Abstract: An apparatus is provided for transmitting uplink fast feedback information in a wireless communication system. In the apparatus, a channel encoder generates uplink fast feedback information to transmit, and outputs 3-bit codewords being set according to the fast feedback information. A noncoherent modulator modulates transmission symbols corresponding to the codewords using a noncoherent modulation scheme, and allocates the modulated transmission symbols to each of subcarrier bundles. An inverse fast Fourier transform (IFFT) unit IFFT-processes a transmission signal comprised of the subcarrier bundles before transmission.

Abstract: An apparatus and method for eliminating interference in a base station (BS) of a communication system. A first BS receives a first reception signal from a first mobile station located in a cell of the first base station. A second base station being adjacent to the first base station delivers decoding information of a second reception signal to the first base station, the second reception signal received from a second mobile station located in a cell of the second base station. The first BS determines whether an error exists on the second reception signal, based on the decoding information and re-generates an interference signal using the decoding information of the second reception signal when no error exists in the second reception signal, and performing interference elimination on the first reception signal using the re-generated interference signal.

Abstract: A method and apparatus for transmitting uplink acknowledge information (ACK) in a communication system using an orthogonal frequency division multiple access (OFDMA) scheme. The method includes receiving a data bit for the uplink ACK; outputting codewords corresponding to the data bit; performing quadrature phase shift keying (QPSK) modulation on symbols for ACK vector indexes corresponding to the codewords for the received data bit; performing inverse fast Fourier transform (IFFT) on a transmission signal having subcarrier clusters to which the modulated transmission symbols are allocated; and transmitting the IFFT-processed transmission signal.

Abstract: A space-time-frequency block coding apparatus and method in a transmitter with three transmit (Tx) antennas are provided. An input symbol sequence is transmitted through three Tx antennas according to a set method using feedback information received from a receiver or using a selected transmission matrix having regularities in order to improve the performance of an STFBC.

Abstract: A space-time-frequency block coding apparatus and method in a transmitter with three transmit (Tx) antennas are provided. An input symbol sequence is transmitted through three Tx antennas according to a permutation method using a selected transmission matrix in order to improve the performance of an STFBC.

Abstract: An apparatus and method for transmitting uplink fast feedback information using a fast feedback channel in an orthogonal frequency division multiple access (OFDMA) communication system. A channel encoder selects information data for uplink fast feedback information, and determines a codeword from a pre-determined codeword set corresponding to the selected information data. A non-coherent modulator chooses transmission symbols by performing orthogonal modulation according to the determined codeword based on a predetermined modulation pattern, and maps the chosen symbols into sub-carriers. An inverse fast Fourier transform (IFFT) block performs an inverse fast Fourier transform (IFFT) on the mapped symbols and transmits the IFFT processed mapped symbols.

Abstract: An apparatus and method for estimating a Signal to Interference plus Noise Ratio (SINR) in a wireless communication system are provided. The method includes processing a received signal by Orthogonal Frequency Division Multiplexing (OFDM) demodulation to convert the received signal into frequency-domain data, selecting ranging data from the frequency-domain data, multiplying the selected ranging data by a ranging code to perform code demodulation, calculating at least one norm value and at least one coherent norm value by bundle for the code-demodulated data and estimating an SINR using the calculated at least one norm value and at least one coherent norm value.

Abstract: A method and apparatus are provided for calculating a log-likelihood ratio (LLR) for decoding in a receiver for a mobile communication system, wherein the method and apparatus determine selection bits for distinguishing four quadrants in a constellation representing signal points of transmission symbols, determine domain bits for distinguishing the signal points in each domain of the four quadrants according to a modulation order of the transmission symbols, repeat an operation of dividing a received signal into a real component and an imaginary component according to the number of determined domain bits, calculate and origin-shift absolute values of the real component and the imaginary component, and calculate LLRs for the selection bits. Further, the method and apparatus can subsequently calculate LLRs for corresponding domain bits each time the origin-shifted received signal is received.

Abstract: An apparatus and method for full-diversity, full-rate space-time block coding in a transmitter using two Tx antennas are provided. An input symbol sequence is STBC-encoded in a predetermined method and transmitted through the two Tx antennas.

