Electronics and Telecommunications Research Institute

Lee, Hyo-jin

Byung-Jang Jeong

Hyun-Kyu Chung

Jae-Young Ahn

Taegyun Noh

Sung-Hyun Hwang

Jung-Sun Um

Hyo-Jin Lee

Hyojin Lee

Sung-Jin Yoo

Minjoong Rim

Jae Young Ahn

Hyun Kyu Chung

Myung-Sun Song

Hee-Soo Lee

Tae-Gyun Noh

Jae-Ick Choi

Jae-Kyun Kwon

In-Sook Park

Jinho Choi

Disclosed herein are a method and a system for performing initial ranging in a cognitive radio network The method for performing initial ranging in a cognitive radio network includes: detecting signals received in one or more ranging sections; estimating a tint time offset based on a correlation between subcarrier indices of the signals detected in the one or more ranging sections; estimating a second time offset based on correlations for the signals detected in the one or more ranging sections and a plurality of codes that are predetermined and detecting an initial ranging code among the plurality of codes; and estimating a time offset of a CPE performing initial ranging with the detected initial ranging code using the first time offset and the second time offset that are estimated.

Method and system for performing initial ranging in cognitive radio network

Disclosed herein are an apparatus and a method of estimating a channel in consideration of a residual synchronization offset. The apparatus of estimating a channel in consideration of a residual synchronization offset includes: a channel estimating unit estimating the channel using pilots scattered over a plurality of OFDM symbols and calculating a first channel estimated value as the estimation result, in the case in which an OFDM symbol estimating the channel and an OFDM symbol compensating for the channel are different from each other; and a phase reflecting unit calculating a phase generated by the residual synchronization offset in proportion to a difference between a channel estimation time and a channel compensation time, reflecting the calculated phase in the first channel estimated value, and calculating a second channel estimated value as the reflection result.

Apparatus and method of estimating channel in consideration of residual synchronization offset

Provided are a pilot transmitting apparatus and method capable of selectively using an OFDMA scheme and an SC-FDMA scheme. The pilot transmitting apparatus includes a pilot inserter for inserting a pilot signal in a modulated symbol and inserting a cyclic prefix code for the inserted pilot signal, an FFT processor for receiving symbols with a pilot inserted thereto from the pilot inserter and performing an FFT process on the received symbols, an IFFT processor for receiving the transformed data from the FFT processor and performing an IFFT process on the transformed data, a mapping processor for mapping the output of the FFT processor to input positions of the IFFT processor to load the frequency domain transformed data on predetermined sub-carriers, and a cyclic prefix inserter for inserting a cyclic prefix code for the output of the IFFT processor.

Pilot transmitting apparatus and method for SC-FDMA system

The present invention relates to a method and device for detecting a transmission signal on the basis of a received signal by applying a division and detection algorithm. An embodiment of the invention provides a method of detecting a transmission signal including: obtaining a unitary matrix and an upper triangular matrix by performing a sorted QR-decomposition algorithm with respect to a matrix indicating a channel state; calculating a vector y by multiplying a transpose matrix of the unitary matrix by the received signal Y; dividing the upper triangular matrix R into a plurality of sub-upper triangular matrices and dividing the calculated vector y into a plurality of sub-vectors so as to correspond to the divided plurality of sub-upper triangular matrices; and detecting a lattice point corresponding to each of the divided sub-vectors using the divided plurality of sub-upper triangular matrices.

MIMO system method and device using sorted QR-decomposition (SQRD) for detecting transmission signal with division detection

Provided is a technology for extending a guard interval for individual user equipment in an OFDMA system. The transmitting apparatus includes: a guard interval extension processor for generating symbols with a guard interval extended by copying a part of a current symbol and pasting the copied part to a last part of a previous symbol; a Fourier Transform (FT) processor for receiving the processed symbols from the guard interval extension processor and performing an FT process on the received processed symbols; an Inverse Fast Fourier Transform (IFFT) processor for performing an IFFT process on the FT processed symbols from the FT processor; a mapping processor for mapping outputs of the FT processor to input points of the IFFT processor to load the FT processed frequency-domain data on corresponding sub-carriers; and a cyclic prefix inserter for inserting a cyclic prefix code to output of the IFFT processor.

Transmitter for extending guard interval for individual user equipment in OFDMA systems

Disclosed are a base station, a relay station, and a terminal according to a method for designing a cellular system for improving resource usage efficiency by reducing interference between relay stations and interference between the base station and the relay station. The relay station gets control signals that terminals served by the base station transmit, and registers terminals, levels of the control signals of which are bigger than a predetermined value, to a list of the interference terminals. The relay station checks an interference resource through resource allocation information of the base station, checks an available resource corresponding to a resource except the interference resource among a resource allocated by the base station, and allocates some of the available resource to the terminal.

Relay station, terminal and base station in cellular system, and method for relaying between terminal and base station

Provided are a detector for a multi-level modulated signal and a detection method using the same, and an iterative receiver for a multi-level modulated signal and an iteratively receiving method using the same. The detector includes: a channel estimator estimating a channel response of each of a plurality of bits included in at least one received signal based on multi-level modulation; a hard decision unit, for each bit, selecting at least one of a plurality of bits remaining by excluding the bit and performing a hard decision based on a pre-probability of the selected bit; and a reliability calculator calculating reliability of each of all the bits in the received signal based on the received signal from which the hard-decided bit component is cancelled and the estimated channel response. Accordingly, the computation amount according to detection can be reduced without the degradation of performance.

Detector for multi-level modulated signal and detection method using the same, and iterative receiver for multi-level modulated signal and iteratively receiving method using the same

Disclosed is a pilot signal transmitting/receiving device and method in a wireless communication system. When generating a pilot signal block that is shorter than the length of a data signal, a frequency for each predetermined pilot signal block is transitioned so as to guarantee frequency domain channel estimation performance. A cyclic prefix according to the length of the transitioned pilot signal is added to the pilot signal, a data signal is time division multiplexed together with the pilot signal, and a resultant signal is transmitted through an antenna. In advance to this, a position of a subcarrier for transmitting the pilot signal and the data signal is determined, a data signal is mapped on the determined subcarrier, and in this instance, diversity on the channel for a symbol is used to map the data signal on the transmission method using one of the localized FDMA (L-FDMA) channel and the distributed FDMA (D-FDMA) channel. Therefore, the frequency resolution in the frequency domain is maintained to thus provide high-quality channel estimation performance.

Device and method for transmitting and receiving pilot signal in wireless communication system

The present invention relates to a transmitter in a frequency division multiple access communication system. The transmitter generates a plurality of pilot symbols, and groups the plurality of pilot symbols into a plurality of groups according to a location of a subcarrier. In addition, the transmitter inverse fast Fourier transforms the pilot symbol in each group, and sequentially outputs a first pilot symbol sequence corresponding to each group. The transmitter generates a plurality of pilot blocks respectively corresponding to the plurality of groups, and converts the first pilot symbol sequence of each group into a second pilot symbol sequence of a corresponding pilot block among the plurality of pilot blocks.

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Daejeon, South Korea

Byung-Jang Jeong