Electronics and Telecommunications Research Institute

Kt Corporation

Jong-Soo Lim

Soo-In Lee

Sung-Ik Park

Heung-Mook Kim

Jae-Young Lee

Jae-Hyun Seo

Ho-Min Eum

Yong-Tae Lee

Hyun Jun Lee

Young-Su Kim

Jae-Hwui Bae

Ju-Yeun Kim

Hyun Woo Lee

Soo In Lee

Heung Mook Kim

Sung Ik Park

Hyoung-Soo Lim

Gwang-Soon Lee

Kug-Jin Yun

Hyoung-Nam Kim

Bong-Ho Lee

Yang-Su Kim

So-Ra Park

Chung-Pyo Hong

Won-Jin Park

Kyung-Sik Son

Ji-Bong Lee

Wan-Jin Kim

Tae-June Chae

Provided are an on-channel repeater and an on-channel repeating method. The on-channel repeater includes: a receiving means for receiving a Radio Frequency (RF) signal; a subtracting means for subtracting a replica of feedback signals from the signal received by the receiving means; a replica generating means for calculating the replica based on the signal acquired from the subtraction in the subtracting means and feeding back the replica to the subtracting means; an inverse channel estimating means for estimating inverse of a reception channel based on the signal acquired from the subtraction in the subtracting means and generating filter tab coefficients; a first adaptive filtering means for compensating for channel distortion of the signal subtracted by the subtracting means based on the filter tab coefficients generated in the inverse channel estimating means; and a transmitting means for converting a signal whose channel distortion is compensated by the first adaptive filtering means into an RF signal and performing radio transmission.

On-channel repeater and on-channel repeating method

Provided is an apparatus and method for analyzing identification (ID) signals by converting radio frequency (RF) signals which are transmitted with an ID signal added thereto by a transmitting part, e.g., a plurality of transmitters or repeaters, into signals of a desired band; creating ID signals that are identical to the ID signals added to the RF signals; calculating correlation values between the converted signals and the created ID signals based on partial correlation; and extracting channel profile of multi-path signals caused by a channel between the transmitting part and the ID signal analyzing apparatus from the correlation value. The technology of the present research is applied to broadcasting and communication.

Apparatus and method for analyzing identification signal based on partial correlation

Provided is an identification signal analyzing apparatus and method for compensating power of a channel profile occurring at a conventional identification signal analyzing apparatus by using a power compensation. The identification signal analyzing apparatus includes: an identification signal generator for generating an identification signal identical to a known identification signal inserted by a transmission device; a partial correlator for calculating a correlation value between a received signal including the known identification signal inserted by the transmission device and the identification signal generated by the identification signal generator through a partial correlation; a power compensator for compensating power of the correlation value calculated by the partial correlator; and a channel profile extractor for extracting a channel profile from the correlation value compensated by the power compensator.

Identification signal analyzing apparatus and method for compensating for separation and attenuation of channel profile

Disclosed is a system for transmitting encrypted broadcast signals to different transmitters on a single frequency network (SFN) in a digital broadcasting system. The system for transmitting encrypted broadcast signals on the SFN includes: a main broadcasting system for transmitting encrypted broadcast signals including data streams and transmitter identification information (TII) through a main broadcasting network; a repeating system for amplifying encrypted broadcast signals of the main broadcasting network and transmitting the amplified broadcast signals, or modulating and amplifying streams input by the main broadcasting system through a private line and repeating broadcast signals of the main broadcasting system through a repeating network; and a decrypting key provider for receiving a decrypting key value from the main broadcasting or repeating system and transmitting a user authentication and decrypting key to a charged subscriber terminal through a mobile communication network.

System for transmitting the scrambled broadcast-signals in single frequency network, and a method thereof

Provided is a channel estimation apparatus and method using a linear/nonlinear average in a wireless communication system. The present research provides a channel estimation apparatus and method for estimating a channel between a transmitter and a receiver from a pilot-inserted OFDM signal and linearly or nonlinearly averaging the estimating channel, thereby preventing the equalizer performance from being degraded by noise component of the estimated channel and noise amplification caused by deep fading. The channel estimation apparatus includes: a channel estimation unit configured to estimate a channel coefficient of a channel between a transmitter and a receiver from a pilot-inserted carrier signal according to pilot arrangement; and a linear/nonlinear averaging unit configured to linearly or nonlinearly averaging the estimated channel coefficient, thereby preventing an equalizer performance from being degraded by noise component existing in the channel and noise amplification caused by deep fading.

Channel estimation apparatus and method using linear/nonlinear average in wireless telecommunication system

Provided are an apparatus and method for compensating a feedback path distortion in a digital broadcasting signal. The apparatus for improving a performance of a pre-equalizer in a transmitter of a digital broadcasting system having a feedback path for adaptively generating a filter coefficient of the pre-equalizer, includes a reference signal generator for generating a reference radio frequency (RF) signal, a feedback path estimator for estimating transmission band characteristic information for the feedback path based on the reference RF signal generated from the reference signal generator, and a feedback path compensator for compensating a demodulated signal transferred through the feedback path based on the estimated transmission band characteristic information from the feedback path estimator and generating a filter coefficient of the pre-equalizer.

Apparatus and method for compensating feedback path distortion

An on-channel repeating apparatus and method is provided. The method includes subtracting a replica of a feedback signal from a signal received from a main transmitter or another repeating apparatus; demodulating and equalizing the signal to remove noise, a multipath signal, and the remaining feedback signal from the signal; inserting identification signal having good correlation properties into the signal; modulating the signal; and transmitting the modulated signal.

