Samsung Electronics Co., Ltd.

Yonsei University

Yung-soo Kim

Sung-jin Kim

Jong-Hyeuk Lee

Ho-Jin Kim

Ki-ho Kim

Yong-Suk Lee

Seong-jin Kim

Dae-Sik Hong

Ji-hoon Park

Jin-sook Kim

Hyeon-woo Lee

Chan-soo Hwang

Hwa-sun Yoo

Myong-hee Park

Byung-jang Jeong

Ji-yong Jun

Provided are a method and apparatus for compensating for a frequency offset in an interleaved frequency division multiple access. The method compensates for a frequency offset between a transmission signal and a reception signal for a uuser (1&#x2266;u&#x2266;U, where U denotes the number of users) in an interleaved frequency division multiple access. The method includes: (a) estimating the frequency offset from a selection signal that is determined as the reception signal for the uuser in an initial mode and as a feedback signal in a normal mode; (b) estimating multiple access interferences representing an extent to which reception signals for iother users (1&#x2266;i&#x2266;U&#x2212;1) at the same time interfere with the reception signal for the uuser; (c) subtracting the estimated multiple access interferences from the reception signal for the uuser and determining the subtraction result as the feedback signal; (d) determining whether steps (a), (b), and (c) have been repeated a predetermined number of times, and if it is determined that steps (a), (b), and (c) have not been repeated the predetermined number of times, going back to step (a); and (e) if it is determined that steps (a), (b), and (c) have been repeated the predetermined number of times, estimating the transmission signal for the uuser using the feedback signal finally determined in step (c) and the estimated frequency offset.

Method and apparatus for compensating for the frequency offset in interleaved frequency division multiple access

An apparatus and method for generating an edge sidelobe canceling signal and an uplink communication apparatus using the same in an orthogonal frequency division multiplexing access (OFDMA) system. The uplink communication apparatus includes a transmitting terminal. The transmitting terminal includes a signal mapping unit, a serial-to-parallel conversion unit, an edge sidelobe canceling signal generation unit, an inverse fast Fourier transform (IFFT) unit, and a guard interval insertion and parallel-to-serial conversion unit. The edge sidelobe canceling signal generation unit generates an upper edge sidelobe canceling signal corresponding to an inner product of a transmission signal vector of the transmitting terminal and an optimized upper weight vector and a lower edge sidelobe canceling signal corresponding to an inner product of the transmission signal vector of the transmitting terminal and an optimized lower weight vector and allocates the upper and lower edge sidelobe canceling signals to subcarriers in guard intervals, respectively.

Method and apparatus for generating an edge sidelobe canceling signal and uplink communication method and apparatus using the same in an OFDMA system

A mobile communication apparatus having an antenna array and a mobile communication method performed in the mobile communication apparatus, wherein the mobile communication apparatus includes a base station and mobile station, each having an antenna array. The mobile station measures the downlink characteristics of a channel for each antenna from a signal received from a base station, determines long-term information in which the correlation property of the channel for each antenna has been reflected from the measured downlink characteristics, transforms the long-term information into a feedback signal, and transmits the feedback signal to the base station. The base station receives the feedback signal, restores the long-term information from the received feedback signal, performs basis mapping and basis transformation on a dedicated physical channel signal using the restored long-term information, adds the basis-mapped and basis-transformed signal to each of pilot channel signals, and transmits the addition results to the mobile station.

Mobile communication apparatus including an antenna array and mobile communication method

A data communication apparatus and method based on orthogonal frequency division multiple access (OFDMA) are provided. In the data communication apparatus, a (U+1)-th encoder in a u-th user transmitting unit among U user transmitting units which transmit corresponding user information to a base station part encodes the user information and outputting the result of encoding as Nu-th user symbols. A user signal generator generates a u-th user signal xin a temporal domain from the u-th user symbol Areceived from the (U+1)-th encoder according to a formula, x=aexp(j2&#x3c0;kn/N). A second cyclic extension symbol inserter inserts a cyclic extension symbol into the u-th user signal. A second signal transmitter converts the result of insertion into a symbol block signal and transmitting the symbol block signal to the base station part. Here, 1&#x2266;N&#x3c;N. Accordingly, the hardware of a user part can be optionally simplified very much. Communication efficiency can be increased in a given channel environment. In addition, different types of user parties having different complexities can communicate with a base station part using a single data format.