Abstract: An STFBC coding apparatus for a transmitter with four Tx antennas is provided. In the transmitter, an encoder generates a code symbol vector by encoding an input symbol sequence in a predetermined coding method. A grouping block permutes the elements of the code symbol vector by multiplying the code symbol vector by a permutation antenna grouping pattern selected among predetermined permutation antenna grouping patterns according to a predetermined order and outputs the permuted code symbol vector as a grouping symbol vector. OFDM (Orthogonal Frequency Division Multiplexing) modulators OFDM modulate the grouping symbol vectors and transmit OFDM modulated symbols through the four transmit antennas.

Abstract: An apparatus and a method for interference cancellation in a broadband wireless communication system are provided. A receiving apparatus includes an estimator, a channel compensator, and a demodulator. The estimator estimates channels of a desired signal and at least one interference signal, estimates noise, calculates a mean interference power of each interference signal, and calculates a mean noise power. The channel compensator channel-compensates burst data. The demodulator calculates a noise variance value by adding the mean noise power to the at least one mean interference power and creates Log Likelihood Ratio (LLR) by demodulating the channel-compensated data.

Abstract: An interference canceling apparatus and method in a broadband wireless communication system is provided. The method includes deriving a first channel estimate value of a desired signal and a first interference channel estimate value of an interference signal by using burst allocation information of selected sectors or cells; deriving a first noise estimate value using the first channel estimate values and the first interference channel estimate value; detecting an interference signal interfering the desired signal by using the first interference channel estimate value and the noise estimate value; deriving burst allocation information of the detected interference signal and the desired signal; and deriving a second channel estimate value of the desired signal and a second interference channel estimate value of the interference signal using the derived burst allocation information.

Abstract: A Channel estimating apparatus and method for use in a broadband wireless communication system are provided. The receiving method includes determining a control unit for a channel estimation using burst allocation information of selected sectors; extracting pilot symbols from received data based on the control unit; and acquiring a channel estimate value for each transmission unit by performing a Joint Channel Estimation (JCE) with the extracted pilot symbols that are based on the control unit.

Abstract: A method and apparatus for estimating noise in a signal reception apparatus of a communication system are provided. The method and apparatus include a channel estimator for estimating a channel for a signal vector received from multiple cells, and a noise estimator for estimating noise using the received signal vector, a number of the cells, a number of pilot subcarriers used for the channel estimation and pilot patterns used in the cells. As provided, the noise estimation method and apparatus improve decoding performance which improves cell capacity in a communication system.

Abstract: The present invention relates to a transmitter and a transmission method in communication system using three Tx antennas in order to maximize STFBC coding gain. An input symbol sequence is transmitted through a plurality of Tx antennas in a predetermined method.

Abstract: A device and method for measuring power of a received broadband signal including narrowband interference in a mobile communication system is provided. An interference eliminator removes the narrowband interference from the received broadband signal through a filter. A power compensator calculates a compensation value for compensating for at least one portion of the received signal removed when the narrowband interference was removed. A received power measurement unit measures power of the received signal received from the interference eliminator, and compensates for a measurement error in the measured power due to the removed at least one portion using the compensation value, and then outputs the received broadband signal having the compensated power.

Abstract: An apparatus and method for canceling narrow-band interference in a wideband mobile communication system. The apparatus includes a down converter for down converting a received signal into a baseband signal, an analog-to-digital converter for converting the baseband signal into a digital signal, a decimation filter for decimating the digital signal according to a decimation ratio, an interference canceller for detecting narrow-band interference signals contained in an output of the decimation filter, and canceling the narrow-band interference signals, and a demodulator for demodulating an output of the interference canceller.

Abstract: A space-time block coding (STBC) apparatus and method for a transmitter with four Tx antennas is provided. An input symbol sequence is transmitted through the four Tx antennas in a predetermined method based on feedback information received from a receiver, thereby improving the performance of an STBC.

Abstract: An apparatus and method for preventing power imbalance between antennas in a closed-loop MIMO system are provided. In a transmitter in the MIMO system, a first calculator generates a vector by multiplying a transmission vector by a beamforming matrix and a second calculator generates a plurality of antenna signals by multiplying the vector by a predetermined phase rotation matrix.

Abstract: An apparatus and method for selecting at least two users to be serviced in SDMA in an SDMA wireless communication system are provided. All users are ordered according to a predetermined rule and all possible user combinations each having at least two users are created from the ordered users. An investigation limit number is set using the capacity of a jth user combination. Or a total investigation number is reduced by comparing the interference-reflected SNR decrements of users with an investigation threshold. Therefore, the computation volume for selecting SDMA users is decreased.