Abstract: A Multiple Input Multiple Output (MIMO) wireless communication system is provided. A receiving end apparatus includes an estimator for estimating a channel between a plurality of Transmit (Tx) antennas of a transmitting end and a plurality of Receive (Rx) antennas of a receiving end; a filter for extracting a sum between interference and noise included in an Rx signal by using the estimated channel value and for computing a covariance matrix for the sum between the interference and the noise; and a detector for detecting a Tx signal by using a signal processing matrix generated from the covariance matrix.

Abstract: Provided is an apparatus and method for compensating a timing offset in a broadband wireless communication system. A receiving apparatus for the timing offset compensation includes a selector, a first calculator, and a second calculator. The selector groups two or more adjacent tiles into one or more tile groups and selects one or more pilot pairs, each including adjacent pilot signals, from each tile group. The first calculator calculates an average phase difference between the pilot pairs. The second calculator calculates a timing offset using the average phase difference.

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.

Abstract: A method and system for transmitting reference signals in a BWA communication system using a first transmit antenna, a second transmit antenna, and a plurality of sub-carriers. Each of the sub-carriers occupies a sub-frequency domain. In the method, reference signals for identifying a first transmit antenna are transmitted through a second predetermined number of sub-carriers in a first mini sub-channel transmitted through the first transmit antenna and occupied by a predetermined time domain and sub-frequency domains of a first predetermined number of sub-carriers, and reference signals for identifying a second transmit antenna are transmitted through the second predetermined number of the sub-carriers in a second mini sub-channel transmitted through the second transmit antenna and occupied by the time domain and the sub-frequency domains of the first predetermined number of sub-carriers.

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 transmitter for minimizing a PAPR in OFDM communication system. The transmitter includes: a precoder for coding input symbols so that a signal rotation is generated, and generating a complex vector including the coded symbols; an encoder for performing a frequency-space mapping for the symbols generated as the complex vector according to a predetermined scheme; a random mapper for randomly mapping the symbols for which the frequency-space mapping has been performed on a frequency plane through at least one transmit antenna; an Inverse Fast Fourier Transform (IFFT) unit for performing an IFFT for the symbols for which the frequency-space mapping has been performed; and a gradient algorithm unit for receiving IFFTed signals from the IFFT unit and reducing the PAPR.

Abstract: Disclosed is a method for using various multiple antenna schemes in a baseband wireless access system is provided. According to the method, a downlink MAP message is constructed in order to support various multiple antenna schemes based on a multiple-input multiple output (MIMO), which is one of the multiple antenna schemes, so that compatibility with exiting MIMO technology having no MIMO feedback can be achieved and overhead occurring in transmission of an MAP information element can be reduced. Further, it is possible to efficiently support spatial multiplexing technology capable of transmitting multiple layers having different modulation and coding in a MIMO system.

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: 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 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: A Multiple Input Multiple Output (MIMO) wireless communication system is provided. A receiving end apparatus includes an estimator for estimating a channel between a plurality of Transmit (Tx) antennas of a transmitting end and a plurality of Receive (Rx) antennas of a receiving end; a filter for extracting a sum between interference and noise included in an Rx signal by using the estimated channel value and for computing a covariance matrix for the sum between the interference and the noise; and a detector for detecting a Tx signal by using a signal processing matrix generated from the covariance matrix.

Abstract: Provided is an apparatus and method for compensating a timing offset in a broadband wireless communication system. A receiving apparatus for the timing offset compensation includes a selector, a first calculator, and a second calculator. The selector groups two or more adjacent tiles into one or more tile groups and selects one or more pilot pairs, each including adjacent pilot signals, from each tile group. The first calculator calculates an average phase difference between the pilot pairs. The second calculator calculates a timing offset using the average phase difference.

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 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.

Abstract: A method of mapping Space-Time Coding (STC) data to subcarriers in a broadband wireless communication system using multiple antennas is provided. Transmission symbols are encoded according to a predetermined space-time coding matrix and the coded data symbols are mapped to time-space-subcarriers according to a mapping rule determined by the space-time coding matrix.

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.