Samsung Electronics Co., Ltd.

Yonsei University

New Jersey Institute of Technology

Institute of Radio Engineering and Electronics of Ras

Ye-Hoon Lee

Dong-Ho Kim

Yeheskel Bar-Ness

Yung-Soo Kim

Yong-suk Kim

Myeon-Gyun Cho

Hak-Ju Lee

Seung-Hoon Nam

Jae-Hak Chung

Jong-Hyeuk Lee

Kwang-Soon Kim

Eung-sun Kim

Cheol-Woo You

Chung-Yong Lee

Dae-Sik Hong

Wan-Jin Kim

Keum-Chan Whang

Hyo-Yol Park

Seung-young Park

Woo-Kyung Lee

Ji-Won Kang

Jordi Diaz

Jae-Won Kang

Goo-Hyun Park

Guillem Malagarriga

Dmitriev Alexandre

Starkov Sergey

Guillem Ernest Malagarriga

Yeheskel Room 100 Faculty Building Bar-Ness

An apparatus is provided for transmitting a signal in a communication system. Upon receipt of an information vector, the apparatus includes converting the information vector into a plurality of sub-information vectors; performing coding and modulation on each of the sub-information vectors according to a corresponding mode thereby generating a modulation symbol; interleaving the modulation symbol generated for each of the sub-information vectors; allocating power to the interleaved modulation symbol for each individual mode; and beamforming the modulation symbols power-allocated for each individual mode, and transmitting the beamforming symbols.

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

A method is provided for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N&#xd7;M antennas. A transmitter splits a coded data stream into N sub-packets, and transmits the N sub-packets to a receiver via N transmission antennas. The receiver removes interferences of the N sub-packets received via M reception antennas, and independently decodes the interference-removed sub-packets. The receiver transmits an acknowledgement (ACK) or a negative acknowledgement (NACK) to the transmitter based on errors included in the decoded sub-packets. Upon receipt of the NACK, the transmitter retransmits to the receiver a sub-packet retransmission using ordering based on an Alamouti space-time coding scheme.

Method and apparatus for ordering retransmissions in an NxM MIMO system

A transmission method based on a Hybrid Automatic Repeat Request (HARQ) scheme for in a communication system. A codeword is generated using a Low Density Parity Check (LDPC) code. Parity bits of the codeword are classified on a basis of a transmission priority. Parity bits with an identical transmission priority are grouped. An information bit group of the codeword and parity bit groups with the identical transmission priority are shuffled in a predefined pattern. A packet is generated from the shuffled information bit group and the shuffled parity bit groups based on the transmission priority. The generated packet is retransmitted in response to a retransmission request. The transmission method can obtain the effect of channel interleaving by setting a transmission priority according to importance of puncturing target blocks, shuffling blocks with the same priority, and shuffling and transmitting bits configuring each block.

Low density parity check code-based hybrid automatic repeat request method

Practical transmission power adaptation in multicarrier code division multiple access (MC-CDMA) communications is using either a frequency domain technique or a time domain technique or a combined frequency and time domain technique in response to channel variations. With frequency domain power adaptation, the transmission power is allocated over the N' (1&#x2266;N&#x2032;&#x2266;N) strongest subcarriers rather than over all possible N subcarriers, where the strongest subcarriers are understood to exhibit the highest channel gains. A substantially optimal N&#x2032; can be chosen so that the average bit error rate (BER) is minimized. In the time domain power adaptation technique, transmission power is adapted so that the desired signal strength at the receiver output is maintained at a fixed level. In the combined time and frequency domain adaptation technique, the transmission power is first allocated over the N&#x2032; (1&#x2266;N&#x2032;&#x2266;N) strongest subcarriers rather than over all possible N subcarriers and then it is adapted so that the desired signal strength at the receiver output is maintained at a fixed level.

Combined frequency-time domain power adaptation for CDMA communication systems

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

Provided is a scheduling apparatus and method for allocating resources to individual users in a multiantenna system. The method includes determining a ratio of time slots to be allocated according to a ratio desired by each of the terminals in every specific time slot interval, calculating a channel capacity average and a standard deviation for each terminal according to channel capacity reported from each terminal for a specific time, and determining, based on the determined ratio of time slots, a terminal to which a specific time slot is to be allocated according to the channel capacity average and the standard deviation, calculated for each terminal, and the last reported channel capacity.

Apparatus and method for scheduling resources in a multiantenna system

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

A preamble generating method which includes computing (N) chaotic samples; transforming the (N) chaotic samples into (N) binary values of certain bits, respectively, and computing a chaotic sequence bit successively using the (N) binary values; and generating a preamble based on the chaotic sequence bit. By using the sequence bit from the chaotic samples, a plurality of preambles with optimum auto-correlation and cross-correlation properties is generated.

Method and apparatus for generating preamble using chaotic sequence

A method and apparatus for adaptively determining weights for transmission antennas according to a channel condition in a closed-loop transmit diversity system using a plurality of transmission antennas. The antenna weights are determined using variation of channel characteristics based on time and space, to thereby improve bit error rate performance. Parameters for fixing average transmission power per symbol according to the statistical channel characteristics for symbol energy and additive white Gaussian nose energy are previously determined to estimate channel characteristics. The antenna weights are determined using the parameters and channel gains estimated upon reception of data symbols.

Method and apparatus for determining antenna weight in a closed-loop transmit diversity system

A signal reception apparatus and method for communication systems. The signal reception apparatus for communication systems according to the present invention is applicable to communication environments in which a plurality of sub-bands having different frequency bands are sequentially used for communications. An embodiment of the invention has a multi-band index generation unit, a multi-band frequency generation unit, a multiplication unit, a correlation signal reception unit, and a buffer unit. The multi-band index generation unit generates a multi-band index corresponding to a sub-band to which a received signal is transmitted in correspondence with the multi-band index. The multiplication unit outputs a signal obtained by multiplying the received signal by the multi-band frequency. The correlation signal reception unit integrates and outputs the signal of the multiplication unit based on an integral time set in correspondence with the multi-band index. Further, the buffer unit buffers the signal of the correlation signal reception unit to be outputted at a predetermined data rate.

Signal reception apparatus and method for multi-band ultra-wideband communication systems

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Suwon-si, South Korea

Ye-Hoon Lee