Electronics and Telecommunications Research Institute

Kt Corporation

Sk Telecom Company, Ltd.

Samsung Electronics Co., Ltd.

Ktfreetel Co., Ltd

Hye-Kyung Jwa

Seung-Chan Bang

Young-Hoon Kim

Il-Gyu Kim

Moon-Sik Lee

Kyung Hyun Park

Hyeong-Geun Park

Kap-Seok Chang

Hyoseok Yi

Nam-Il Kim

Hyung-Cheol Shin

Sang-Woo Nam

Eun-Jeong Shin

Duk-Hyun You

Mu-Yong Shin

Provided is a method of forming a random access preamble structure for an extended cell radius in a cellular system, the method including: generating a cyclic prefix (CP), which is the sum of a maximum delay spread and the maximum round trip delay according to the extended cell; generating a preamble sequence part. The method is used to form a preamble structure for an extended cell radius from among random access preamble structures transmitted when initial synchronization is achieved, when synchronization is lost, or when a handover is performed, during a random access process of the cellular system.

Random access preamble structure in extended cells environment

A method and apparatus for estimating a channel in a frequency domain are provided. The apparatus acquires frequency selectivity information using a cell-specific reference signal, selects a channel estimation scheme using a user specific reference signal according to the acquired frequency selectivity information, and estimates a frequency channel using the selected channel estimation scheme. Accordingly, more accurate channel estimation with respect to a region to which a physical downstream shared channel is allocated can be performed.

Apparatus and method for estimating channel in channel domain

The present invention relates to a packet data transmission method in an OFDMA system and an apparatus thereof. The present invention provides a user packet data transmission method including generating a RACH burst for channel information estimation, selecting a first antenna among a plurality of antennas, transmitting the RACH burst through the first antenna to a base station, receiving a data transmission acceptance signal from the base station, in response to the RACH burst, transmitting user packet data through the first antenna when receiving a signal indicating that the data transmission is allowed, and selecting a second antenna that is difference from the first antenna and transmitting a RACH burst through the second antenna when receiving a signal indicating that the data transmission is not allowed, and a transmitting apparatus of a mobile station having the plurality of antennas. According to the present invention, the RACH burst and user packet data are transmitted by using a mobile station having a plurality of antennas in an LTE-applied OFDMA system, and therefore data transmission can be performed with a wide bandwidth and high data rate and a deep fading period that may occur during the data transmission can be reduced, thereby preventing call dropping and improving data transmission performance.

Method and apparatus for transmitting by using transmit diversity at DFT spread OFDMA

The present invention provides an OFDM symbol generating apparatus. The OFDM symbol generating apparatus generates a plurality of weight-applied symbol groups by applying a plurality of weights to a digital modulation symbol group, and generates a plurality of IFFT symbol groups by performing an IFFT operation on the plurality of weight-applied symbol groups. Subsequently, an IFFT symbol group having the minimum PAPR is selected from among the plurality of IFFT symbol groups such that a characteristic of a PAPR can be improved without reducing data transmission speed.

Method and apparatus for generating and receiving OFDM symbol

An apparatus and method for detecting a space-time multi-user signal are disclosed. The apparatus includes: an RF/IF processing unit for converting received signals through an array antenna into digital baseband signals; a splitting unit for dividing the digital baseband signals into data signals and reference signals; a estimating unit for estimating a delay time information and a channel impulse response; a vector generating unit for receiving the reference signals and the delay time information of to thereby generate a beamforming weight vector; a matrix generating unit for receiving the channel impulse response and the beamforming weight vector to there by generate a system matrix; a filtering unit for receiving the data signals and the system matrix to multiply the system matrix to data per each antenna; a antenna combining unit for combining signals outputted from the filtering unit; and an interference cancelling unit for cancelling an interference signal.

Apparatus and method for detecting space-time multi-user signal of base station having array antenna

Disclosed is a transceiver for a base station with a smart antenna having a plurality of antennas. The transceiver comprises: a multipath searching unit for searching multipath delay information for each demodulation channel; a demodulating unit for forming an adaptive beam for each demodulation channel by using the multipath delay information for each demodulation channel for receiving signals and performing demodulation to the received signals and outputting at least one adaptive beam weight vector; a controlling unit for selecting at least one downlink beam index for each channel; and a modulating unit for selecting the downlink switched beams and forming switching beam for modulating signals of each channel and outputting the modulated signals in downlink.

Transceiver for a base station with smart antenna and a switched beamforming method in downlink

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Daejeon, South Korea

Hye-Kyung Jwa