Electronics and Telecommunications Research Institute

University-industry Cooperation Group of Kyung Hee University

Yun-Hee Kim

Kwang-Soon Kim

Sang-Hyun Lee

Kyung-Hi Chang

Jae-Young Ahn

Kyu-Jong Hwang

Sunghwan Kim

Jong-Seon No

Yong-June Kim

Chang-Joo Kim

Myung-Sun Song

Gwangzeen Ko

Sung-Hyun Hwang

Yong-Soo Cho

Jung-Sun Um

Kyung-Won Park

Jung-Sun 408-205 Jugong-4Danji Apt 908 Um

Disclosed is a decoding apparatus for LDPC (Low-Density Parity-Check) codes when receiving data encoded with LDPC codes on a channel having consecutive output values, and a method thereof. The decoding method for LDPC codes uses sequential decoding and includes the following steps: (a) the nodes are divided according to a parity-check matrix into check nodes for a parity-check message and variable nodes for a bit message; (b) the check nodes are divided into a predetermined number of subsets; (c) the LDPC codeword of each subset for all the check nodes is sequentially decoded; (d) an output message is generated for verifying validity of the decoding result; and (e) the steps (b), (c), and (d) are iteratively performed by a predetermined number of iterations.

Decoding apparatus for low-density parity-check codes using sequential decoding, and method thereof

Disclosed is an adaptive transmit and receive method and device in a multiple-antenna wireless communication system. A transmit mode comprises different main transmit modes each of which includes one or both of a sub-transmit mode based on STBC and a sub-transmit mode based on SM. A receiver calculates an STBC performance parameter and a SM performance parameter, and a transmitter uses the parameters to determine a main transmit mode with maximum data rates and select a sub-transmit mode for minimizing power consumption. The transmitter channel-encodes, modulates and antenna-maps input data according to the selected transmit mode, and outputs results to the receiver. The receiver antenna/symbol-demodulates and channel-decodes the received data.

Adaptive transmission and receiving method and device in wireless communication system with multiple antennas

In the resource mapping method for data transmission, a time-frequency resource of a slot interval including OFDM symbols is divided into traffic channels and shared among the subscribers, the traffic channel including resource blocks uniformly distributed in the whole transmit frequency band, the resource block including consecutive subcarriers of consecutive received symbols having at least one inserted pilot symbol. The pilot symbols and the channel-encoded and modulated data symbols are processed by time-frequency mapping according to the resource-block-based mapping method to generate received symbols. The receiver separates the received symbols by subscribers according to the resource-block-based mapping method in a frequency domain, and performs iterative channel estimation, demodulation, and decoding by using the pilot and a data reference value after decoding for each traffic channel.

Apparatus for OFDMA transmission and reception for coherent detection in uplink of wireless communication system and method thereof

Disclosed is an adaptive transmitting and receiving device and method using frequency division duplexing. A transmitter transmits a preamble or a pilot to a receiver. The receiver estimates a received SNR from the preamble or pilot, determines parameters (received log likelihood ratio parameters) of determining the distribution of the received log likelihood ratio, and feeds them back to the transmitter. The transmitter adaptively determines an antenna method, a modulation method, and a transmit power according to the parameters, and adaptively transmits traffic data to the receiver according to the determined antenna method, the modulation method, and the transmit power.

Adaptive transmitting and receiving device and method in wireless communication system using frequency division duplexing

Disclosed is an apparatus and method for erasure detection and soft-decision decoding in a cellular system receiver. In the present invention, a complex channel gain and a noise variance of a received symbol from a cellular system transmitter are estimated, and an erasure symbol (a symbol with high power interference) is detected by comparing a threshold value according to the estimated complex channel gain or noise variance with power of the received symbol. Log-likelihood ratios corresponding to constituent bits of the detected erasure symbols are allowed to be 0, and the log-likelihood ratios of the constituent bits of the other received symbols are calculated. A soft-decision decoding operation of received bits is performed with the calculated log-likelihood ratios.

Apparatus and method for erasure detection and soft-decision decoding in cellular system receiver

An LDPC code encoding apparatus includes: a code matrix generator for generating and transmitting a parity-check matrix comprising a combination of square matrices having a unique value on each row and column thereof; an encoding means encoding block LDPC codes according to the parity-check matrix received from the code matrix generator; and a codeword selector for puncturing the encoded result of the encoding means to generate an LDPC codeword. The code matrix generator divides an information word to be encoded into block matrices having a predetermined length to generate a vector information word. The encoding means encodes the block LDPC codes using the parity-check matrix divided into the block matrices and a Tanner graph divided into smaller graphs in correspondence to the parity-check matrix.

Apparatus for encoding and decoding of low-density parity-check codes, and method thereof

Disclosed is a transmitting and receiving method for reducing a time-varying channel distortion in an orthogonal frequency division multiplex (OFDM) system. In the present invention, the transmitter defines M sub-channels in one data group, mathematically analyzes a change of channel for each path causing a time-varying channel distortion in a high-speed mobile environment by approximation, calculates a weight value based on the mathematical analysis and assigns the calculated weight value to transmit data of each sub-channel. Subsequently, the receiver combines the signals of these M sub-channels and demodulates the combined signals. Accordingly, the present invention greatly reduces a distortion caused by the time-varying channel to improve a bit error rate and a channel estimation performance.

Transmitting and receiving method for reducing distortion caused by a time-varying channel in an orthogonal frequency division multiplex system

Disclosed is a receiver digital filter for a digital IF signal processor suitable for the specification of each communication standard in a communication system that supports at least one communication standard. The filter for each standard is constructed as one block, and includes a block for externally implementing the constructed block. The coefficient of the digital filter constructed in one block is implemented with an external input or an internal filter coefficient calculator by a basic filter building block. In this manner, the common resources required in the digital filter used in each communication standard are shared, and only the additionally required resources are selectively implemented. Since the shared resources are calculated by dynamic programming, a considerably smaller number of additional resources are required.

Digital filter for software-defined radio system, digital intermediate frequency signal processing apparatus having the digital filter, and method thereof

Disclosed is an implementation method for simplifying a complicated message-passing function in a decoder for decoding block codes encoded with low-density parity-check (LDPC) codes and only using a summator and a shifter to simplify the hardware structure of the decoder, in which method the input interval of the message-passing function for binary representation of a message input is divided and the respective divided intervals are linearized to allow the calculation of the output of the message-passing function without using a memory. Based on the fact that the message-passing function is similar in structure to an exponential function, the linearized intervals are set to make the maximum value expressible in each digit of the binary representation as the boundary of the intervals.

Growing community of inventors

Daejeon, South Korea

Yun-Hee Kim