Data communication apparatus and method based on orthogonal frequency division multiple access

A mobile communication apparatus having multiple transmission antennas and multiple reception antennas and a mobile communication method used in the mobile communication apparatus, wherein a base station, which has at least one reception antenna, restores long-term and short-term information determined in consideration of first characteristics in a mobile station, which has at least one transmission antenna, from a feedback signal received from the mobile station, spatially processes dedicated physical channel signals using basis information produced from the restored long-term and short-term information, and transmits the results of addition of the spatially-processed signals to pilot signals to the mobile station, wherein the first characteristics are the characteristics of the downlink channels of the respective transmission and reception antennas. Accordingly, the feedback of long-term and short-term information from the mobile station to the base station minimizes the effects of fading, interference, and noise and maximizing throughput.

Mobile communication apparatus including transceiving multi-antennas and mobile communication method

A method for transmitting orthogonal frequency division multiplexing (OFDM) signals including coding the OFDM signals; forming a block of N coded data and dividing the block into L M-sized small blocks; M-point inverse fast Fourier transforming the L small blocks; combining the transformed blocks to generate an N-sized inversely-transformed block; attaching a cyclic prefix to the N-sized block; and transforming the blocks into an analog signal; and transmitting the analog signal. A method of receiving OFDM signals including digitally converting received OFDM signals and obtaining a samples from the transformed signals; detecting the starting point of an N-sized signal sample block from the samples; dividing the signal sample block into L M-sized small blocks M-point fast Fourier transforming the L small blocks; combining the transformed small blocks to generate an N-sized transform block; detecting data from the generated block, and decoding the detected data. N, M and L are integers of 1 or more and L=N/M.

Method for transmitting and receiving orthogonal frequency division multiplexing signal and apparatus therefor

A method and apparatus for synchronizing an OFDM receiver is provided. The method includes the steps of: (a) receiving an OFDM reference symbol before user data OFDM symbols, the OFDM reference symbol having sub-symbol signals at only random, even-numbered sub-carriers and having no signals at any other even-numbered sub-carriers and all odd-numbered sub-carriers in the frequency domain, and the first half of the symbol having the same characteristics as the remaining half in the time domain; (b) obtaining OFDM digital signal samples r by sampling the received OFDM reference symbol and converting the OFDM reference symbol samples into digital signals; (c) obtaining a predetermined timing metric for each of the OFDM signal samples r according to the time-domain characteristics of the reference symbol, and detecting the point in time at which the power of the timing metric is maximum as the starting point of a symbol/frame of the OFDM signal; and (d) correcting for the offsets of sub-carrier frequencies that are less than is the frequency spacing between two adjacent sub-carriers by obtaining a frequency offset from the phase of the timing metric at the detected symbol/frame starting point, and correcting for the offsets of sub-carrier frequencies that are greater than the frequency spacing between two adjacent sub-carriers by obtaining the value which maximizes the power metrics according to the frequency-domain characteristics of the reference symbol.

Method and apparatus for synchronizing orthogonal frequency division multiplexing (OFDM) receiver

A non-linear signal receiver. The non-linear signal receiver for detecting an original data a from an input signal r(t) which is a binary data stream input through a channel or reproduced from data recorded on a storing device includes: an analog-to-digital converter (ADC) for sampling the input value according to sampling timing phases, and converting the sampled data into a digital signal r ; a modeling portion including 2N&plus;1 taps P (n&equals;&minus;N, . . . , 0, . . . , N) each for selecting one of 2 tap values according to each pattern p (b , b ) of absolute values of the data transitions future &ngr; bits and past &tgr; bits, for estimating the channel characteristics of the sampled signal from the selected tap value and the data transition value; a timing recovery portion for controlling the sampling timing phase of the analog-to-digital converter using a phase gradient equal to p ( )&minus;p ( ), which is the difference between values of respective taps positioned symmetrically around the tap P of the modeling portion; an equalizer for compensating for the deteriorated characteristics of the output value of the analog-to-digital converter; and a detector for converting the output of the equalizer to a digital value, to detect the original signal. Therefore, an accurate timing phase can be found using a model in which a non-linear channel of a high-density digital magnetic storing device is expressed by transition pulses selected according to the future &ngr; bits and the past &tgr; bits, thereby reducing timing jitter and bias.