On-channel repeating apparatus and method

Provided are a distributed repeater for repeating output signals identical to input signals through a channel different from that of main transmitter signals but identical to channels of other distributed repeaters, and a distributed repeating method thereof. The distributed repeater includes: a pre-processing unit configured to receive a radio frequency (RF) signal transmitted from an external device and demodulate the RF signal into a baseband signal; an equalizer configured to equalize the baseband signal to correct a distortion occurring on a transmission channel; an identification signal generation and insertion unit configured to generate an identification signal for identification of the distributed repeater and network conditioning, and insert the identification signal in the equalized baseband signal; and a post-processing unit configured to convert the baseband signal from the identification signal generation and insertion unit into an RF signal, and send the RF signal.

Distributed repeater and distributed repeating method thereof

Provided is an apparatus and method for estimating inverse channel of a repeater's receiving channel, which ensures stability and causality by generating a time-domain filter coefficient having information on an inverse channel of repeater's receiving channel from a signal transmitted from a main transmitter or another repeater. The apparatus includes: a channel estimator for estimating a channel established by a transmission path from a received signal; an inverse minimum phase filter coefficient generator for generating inverse channel of a minimum phase channel from the estimated channel, and converting the inverse channel of the minimum phase channel into a time-domain filter coefficient; an inverse group delay filter coefficient generator for generating a time-domain filter coefficient by using the estimated channel and the minimum phase channel; and a combiner for generating an inverse channel of a receiving channel in a time domain by combining the filter coefficient and the filter coefficient.

Apparatus and method for estimating inverse channel of repeater's receiving channel

Provided is an on-channel repeater capable of removing feedback signals based on pilot partitioning, which can efficiently remove a feedback signal by quickly coping with even a situation in which a feedback channel changes rapidly, by reducing a filter-coefficient update interval, i.e., increasing the number of times of filter-coefficient creation, through pilot partitioning, and a method thereof. The on-channel repeater includes: a receiver for receiving a signal; a subtractor for subtracting a replica of a feedback signal from the signal received in the receiver to remove the feedback signal; a replica creator for creating a filter coefficient using pilot partitioning, creating a replica of the feedback signal using the created filter coefficient, and feeding back the created replica to the subtractor; and a transmitter for transmitting an output signal of the subtractor.

On-channel repeater for feedback capable of removing feedback signals based on pilot partitioning and method thereof

Provided is an on-channel repeater, which includes a receiver for receiving radio frequency (RF) signals; a subtractor for subtracting replica from the RF signals to thereby produce output signals of the subtractor; a repeating process unit for performing a repeating process onto the output signals of the subtractor; and a replica generator for calculating replica based on the output signals of the subtractor and the signals obtained after repeating process performed thereon and feeding the replica back to the subtractor.

Provided are an apparatus and method for selecting an optimal signal using auxiliary equalization in a diversity receiver. The optimal signal selecting apparatus includes: a plurality of sync recovery units for extracting sync information from baseband signals, which are candidate signals, except a baseband signal selected as a current optimal signal a plurality of auxiliary equalizers for channel-equalizing the candidate signals based on the extracted sync information; a plurality of SNR measuring units for measuring signal-to-noise ratios (SNRs) of the candidate signals inputted to the auxiliary equalizers and the candidates signals equalized in the auxiliary equalizers; and an optimal signal selector for selecting an optimal candidate signal from the candidate signals by using the extracted sync information and the measured SNRs, and replacing the optimal signal with the optimal candidate signal when reception quality of the current optimal signal is poor.

Apparatus and method for selecting optimal signal using auxiliary equalization in diversity receiver

Provided are an on-channel repeater for repeating an output signal the same as an input signal on channel by removing feedback signals caused by low isolation of a transmission/reception antenna by converting a transmitted Radio Frequency (RF) signal into a signal of a predetermined band and subtracting a replica of the feedback signal from the converted signal, and by compensating for channel distortion of a reception signal by estimating an inverse of reception channel from a signal acquired by removing the feedback signal, and an on-channel repeating method.

Provided are a beam combining and hybrid beam selection method that can improve digital broadcasting reception performance by combining more than two beam output signals (beam combination type) instead of simply selecting one of beam output signals (beam selection type), or even selecting an optimal method between the beam selection type and the beam combination type, and a digital broadcasting receiving apparatus using the same.

Beam combining and hybrid beam selection method for improving digital broadcasting reception performance, and digital broadcasting receiving apparatus using the same

There are provided a method for selecting an optimal beam to improve digital broadcasting receiving performance, and a digital broadcasting receiving apparatus using the same. The method includes the steps of: a) calculating a mainpath Signal to Multipath signal and Noise Ratio (SMNR) based on a channel impulse response for a plurality of beams which are formed according to steering directions from output signals of antennas, wherein the output signal of each antenna has different phase shift according to location of antenna element; b) selecting a predetermined number of beams having a high SMNR value by comparing the calculated SMNR value for respective beam; c) calculating a mainpath Signal to Dominant Multipath signal Ratio (SDMR) based on a channel impulse response corresponding to the selected beam; and d) selecting a beam output signal having the biggest SDMR value by comparing SDMR values calculated in selecting a predetermined number of beams.

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Daejon, South Korea

Jong-Soo Lim