Electronics and Telecommunications Research Institute

Yun-Jeong Song

Ho-Jin Lee

Young-Wan Kim

Deock-Gil Oh

Nae-Soo Kim

Nam-Ho Hur

Soo-In Lee

Jong-Suk Chae

Soon-Ik Jeon

Jun Young Heo

Hyoungsoo Lim

Pan-Soo Kim

Pansoo Kim

Sang-Woon Kwak

Myung-Sun Baek

Young-Su Kim

Joungil Yun

Han-Seung Koo

Byoung-Hak Kim

Yang-Su Kim

Kyu-Tae Yang

Doh-Wook Kim

Bongho Lee

PanSoo Kim

Joong-Gon Ryoo

Provided is an apparatus for transmitting a signal based on a non-uniform inter-symbol interference (ISI) pattern, the apparatus that may transmit an output signal generated by modulating an input signal based on a parameter sequence to be used to control an interference pattern and a position of a transmission signal for each symbol using a faster than Nyquist (FTN) scheme.

Communication apparatus and method

Provided are an apparatus for estimating a phase error and a phase error correcting system using the phase error estimating apparatus. The apparatus includes: a probability value estimating unit for estimating a negative log probability value for each transmission symbol by transforming a soft output information transferred from the outside to a log A posterior probability ratio (LAPPR) value; an APP value calculating unit for calculating a posterior probability (APP) value by applying a negative exponential function to the transmission symbol; an average value deciding unit for deciding an average value for each transmission symbol using the probability information entirely, partially, or selectively according to a probability information type; and a symbol phase estimating unit for estimating a phase of a symbol based on the decided average value.

Apparatus for estimating phase error and phase error correction system using the same

Provided is a channel bonding receiving apparatus and method for expanding a channel bonding receiving band in a cable modem. The channel bonding receiving apparatus includes a channel bonding dividing unit for dividing a channel bonding broadband signal into a plurality of band signals and extracting a corresponding channel bonding signal from each of the divided band signals; and a channel routing unit for routing each of the extracted channel bonding signals to a corresponding demodulator.

Channel bonding receiving apparatus and method for expanding channel bonding receiving band

Provided are an apparatus for estimating frequency offset from received signal and method for the same. The apparatus and method estimates frequency offset precisely without increment of autocorrelator by performing moving average filtering on a noised signal to thereby alleviate jitter. The frequency offset estimating apparatus includes: moving average filter for alleviating jitter of received signal; multiplier for multiplying a filtered signal by conjugate complex operanded pilot signal; phase-rotation value calculator for calculating a phase-rotation value from multiplicand operanded signal by using of symbol delay and an autocorrelation function; frequency offset estimator for estimating frequency offset from the phase-rotation value based on a smoothing function multiplication.

Apparatus for estimating frequency offset from received signal and method for the same

An apparatus and a method for controlling a gain of I-channel signal and compensating Q-channel signal in response to the gain imbalance based on the gain-controlled I-channel signal as a reference channel signal is disclosed. The apparatus includes: an auto gain controller for controlling a gain of a signal selected from the I-channel signal and the Q-channel signal to have a predetermined amplitude, thereby generating a gain-controlled signal; a detector for detecting a gain imbalance between the gain-controlled signal and the remaining channel signal; and a compensator for compensating the gain imbalance of the remaining channel signal based on the detected gain imbalance.

Apparatus and method for compensating I/Q imbalance based on gain-controlled reference channel in orthogonal frequency division multiplex

The present invention provides an apparatus for compensating a phase difference of a receiver, the apparatus including: an accumulating unit for accumulating a radio frequency (RF) input signal and generating an accumulated RF signal in order to minimize an effect of a background noise of the RF input signal; a early-local oscillating unit for generating a phase-early local oscillated signal based on a local oscillated signal of the receiver; a late-local oscillating unit for generating a phase-late local oscillated signal based on a local oscillated signal of the receiver; a phase early-late compensating unit for compensating a phase early-late based on the accumulated RF input signal and the phase-early and phase-late local oscillated signals; a look-up table data mapping unit for controlling a phase of the local oscillated signal with respect to a phase difference; and a feedback transmitting unit for transmitting a phase compensating data to the local oscillator.

Apparatus for compensating phase of receiver and method thereof

An apparatus and method for compensating an imbalance of phase and gain between I-channel and Q-channel by using variable loop gains is disclosed. The apparatus includes: a phase error generator for generating a phase error signal by using the I-channel signal and the Q-channel signal; an average value calculator for calculating an average value of the phase error signal; a comparator for comparing the average value with a predetermined threshold; a selector for selecting a loop gain value among a set of loop gains based on the comparison result; a phase imbalance generator for generating a phase imbalance by using the selected loop gain value; and a compensator for compensating the Q-channel signal based on the phase imbalance.

Method and apparatus for compensating I/Q imbalance by using variable loop gain in quadrature demodulator

Disclosed is a quadrature demodulator for high-speed wireless communication, which comprises: an A/D converter for converting received signals into digital signals; a signal recovery unit for recovering carriers and symbol timing from the signals converted by the A/D converter; a decision unit for detecting recovered signals output by the signal recovery unit, and performing a decision process on them; an I/Q gain imbalance detector for detecting gain imbalances of the I and Q-phase components from the recovered signals, and outputting an I/Q gain compensation value for compensating for the gain imbalances; and an I/Q gain compensator, provided between the A/D converter and the signal recovery unit, for reflecting the I/Q gain compensation value output by the I/Q gain imbalance detector to the received signals.

Quadrature demodulator for compensating for gain and phase imbalances between in-phase and quadrature-phase components

Disclosed is a method for detecting and correcting amplitude and phase imbalances between in-phase (I) and quadrature-phase (Q) components in a high-speed wireless communication quadrature demodulator, which comprises: a) comparing an input signal with a signal determined by a quadrant to which the input signal belongs, and detecting imbalances between I and Q components with respect to the input signal; and b) using the imbalances detected in a) to correct the input signal. The present invention prevents distorting of the demodulator's performance caused by the imbalances to between I and Q components and increases application to high-speed wireless communication.

Growing community of inventors

Daejon, South Korea

Yun-Jeong Song