Samsung Electronics Co., Ltd.

Korea Advanced Institute of Science and Technology

The University of Texas System

Yonsei University

Eun-Seok Ko

Yung-Soo Kim

Eun-Yong Kim

Myeon-Kyun Cho

Tak-Ki Yu

In-Soo Hwang

Dae-Sik Hong

Yu-Seok Kim

Pan-Yuh Joo

June Moon

Dae-Eop Kang

Vahid Tarokh

Sang-min Lee

Young-Ky Kim

Chung-Ryul Chang

Joo-Hwan Chun

Hojae Lee

Sanghoon Lee

Jong-Hyung Kwun

Sung-soo Kim

Young-Ho Jung

Robert Wendell Heath, Jr

Chan-Byoung Chae

Yong-Hoon Lee

Keun-Chul Hwang

Sang-Min Lee

David Mazzarese

Eun-Young Kim

Chung-Yong Lee

Ju-Mi Lee

Myoung-Seok Kim

Won-Yong Shin

Woo-Seok Nam

Hyun-Jong Yang

You-Kyung Oh

Mi-Sun Yoon

Apparatuses and methods for transmitting and receiving signals in a mobile communication system are provided. A method for transmitting a signal by an evolved Node B (eNB) in a mobile communication system includes transmitting a same control channel signal to each of a plurality of Radio Units (RUs), and transmitting a different data channel signal to each of the plurality of RUs. A data channel signal transmitted to each of the plurality of RUs may be determined taking into account at least one of a location of a User Equipment (UE) that will receive the data channel signal, and load balancing.

Apparatus and method for transmitting and receiving signal in a mobile communication system

An apparatus and method for operating a Codebook Subset Pattern (CSP) of a Base Station (BS) in a Multiple Input Multiple Output (MIMO) system are provided. The method includes determining whether there is a CSP-updated BS among the BS and adjacent BSs, exchanging the updated CSP between cells if it is determined that there is a CSP-updated BS, and broadcasting the CSP of each cell acquired through the exchange thereby reducing an inter-cell interference in the MIMO system.

Apparatus and method for reducing inter-cell interference in multiple input multiple output system

According to one embodiment, a method of a base station configured to select a precoding mode in a mobile communication system. When channel estimate information is received from at least one terminal, the channel estimate information is collected, so that user grouping is performed according to one precoding scheme from among multiple precoding schemes. Individual user scheduling is performed according to each precoding scheme, so that a service candidate group set is generated. The selected precoding scheme is maximized according to a transmission capacity of a service candidate group set for each precoding scheme. Data is then transmitted to a determined candidate group set using the determined precoding scheme.

Method and apparatus for joint processing and precoding mode selection based on limited feedback in mobile communication system

An apparatus and method are provided for precoding by limited cooperation in a wireless communication system. A method of data precoding by a Base Station (BS) in a wireless communication system includes determining a Channel Quality Indicator (CQI) parameter indicating channel size information between the BS and a User Equipment (UE) served by the BS; transmitting the determined CQI parameter through a backhaul to a central unit; receiving, from the central unit, a weight factor based on a CQI parameter from each cell; and determining a precoding vector based on the weight factor. The weight factor represents a relative ratio of an inter-cell environment that is to be interfered by the BS.

Apparatus and method for precoding by limited cooperation in a wireless communication system

In a Multiple-Input Multiple-Output (MIMO) communication system, a serving evolved Node B (eNB) receives a channel covariance matrix of the serving eNB and a channel covariance matrix for a first neighbor eNB with the highest interference among neighbor eNBs, from a User Equipment (UE). Received signal power information is generated for each subband-beam pair. Interference signal power information is generated for each subband-beam pair for the first neighbor eNB. The generated interference signal power information is exchanged with the first neighbor eNB for each subband-beam pair. Beam coordination information indicating a use status of each beam in each subband is generated for the UE, using the interference signal power information of the first neighbor eNB. The generated beam coordination information is exchanged with the neighbor eNB. Scheduling is performed on the UE using the generated beam coordination information and the beam coordination information of the first neighbor eNB.

Method and apparatus for scheduling in multiple-input multiple-output communication system

A Mobile Station (MS) is operable to select a precoding matrix in a multi-antenna wireless communication system. The method includes receiving, from a serving Base Station (BS), information on a precoding matrix of which use is prohibited and a precoding matrix to be used by a neighbor BS, estimating an interference signal for the precoding matrix to be used by the neighbor BS, and selecting a precoding matrix to be used by the serving BS by considering the estimated interference signal from the remaining precoding matrixes except for the precoding matrix of which use is prohibited among precoding matrixes used by the serving BS.

