robuste pour communication de ligne électrique
US8149967B2 (en) 2008-06-06 2012-04-03 Maxim Integrated Products, Inc. Combined dual feed-forward and feedback analog and digital automatic gain control for broadband communication
US8165172B2 (en) 2008-06-06 2012-04-24 Maxim Integrated Products, Inc. Robust wideband symbol and frame synchronizer for power-line communication
FR2968157A1 (fr) * 2010-11-25 2012-06-01 Korea Electronics Telecomm Dispositif et procédé de transmission de signal de synchronisation
US8276025B2 (en) 2008-06-06 2012-09-25 Maxim Integrated Products, Inc. Block interleaving scheme with configurable size to achieve time and frequency diversity
US8284825B2 (en) 2008-06-06 2012-10-09 Maxim Integrated Products, Inc. Blind channel quality estimator
US8315341B2 (en) 2008-06-06 2012-11-20 Maxim Integrated Products, Inc. Soft repetition code combiner using channel state information
US8315152B2 (en) 2008-06-06 2012-11-20 Maxim Integrated Products, Inc. System and method for applying multi-tone OFDM based communications within a prescribed frequency range
US8320233B2 (en) 2009-06-12 2012-11-27 Maxim Integrated Products, Inc. Transmitter and method for applying multi-tone OFDM based communications within a lower frequency range
US8472576B2 (en) 2008-06-06 2013-06-25 Maxim Integrated Products, Inc. Jammer canceller for power-line communication
CN103546416A (zh) * 2013-07-12 2014-01-29 上海数字电视国家工程研究中心有限公司 Ofdm符号同步方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100585173B1 (ko) 2005-01-26 2006-06-02 삼성전자주식회사 반복적 프리앰블 신호를 갖는 ｏｆｄｍ 신호 수신 방법
KR100770426B1 (ko) * 2006-10-27 2007-10-26 삼성전기주식회사 무선통신 패킷 동기장치 및 그 방법
WO2010061993A1 (fr) * 2008-11-28 2010-06-03 Sas Technologies Co., Ltd. Appareil et procédé d'acquisition de synchronisation de trame
KR101034804B1 (ko) * 2010-03-11 2011-05-16 주식회사 아이닥스 속도제어부를 구비한 도어힌지
KR101553805B1 (ko) 2014-09-15 2015-09-17 아주대학교산학협력단 양방향 릴레이 채널을 위한 아날로그 네트워크 코딩 기반의 랜덤 액세스 방법 및 그 장치

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5371761A (en) * 1992-07-16 1994-12-06 U.S. Philips Corporation Transmission system and receiver for this system
US5848107A (en) * 1995-08-16 1998-12-08 U. S. Philips Corporation Transmission system with improved symbol processing
US6097776A (en) * 1998-02-12 2000-08-01 Cirrus Logic, Inc. Maximum likelihood estimation of symbol offset
US6141393A (en) * 1999-03-03 2000-10-31 Motorola, Inc. Method and device for channel estimation, equalization, and interference suppression
US6304611B1 (en) * 1997-06-19 2001-10-16 Hitachi Denshi Kabushiki Kaisha OFDM modulator and OFDM modulation method for digital modulated wave having guard interval
US6317470B1 (en) * 1998-09-15 2001-11-13 Ibiquity Digital Corporation Adaptive weighting method for orthogonal frequency division multiplexed soft symbols using channel state information estimates
US6442129B1 (en) * 1999-12-06 2002-08-27 Intellon Corporation Enhanced channel estimation

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100197618B1 (ko) * 1996-09-30 1999-06-15 윤종용 Ofdm전송시스템의 채널특성 추정장치
KR100204585B1 (ko) * 1996-12-14 1999-06-15 정선종 오에프디엠/씨디엠에이 방식에 적용될 수 있는 아이에프에프티/에프에프티 블록 및 타이밍 동기방법
US5912876A (en) * 1997-01-15 1999-06-15 Ericsson, Inc. Method and apparatus for channel estimation
KR100228683B1 (ko) * 1997-07-26 1999-11-01 윤종용 Ofdm수신기의 채널추정방법 및 장치
US6795392B1 (en) * 2000-03-27 2004-09-21 At&T Corp. Clustered OFDM with channel estimation
KR100666691B1 (ko) * 2000-12-06 2007-01-11 삼성전자주식회사 오에프디엠 신호의 수신 장치 및 채널 추정을 통한 신호복원 방법

