Electronics and Telecommunications Research Institute

Jae Joon Park

Myung Don Kim

Sung Cheol Chang

Eunkyung Kim

Hyun Kyu Chung

Jae Sun Cha

Kwang Jae Lim

Seung-Kwon Baek

Chanho Yoon

Won Sop Kim

Heon Kook Kwon

Young-Hoon Kim

Hyun Jun Lee

Bong Hyuk Park

Juyul Lee

Pyeong Jung Song

Mun Geon Kyeong

Provided is a method for transmitting, by a transmitter, a first data having periodicity through a channel of an unlicensed band: The transmitter adjusts at least one of transmission timing of the first data and clear channel assessment (CCA) timing for the channel to occupy the channel. The transmitter determines whether the channel may be occupied by performing a CCA on the channel at the CCA timing. The transmitter transmits the first data through the channel at the transmission timing of the first data, when it is determined that the channel may be occupied.

Method and apparatus for managing allocation and usage of radio resource, method and apparatus for transmitting data through unlicensed band channel, and method and apparatus for managing access of radio resource

Method and apparatus for managing allocation and usage of radio resource, method and apparatus for transmitting data through unlicensed band channel, and method and apparatus for managing access of radio resouce

Disclosed are a base station and a channel access method performing a channel access in a unlicensed band. The channel access method includes: performing channel sensing at least once on a channel of the unlicensed band in a channel sensing period of a frame; and broadcasting a reservation signal for the channel when the channel is empty.

Radio channel access method and apparatus

A method and terminal for performing beamforming. The beamforming method of a terminal includes acquiring a beamforming signal, calculating a beamforming coefficient to correspond to locations of a transmitter and a receiver, based on the beamforming signal, acquiring sensor information of the terminal, estimating a channel parameter based on the sensor information, and determining a final beamforming coefficient based on the beamforming coefficient and the channel parameter.

Method and terminal for performing beamforming based on sensor information of terminal

A data relay method includes receiving a relay request from a BS, and when the relay request is accepted, relaying data between the BS and at least one external terminal, or the data relay method includes determining relaying between a first terminal among a plurality of terminals, and other remaining terminals excluding the first terminal among the plurality of terminals, and relaying data between the first terminal and the other remaining terminals.

Method of relay between devices

Disclosed is a radio-frequency front-end apparatus that can be used in wireless communication systems performing transmission/reception by using a single antenna. The radio-frequency transceiving front-end apparatus using passive elements in a wireless communication system includes: a transmitting unit's hybrid coupler configured to divide and output a transmission signal into two outputs having a phase difference of 90&#xb0;; a first circulator configured to receive a first output of the hybrid coupler through a first terminal thereof and output the received first output through a second terminal thereof; a second circulator configured to receive a second output of the hybrid coupler through a first terminal thereof and output the received second output through a second terminal thereof; and an output unit's hybrid coupler configured to receive transmission signals from the second terminal of the first circulator and the second terminal of the second circulator, and combine and output the received signals.

Radio-frequency transceiving front-end apparatus using passive elements in wireless communication system

The present invention relates to a multi-antenna radio channel measurement system and method for a two-way radio channel measurement, including: Control & Console Software to select a radio measurement mode, generate a probing signal for measurement, receive input parameters to be measured, and deliver the parameters to a baseband unit; a baseband unit (BBU) to set a transmission/reception frequency band and bandwidth and set a timing using the selected radio measurement mode and the received input parameters; a timing unit to synchronize a time with another radio channel measurement system to generate a transmission/reception synchronization signal, and provide the transmission/reception synchronization signal to the BBU; a transceiver unit (TRXU) to up-convert the probing signal for measurement and down-convert the reception channel signal; and a radio frequency (RF) front-end unit (RFFU) to switch to a suitable antenna according to a timing control signal of the BBU.

Multi-antenna radio channel measurement system and method for two-way radio channel measurement

A portable apparatus including: a Radio Frequency (RF) unit to control a frequency of a signal to be measured, to broadcast the signal to be measured through multiple transmission antennas, to control a frequency of a received signal, and to send the received signal to the baseband unit, the received signal being received through multiple receiving antennas; and a baseband unit to generate and transmit, to the RF unit, the signal to be measured, to measure wireless channels for each of the multiple transmission antennas and wireless channels for each of the multiple receiving antennas based on the received signal output from the RF unit, to calculate a correlation for each of the multiple transmission antennas, and to calculate a correlation for each of the multiple receiving antennas based on the wireless channels for each of the multiple transmission and receiving antennas.

Portable apparatus and method of measuring wireless channel and multiple antenna correlation

The present invention relates to a multi-antenna radio channel measurement system and method which generates a Time Division Duplex (TDD) timing signal and measures a two-way radio channel. The multi-antenna radio channel measurement system which measures a probing signal for measuring a radio channel, the multi-antenna radio channel measurement system including: a baseband unit alternately transmits the probing signal for measurement and receives the received channel signal to be measured based on a TDD synchronization time; a synchronization unit which obtains time synchronization with the other radio channel measurement system, generates a transmission/reception synchronization signal, and provides the transmission/reception synchronization signal to the baseband unit; a transceiver unit which up converts the probing signal for measurement and down converts the received channel signal; and a radio frequency (RF) front-end unit which switches suitable antennas according to a timing control signal of the baseband unit.

Multi-antenna radio channel measurement system and method which generates time division duplex timing signal and measures two-way radio channel

An apparatus for very high performance space-time array reception processing using chip-level beamforming and fading rate adaptation is disclosed. The space-time array receiving system includes a plurality of digital beamforming networks for forming beams of signals by spatial-filtering the signals, to thereby generate spatial-filtered signals; a plurality of demodulating unit for demodulating the spatial-filtered signals to generate demodulated signals; correlating unit for estimating a fading channel signal based on pilot channel signals; Doppler frequency estimating unit for estimating Doppler frequency of the fading channel signal to generate Doppler frequency estimated values; correlation length selection unit for selecting a correlation length of the pilot channel signals based on the Doppler frequency estimated values; a plurality of reference signal generation unit for generating reference signals based on output signals from the correlating unit; and a plurality of weight vector estimating unit for generating weight vectors based on the reference signals and the signals and for providing the weight vector to the digital beamforming networks.

Growing community of inventors

Daejeon, South Korea

Jae Joon Park