Apparatus and method for selecting precoding matrix in multiple antenna wireless communication system

An apparatus and method for generating an effective Signal to Noise Ratio (SNR) per stream in a Multiple Input Multiple Output (MIMO) wireless communication system is disclosed. The apparatus includes a selector, a calculator, a generator, and a decider. The selector selects effective streams among whole streams. The calculator calculates a relative SNR rate between the effective streams. The generator generates an equation having as a solution an SNR of a first effective stream. The decider decides an SNR per effective stream using the solution of the equation and the relative SNR rate.

Apparatus and method for generating effective signal to noise ratio per stream in a multiple input multiple output wireless communication system

An apparatus and method for detecting signals based on a Lattice Reduction (LR) algorithm in a Multiple Input Multiple Output (MIMO) wireless communication system are provided. The apparatus includes a plurality of operators for determining soft-decision values for respective streams by performing a soft modulo operation on respective symbol values included in a Receive (Rx) signal block multiplied by a lattice transformation matrix T, a plurality of inner decoders for determining Log Likelihood Ratio (LLR) values of codewords according to coding schemes for the respective streams by decoding the soft-decision values for the respective streams according to identical decoding scheme, a passer for restoring the LLR values representing the codewords generated in a transmitting end using the LLR values, and a plurality of outer decoders for determining LLR values of Transmit (Tx) bitstreams for the respective streams by decoding the LLR values representing the codewords generated in the transmitting end for the respective streams according to decoding schemes for the respective streams.

Apparatus and method for detecting signal based on lattice reduction to support different coding scheme for each stream in multiple input multiple output wireless communication system

An apparatus and method for reducing pilot overhead in a multi-antenna system are provided. The method generates postcodes and pre-codes for streams used to transmit signals to at least two receivers. The method allocates a pilot signal to at least one of the streams, and allocates an additional pilot signal shared by at least one of the streams. The method precodes the pilot signal allocated to at least one of the streams, the additional pilot signal, and data to be transmitted to each of the receivers, based on the pre-code for each of the streams, prior to transmission.

Apparatus and method for transmitting pilot signal in wireless communication system

A method and apparatus for multi-cell calibration in a wireless communication system supporting cooperative Multiple Input Multiple Output (MIMO) are provided. Operations of a Base Station (BS) according to the method include transmitting a first message indicating a start of multi-cell sounding calibration to a reference Mobile Station (MS); estimating an uplink channel matrix of the reference MS using pilot symbols received from the reference MS; transmitting pilot symbols for enabling the reference MS to estimate a downlink channel matrix; when receiving downlink channel information of cooperative BSs from the reference MS, transmitting second messages comprising the downlink channel information to the cooperative BSs; and determining a multi-cell calibration matrix using the uplink channel matrix and the downlink channel information received from the reference MS.

Apparatus and method for calibration for cooperative multiple input multiple output in a wireless communication system

An apparatus and a method for beamforming in a wireless communication using a Base Station (BS) cooperative scheme are provided. The beamforming method includes exchanging channel status information with at least one cooperative BS which provides a BS cooperative service, generating a beamforming weight based on the channel status information, determining channel variation caused by a time delay in the channel status information exchange with the cooperative BS, updating the generated beamforming weight based on the channel variation, and precoding a transmit signal based on the updated beamforming weight.

Apparatus and method for reducing inter-cell interference in wireless communication system

An apparatus and method for pilot transmission in a wireless communication system are provided. The method includes generating a precode and a postcode for coordinated beamforming using channel information of one or more streams for transmitting signals to one or more receive ends, selecting one or more streams to be allocated pilots, updating the precode according to a reference point for representing an effective channel of non-selected streams orthogonal to an effective channel of the selected streams, and precoding signals transmitted through the streams.

Apparatus and method for pilot transmission in a wireless communication system

An apparatus and method for beamforming in a multi-antenna system are provided. The method includes assuming at least one codeword comprised in a codebook as a precoding weight of a reference receive end and generating post-processing weights of at least two receive ends, confirming a codeword maximizing a sum rate using the post-processing weights, generating preceding weights of the receive ends using the codeword maximizing the sum rate, and precoding a transmit signal using the generated precoding weights and transmitting the precoded transmit signal to each receive end.

Apparatus and method for beamforming in a multi-antenna system

A method and apparatus for selecting an antenna in a communication system is provided. The apparatus includes a mobile station for determining a set of transmit antennas by considering statistical channel information, for determining a subset of the transmit antennas, which can increase a diversity gain and reduce an effect of a spatial correlation, from among the determined set of the transmit antennas by considering the statistical channel information and instantaneous channel information, for generating antenna selection information by using the determined subset of the transmit antennas, and for feeding back the generated antenna selection information to a base station.

Growing community of inventors

Seongnam-si, South Korea

Eun-Seok Ko