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5371761A (en) * 1992-07-16 1994-12-06 U.S. Philips Corporation Transmission system and receiver for this system
US5848107A (en) * 1995-08-16 1998-12-08 U. S. Philips Corporation Transmission system with improved symbol processing
US6304611B1 (en) * 1997-06-19 2001-10-16 Hitachi Denshi Kabushiki Kaisha OFDM modulator and OFDM modulation method for digital modulated wave having guard interval
US6097776A (en) * 1998-02-12 2000-08-01 Cirrus Logic, Inc. Maximum likelihood estimation of symbol offset
US6317470B1 (en) * 1998-09-15 2001-11-13 Ibiquity Digital Corporation Adaptive weighting method for orthogonal frequency division multiplexed soft symbols using channel state information estimates
US6141393A (en) * 1999-03-03 2000-10-31 Motorola, Inc. Method and device for channel estimation, equalization, and interference suppression
US6442129B1 (en) * 1999-12-06 2002-08-27 Intellon Corporation Enhanced channel estimation

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006075210A3 (fr) * 2005-01-14 2006-09-08 Nokia Corp Systeme et procede d'utilisation de differents intervalles de garde connus dans des systemes de communication a une seule ou plusieurs porteuses
US8315341B2 (en) 2008-06-06 2012-11-20 Maxim Integrated Products, Inc. Soft repetition code combiner using channel state information
US8780691B2 (en) 2008-06-06 2014-07-15 Maxim Integrated Products, Inc. System and method for applying multi-tone OFDM based communications within a prescribed frequency range
US8149967B2 (en) 2008-06-06 2012-04-03 Maxim Integrated Products, Inc. Combined dual feed-forward and feedback analog and digital automatic gain control for broadband communication
US8165172B2 (en) 2008-06-06 2012-04-24 Maxim Integrated Products, Inc. Robust wideband symbol and frame synchronizer for power-line communication
US9054786B2 (en) 2008-06-06 2015-06-09 Maxim Integrated Products, Inc. System and method for applying multi-tone OFDM based communications within a prescribed frequency range
US8276025B2 (en) 2008-06-06 2012-09-25 Maxim Integrated Products, Inc. Block interleaving scheme with configurable size to achieve time and frequency diversity
US8284825B2 (en) 2008-06-06 2012-10-09 Maxim Integrated Products, Inc. Blind channel quality estimator
WO2009149422A3 (fr) * 2008-06-06 2010-07-29 Maxim Integrated Products, Inc. Synchroniseur de symbole et de trame à bande étroite robuste pour communication de ligne électrique
US8139614B2 (en) 2008-06-06 2012-03-20 Maxim Integrated Products, Inc. Robust narrowband symbol and frame synchronizer for power-line communication
US8848836B2 (en) 2008-06-06 2014-09-30 Maxim Integrated Products, Inc. Jammer canceller for power-line communication
US8315152B2 (en) 2008-06-06 2012-11-20 Maxim Integrated Products, Inc. System and method for applying multi-tone OFDM based communications within a prescribed frequency range
US8582668B2 (en) 2008-06-06 2013-11-12 Maxim Integrated Products, Inc. Soft repetition code combiner using channel state information
US8472576B2 (en) 2008-06-06 2013-06-25 Maxim Integrated Products, Inc. Jammer canceller for power-line communication
US8320233B2 (en) 2009-06-12 2012-11-27 Maxim Integrated Products, Inc. Transmitter and method for applying multi-tone OFDM based communications within a lower frequency range
US8879379B1 (en) 2009-06-12 2014-11-04 Maxim Integrated Products, Inc. Transmitter and method for applying multi-tone OFDM based communications within a lower frequency range
FR2968157A1 (fr) * 2010-11-25 2012-06-01 Korea Electronics Telecomm Dispositif et procédé de transmission de signal de synchronisation
CN103546416A (zh) * 2013-07-12 2014-01-29 上海数字电视国家工程研究中心有限公司 Ofdm符号同步方法

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