Samsung Electronics Co., Ltd.

Electronics and Telecommunications Research Institute

Yonsei University

Myeong-Cheol Shin

Dong-Seung Kwon

Chung-Yong Lee

Seung-Joon Lee

Young-Seog Song

Jong-Ee Oh

Fei Tong

In-Kyeong Choi

Jacob Christopher Sharpe

Jeongtaek Lee

Tae-Sung Kim

Yu-Ro Lee

Seung-Hoon Nam

Kwang-Jae Lim

Chungyong Lee

Hyoung-Soo Lim

Seung-Ku Hwang

Seong-Rag Kim

Jin-yong Chung

Choong-Il Yeh

Myoung-Seog Kim

A receiver configured to receive a frequency-modulated transmission having a preamble and a corresponding method are provided, the receiver having a buffer coupled to an input terminal for receiving the transmission, a time-to-frequency transformer coupled to the buffer, an energy aggregator coupled to the transformer, a preamble detector coupled to the aggregator, and a symbol synchronizer coupled to the detector; the method including receiving a sequence of time-domain frequency-modulated samples, transforming the sequence of time-domain samples into a spectrum of frequency-domain data, and matching an actual energy distribution over a plurality of discrete frequencies in the frequency-domain data with an expected energy distribution of the preamble to determine frequency error.

Synchronization for low-energy long-range communications

An apparatus and a method are provided for receiving a signal in a communication system supporting a Gaussian frequency shift keying (GFSK) modulation scheme. The method includes receiving the signal; and estimating a codeword vector by performing a signal detecting operation based on a GFSK-maximum likelihood sequence estimation (MLSE) scheme, which is based on a GFSK modulation scheme and an MLSE scheme, on the received signal. States of a Viterbi trellis that are used in the GFSK-MLSE scheme are determined based on the GFSK modulation scheme.

Apparatus and method for receiving signal in communication system supporting Gaussian frequency shift keying modulation scheme

To demodulate a quadrature amplitude modulation (QAM) signal, a reception point is determined corresponding to a symbol in the QAM signal that is received where the symbol is mapped to one reference point of a plurality of reference points in a rotated constellation and the plurality of reference points are represented by an in-phase (I) coordinate and a quadrature-phase (Q) coordinate. A plurality of candidate points corresponding to a portion of the plurality of reference points are selected based on distances between the reception point and the respective reference points. The reception point is demapped by calculating a plurality of log-likelihood ratios based on the plurality of candidate points, the plurality of log-likelihood ratios corresponding to bits of data represented by the reception point.

Method of demodulating a quadrature amplitude modulation signal and method of data communication

The present invention relates to a multi-input multi-output (MIMO) system for enhancing transmission performance. The MIMO system uses space-time encoding and transmit antenna selection methods, and includes a transmitter () and a receiver (). The transmitter () includes N transmit antennas (--) that are more than M transmit antennas (--) used for transmitting a signal to space channel, selects the M transmit antennas (--) among the N transmit antennas (--), and transmits symbol by space-time encoding the symbol. The receiver () includes M receive antenna (--) for receiving a signal from the space channel, detects an information symbol by using the signal received through the receive antenna (--), generates transmit antenna selection information for selecting M transmit antennas (--) among transmit antennas (i--) with reference to a channel estimate, and returns the information to the transmitter.

Multi-input multi-output system for enhancing transmission performance

Respective codewords of quantization codebooks corresponding to a number of data streams are selected based on channel information estimated by a received training symbol. A stream mode is selected among stream modes to determine a modulation method applied to each data stream. The data stream is detected by using the codeword corresponding to the quantization codebook of the data stream corresponding to the selected stream mode as a precode matrix, and the detected data stream is modulated. In this case, a receiving apparatus performs a feedback operation so that indexes of the selected stream mode and the codeword used as the precode matrix may be transmitted to the transmitting apparatus. The transmitting apparatus selects the number of transmitted data streams and the modulation method based on the transmitted index of feedback streams by the feedback operation.

Transmitting apparatus and method, and receiving apparatus and method in multple antenna system

In a method for optimizing a codebook including a quantized channel between a base station transmitter and a portable terminal: a) select the codebook to be optimized; b) a steepest descent algorithm is applied to respective codewords of the codebook selected in a), wherein the codewords are transformed so that a correlation between the codewords is minimized, and a function indicating the correlation between the codewords is differentiated and is multiplied by a predetermined step size and is used for a parameter for generating a new codeword in the steepest descent algorithm; c) it is determined whether the codebook including the codewords transformed in b) is optimized; and d) the codebook is stored when it is determined in c) that the codebook is optimized.

Method and device for optimizing codebook for quantized precoder by using steepest descent algorithm

An apparatus and method for performing channel estimation in an OFDM (Orthogonal Frequency Division Multiplexing) system using multiple antennas, and a method for performing channel estimation using received sub-carriers in an OFDM system for receiving a sub-carrier having a training symbol and another sub-carrier having no training symbol comprising the steps of: a) differently setting a weight associated with a reliability of the sub-carrier having the training symbol and a weight associated with a reliability of the sub-carrier having no training symbol, b) measuring channel estimation errors associated with individual received sub-carriers, and c) performing channel estimation using the measured channel estimation errors and the set weights.

Apparatus and method for performing channel estimation in an orthogonal frequency division multiplexing (OFDM) system using multiple antennas

A processor on which a software-based interleaver is run performs interleaver generation, which is split into two parts to reduce the overhead time of interleaver changing. First, preprocessing prepares seed variables, requiring a small memory. Second, on-the-fly address generation generates interleaved addresses through simple adding and subtracting operations using the seed variables.

Turbo decoder and turbo interleaver

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Seoul, South Korea

Myeong-Cheol Shin