Samsung Electronics Co., Ltd.

Yonsei University

Korea Advanced Institute of Science and Technology

Industry-Academic Cooperation Foundation

Myeon-Gyun Cho

Yung-Soo Kim

Dae-Hyun Kim

Keum-Chan Whang

Ye-Hoon Lee

Hyung-Myung Kim

Woo-Geun Ahn

Tae-Sung Kang

Jae-Won Kang

Sung-Jin Kim

Jong-Hyung Kwun

Sang-min Lee

Ho-Jin Kim

Se-Ho Kim

Sun-young Lee

Dong-Ho Kim

Jong-Hyeuk Lee

Kwang-Soon Kim

Eung-sun Kim

Daesik Hong

Dae-Sik Hong

Yu-Seok Kim

Dae-Young Park

Hyo-Yol Park

Goo-Hyun Park

A method for transmitting a signal in a wireless communication system. The method comprises the steps of: grouping two subcarriers having different channel characteristics; identifying a number of all cases occurring when either equal symbols or different symbols, among symbols determined upon applying a first modulation scheme, are mapped to the two subcarriers; and mapping two subcarriers corresponding to each of the number of all cases to one symbol according to a second modulation scheme, and transmitting the signal, wherein a modulation order of the second modulation scheme is two times higher than a modulation order of the second modulation.

Method for transmitting signal in wireless communication system

A method and system for allocating a channel are provided in a communication system including a plurality of Mobile Stations (MSs) and Base Stations (BSs) for providing a communication service to the plurality of MSs. A BS transmits an average Channel Quality Information (CQI) request to MSs. The MSs measure CQI with respect to their channels in response to the request from the BS, compute average CQI from the measured CQI, and transmit the average CQI to the BS. The BS selects a predefined number of MSs according to the average CQI received from the MSs and sets an MS group. The BS transmits a CQI request to the MS group. The MSs of the MS group transmit the CQI to the BS. The BS receives the CQI from the MS group and allocates a channel according to the CQI.

System and method for allocating a channel in a communication system

A method is provided a method for transmitting data in a MIMO communication system. The method includes receiving feedback information including channel quality information of transmission antennas from terminals; selecting one of a multi-user mode and a single user mode according to the channel quality information; extracting information for the selected mode from the feedback information; selecting at least one terminal and a preceding matrix of at least one transmission antenna through which data is transmitted according to the extracted information and the selected mode; and transmitting data using the selected precoding matrix and information of the selected terminal.

Method for transmitting data in a communication system

A method for allocating a sub-channel in a wireless communication system is disclosed. The method includes measuring a moving velocity of each of mobile stations (MSs); selecting MSs to which a sub-channel is to be allocated; determining a resource allocation period for sub-channel allocation to the MSs using the measured moving velocity; calculating an average amount of data to be transmitted for the determined resource allocation period, and sending a channel quality information (CQI) request to the MSs; upon receipt of CQI in response to the CQI request, allocating a sub-channel satisfying the average data amount taking the CQI into account; and transmitting a control signal for the sub-channel allocation to the MSs.

Apparatus and method for allocating sub-channel in a wireless communication system

A method for puncturing a Low Density Parity Check (LDPC). The method includes a) setting a codeword length and the total number of bit nodes to be punctured; b) selecting a check node (or check nodes) with highest priority excluding check nodes completely checked in a current round; c) selecting a bit node (or bit nodes) with a highest priority excluding bit nodes completely checked among bit nodes connected to the selected check node (or check nodes); d) determining whether the selected bit node is a bit node to be punctured, that is, it is not systematic, not set by a puncturing prohibition flag; e) puncturing an associated bit node if the selected bit node is the bit node to be punctured, setting unpunctured bit nodes connected to the selected check node by a puncturing prohibition flag, decreasing the number of remained bit nodes to be punctured by 1 and increasing the number of connected punctured node of associated check node by 1; f) determining whether the number of remaining bits to be punctured is greater than 0; and g) returning to step b) if the number of remaining bits to be punctured is greater than 0, and ending a puncturing process if the number of remaining bits to be punctured is not greater than 0.

Method for puncturing a low density parity check code

Disclosed is a method for estimating the velocity of a mobile station in Rician fading environments in which a direct wave exists. Cellular mobile communication environments include two environments, Rician fading environments in which a direct wave exists and Rayleigh fading environments in which a direct wave does not exist. Generally, many methods for estimating the velocity of a mobile station have been known in Rayleigh fading environments. However, in Rician fading environments in which a direct wave exists, many errors occurs in estimating the velocity of a mobile station due to difficulty in estimation of a Rician coefficient K and an incident angle &#x3b8;. According to the invention, a method is provided wherein error is mostly eliminated in estimating the velocity of a mobile station by obtaining a maximum Doppler frequency of the mobile station, even without directly obtaining a Rician coefficient K and an incident angle &#x3b8;.

Velocity estimation apparatus in mobile communication environments

Disclosed is a velocity estimator using a level crossing rate. The velocity estimator comprises a power calculator for calculating power values of a signal received from a mobile terminal; a mean power calculator for calculating mean power values for M power values according to a predetermined down-sampling factor M; an interpolator for interpolating the mean power values according to a predetermined interpolation ratio L; a root mean square calculator for calculating a root mean square value using an output of the interpolator; a level crossing counter for counting a level crossing frequency representing how many times the output of the interpolator crosses a level crossing threshold determined according to the root mean square value, for a predetermined time period; and a velocity calculator for calculating a velocity estimation value of the mobile terminal using the level crossing frequency.

Velocity estimation apparatus and method using level crossing rate

Growing community of inventors

Seongnam-si, South Korea

Myeon-Gyun Cho