Non-linear signal receiver

A nonlinear equalizing apparatus used for a digital magnetic recording medium is provided. The nonlinear equalizing apparatus according to the present invention includes a linear filter for linear filtering the input value r,, a pattern dependent filter including 2,tap values selected by the respective patterns (b,,b,) of future v and past &tgr; bit data transition absolute values and N taps p,(b,,b,) for outputting the value obtained by multiplying the selected tap value with the current transition (x,), and (wherein, x,&equals;(a,&minus;a,)/2&isin;&lcub;&minus;1, 0, &rcub;, b,&equals;&verbar;x,&verbar;&isin;&lcub;0, 1&rcub;, b,&equals;(b,b,. . . b,), b,&equals;(b,b,. . . b,), n&equals;0, 1, 2, . . . , N, and N is a predetermined integer not less than 1&plus;v) a detector for obtaining an error value e,by a subsequent equation, with respect to all combinations of current and future data sequences

Nonlinear equalizing apparatus

A signal detection device and method of a data recording/reproducing apparatus. The signal detection device of a data recording/reproducing apparatus for recording/reproducing a digital signal U.sub.k having an arbitrary integer time k as an index, includes: an analog-to-digital converter (ADC) for converting an analog signal from which external band noise is removed after being reproduced from the data recording/reproducing apparatus, into a digital signal; a filter for modifying the digital signal converted by the analog-to-digital converter (ADC) into a signal having a predetermined spectral shape; and a Viterbi detector for detecting the spectrum signal modified by the filter as the data recorded in the data recording/reproducing apparatus. Therefore, after equalizing a signal into a spectrum expressed by 2+D+D.sup.2 +D.sup.3, which is similar to the spectrum of an optical recording/reproducing apparatus, the maximum likelihood (ML) is detected by the Viterbi detector. Accordingly, noise scarcely increases and loss by intersymbol interference is overcome, so that the signal can be detected with reliability.

Signal detection method of data recording/reproducing apparatus and

A method and device for detecting data of a data storing unit includes an analog/digital converter for outputting a symbol signal r.sub.k by sampling an analog signal r(t) with a sampling clock, an equalizer for outputting z.sub.k by equalizing the output r.sub.k of the analog/digital converter, a data detector for detecting symbol data a.sub.k from the equalized output z.sub.k, and a clock recovering portion for correcting frequency and phase of the sampling clock, the clock recovering portion performing the correction at an edge of a symbol data a.sub.k. Therefore, it is possible to reduce errors in detecting data and to effectively detect the data with a far better performance that conventional technology and to restore a sampling clock by limiting a sampling clock recovering process to operate only at the edge of the symbol data.

Method for detecting data and device therefor of data storing unit

An apparatus for detecting and removing an additive disturbance from a signal in a data transmission channel, and an method therefor. The apparatus includes: a disturbance detector which detects whether a disturbance exists in an input signal; a canceling signal generating portion which, when a disturbance is detected by the disturbance detector, generates a canceling signal beginning at the same time as the disturbance, based on a predetermined period of the input signal; and a disturbance remover which subtracts the canceling signal from the input signal to remove the disturbance. Therefore, the canceling signal is generated based on both the output and input signals, thereby precisely removing the disturbance.

Apparatus for removing additive disturbance from data channel and method

Data detection method and apparatus in a data storage device are provided. The data detection apparatus includes: a Random Access Memory (RAM) updating device for obtaining the average characteristic of the equalization signal z.sub.k from the symbol data a.sub.k and storing and updating the obtained result; threshold value calculator for calculating an optimal threshold value with respect to each data pattern from the average characteristic of the equalization signal z.sub.k updated in the RAM updating device; and a detector for detecting the value of the symbol data a.sub.k by comparing the equalization signal z.sub.k with the threshold value calculated in the threshold value calculator. Thus, a signal is detected by obtaining an average characteristic of a signal according to a data pattern and then using an optimal threshold value to detect the signal so that a signal having considerable non-linear distortion and a Direct Current (DC) offset can be reliably detected.

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Seongnam, South Korea

Yung-soo Kim