Samsung Electronics Co., Ltd.

Yonsei University

Electronics and Telecommunications Research Institute

Qualcomm Incorporated

Industry-academic Cooperation Foundation

Keum-Chan Whang

Kwang-Soon Kim

Young-Jo Ko

Jae-Young Ahn

Jung-Hyoung Kwon

Yung-Soo Kim

Dong-Ho Kim

Myeon-Gyun Cho

Hyo-Yol Park

Jae-Won Kang

Hyuck-Chan Kwon

Sang-min Lee

Sun-young Lee

Tak-Ki Yu

Chan-Soo Hwang

Jong-Yoon Hwang

Yu-Seok Kim

Ye-Hoon Lee

The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.

Adaptive transmission device using limited feedback information in a mobile communication system, and a method thereof

A method and an apparatus for transmitting a signal in a communication system are provided. An information vector is encoded according to a Low Density Parity Check (LDPC) encoding scheme, thereby generating an LDPC codeword. Minimum surviving check nodes are reserved for recovery of punctured nodes in the LDPC codeword. A check node is selected having a smallest cost function from among unreserved check nodes. A variable node is selected being unpunctured and having a smallest cost function from among variable nodes connected to the selected check node. The selected variable node is punctured when the selected variable node is not connected to the reserved check node. A stopping set check is performed when the selected variable node is connected to the reserved check node. The variable node is punctured when the stopping set check has been successfully performed. The check node is selected until there remains no variable node to be punctured and puncturing the variable node.

Apparatus and method for signal transmission/reception in a communication system

A method for transmitting a signal in a wireless communication system. The method comprises the steps of: grouping two subcarriers having different channel characteristics; identifying a number of all cases occurring when either equal symbols or different symbols, among symbols determined upon applying a first modulation scheme, are mapped to the two subcarriers; and mapping two subcarriers corresponding to each of the number of all cases to one symbol according to a second modulation scheme, and transmitting the signal, wherein a modulation order of the second modulation scheme is two times higher than a modulation order of the second modulation.

Method for transmitting signal in wireless communication system

A method for puncturing a Low Density Parity Check (LDPC). The method includes a) setting a codeword length and the total number of bit nodes to be punctured; b) selecting a check node (or check nodes) with highest priority excluding check nodes completely checked in a current round; c) selecting a bit node (or bit nodes) with a highest priority excluding bit nodes completely checked among bit nodes connected to the selected check node (or check nodes); d) determining whether the selected bit node is a bit node to be punctured, that is, it is not systematic, not set by a puncturing prohibition flag; e) puncturing an associated bit node if the selected bit node is the bit node to be punctured, setting unpunctured bit nodes connected to the selected check node by a puncturing prohibition flag, decreasing the number of remained bit nodes to be punctured by 1 and increasing the number of connected punctured node of associated check node by 1; f) determining whether the number of remaining bits to be punctured is greater than 0; and g) returning to step b) if the number of remaining bits to be punctured is greater than 0, and ending a puncturing process if the number of remaining bits to be punctured is not greater than 0.

Method for puncturing a low density parity check code

An apparatus and method for estimating a frequency offset in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided. Two time domain signals are generated from one received OFDM symbol through two observation windows with different delay times. The two time domain signals are compensated for a candidate frequency offset. A discrete Fourier transform process and a phase compensation process in a frequency domain are performed. A difference between two frequency domain signals compensated for a phase difference is computed with respect to each candidate frequency offset. For all candidate frequency offsets, difference values are compared with each other. A candidate frequency offset mapped to a minimum difference value is detected as an optimal frequency offset. The frequency offset can be more exactly estimated without consuming a bandwidth and increasing hardware complexity of a receiver.

Apparatus and method for estimating frequency offset in orthogonal frequency division multiplexing system

Disclosed is a method for generating a space-time trellis code (STTC) for maximizing space-time diversity gain and coding gain in a mobile communication system including at least two transmission antennas and generating a second number of STTC codes with an information data bit stream upon receiving the information data bit stream comprised of a first number of bits. The method comprises calculating a minimum effective length for each of the STTC codes; calculating product distances between all STTC codes having the same length as the minimum effective length, wherein for each of pairs of all initial states and all end states for each of the STTC codes, initial states are identical to end states; summing reciprocals of product distances between all the STTC codes for each of the STTC codes, and calculating minimum average product distances by determining a reciprocal of the summation result; and selecting an STTC code corresponding to a minimum average product distance having a maximum value among the minimum average product distances as an STTC code corresponding to the information data bit stream.

Apparatus and method for generating space-time trellis code for maximizing space-time diversity gain and coding gain in a mobile communication system

A novel and improved method and apparatus in a communication system (100) provides for efficient processing of received signals. The method and apparatus includes converting an encoded and spectrum spread received signal to received samples, determining a first channel estimate based on a first set of pilot signal samples. The first set of pilot signal samples are included in the received samples. The received samples are passed through a correlation and decoding process in accordance with the first channel estimate to produce decoded received samples. The decoded received samples are re-encoded and re-spreaded to produce re-encoded and re-spread samples. The re-encoded and re-spread samples are modified based on the first channel estimate to produce channel modified re-encoded and re-spread samples. The received samples pass through an interference cancellation that uses the channel modified re-encoded and re-spread samples to produce a new set of received samples.

Method and apparatus for interference cancellation in a communication system

A novel and improved method and apparatus for controlling signal power level in a communication system ( ) is provided by determining first and second signal to interference ratios of a received signal, respectively before and after an interference cancellation, determining a difference between the first and second signal to interference ratios, and determining, based on the difference, a signal to interference threshold for controlling power level of a signal transmitted from a source of the received signal.

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Seoul, South Korea

Keum-Chan Whang