Patent application number | Description | Published |
20080247478 | Orthogonal frequency division multiplexing communication system, multi-hop system, relay station, and spatially layered transmission mode - An apparatus and method for data transmission in an Orthogonal Frequency Division Multiplexing (OFDM) communication system are provided. An OFDM system includes a reference Relay Station (RS) and a cooperative relay station respectively for performing an Spatially Layered transmission Mode (SLM) process by modulating a phase and magnitude of a signal by using a predetermined modulation order suitable for the reference relay station to obtain a spatially-layered signal and for delivering the spatially-layered signal to a target Mobile Station (MS); a Base Station (BS) for selecting the reference relay station and the cooperative relay station among a plurality of relay stations; and an mobile station for detecting data through Maximum Likelihood (ML) detection in which a signal having the largest ML is detected by comparing the received spatially-layered signal with a signal which is converted through the SLM upon receiving the spatially-layered signal from the reference relay station and the cooperative relay station. | 10-09-2008 |
20080248803 | APPARATUS AND METHOD FOR ALLOCATING FREQUENCY RESOURCE IN A COMMUNICATION SYSTEM - A method and apparatus for allocating resources for a mobile station in a communication system is provided. The method includes determining if a mobile station within a cell is located in one of a first region corresponding to a cell center, a third region corresponding to a cell edge, and a second region corresponding to an area between the first and third regions, allocating frequency resources within an entire frequency band to the mobile station when the mobile station is located in the first region, wherein the entire frequency band comprises at least a first frequency band and a second frequency band, allocating frequency resources within the first frequency band to the mobile station when the mobile station is located in the third region, and allocating frequency resources within the second frequency band to the mobile station when the mobile station is located in the second region. | 10-09-2008 |
20080285673 | Apparatus and method for reducing peak to average power ratio based on tile structure in broadband wireless communication system - A broadband wireless communication system is provided. A transmitting end of the broadband wireless communication system includes: a controller for receiving a plurality of Orthogonal Frequency Division Multiple Access (OFDMA) symbols, and for generating the same number of symbol sets corresponding to the OFDMA symbols wherein each symbol set includes a plurality of OFDMA symbols having various Peak to Average Power Ratios (PAPRs) according to several phase-shifting patterns, a selector for grouping the plurality of OFDMA symbols into symbol groups according to the same phase-shifting pattern of the several phase-shifting patterns, and for finding maximum peak value in each symbol group, and a transmitter for transmitting the symbol group having a minimum value selected from among the maximum peak values of the symbol groups. | 11-20-2008 |
20090086848 | Apparatus and method for reducing peak-to-average power ratio in a wireless communication system - An apparatus is provided for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas. A symbol generator generates symbols to be transmitted via the multiple transmit antennas, and a PAPR calculator calculates a PAPR value for each symbol. A detector detects a maximum PAPR value among the PAPR values of the symbols. A controller outputs a control signal to reduce a PAPR value of a corresponding symbol when the detected maximum PAPR value exceeds a reference PAPR value. A PAPR reducer reduces the PAPR value of the corresponding symbol upon receipt of the control signal. | 04-02-2009 |
20090113271 | Method and apparatus for parallel structured latin square interleaving in communication system - A method and apparatus for parallel structured Latin square interleaving in a communication system are provided. The method includes dividing input information bits into sub-blocks according to a parallel processing order, generating a first Latin square matrix or a second Latin square matrix by comparing the parallel processing order with a predetermined threshold, and interleaving by reading out the information bits divided into the sub-blocks according to the generated Latin square matrix. | 04-30-2009 |
20090252246 | Receiving apparatus and method for maximum likelihood in a single carrier system - A receiving apparatus and method of a Maximum Likelihood (ML) scheme in a Single-Carrier (SC) system are provided. The apparatus includes at least two antennas, at least two Orthogonal Frequency Division Multiplexing (OFDM) demodulators, at least two subcarrier mappers, at least two OFDM modulators, and a detector. The antennas receive signals. The OFDM demodulators convert the signals into frequency domain signals. The subcarrier mappers confirm signals mapped to frequency domain subcarriers. The OFDM modulators convert the signals into time domain signals. The detector constructs at least one set for candidate transmission symbols and detects receive signals through ML detection using the set. | 10-08-2009 |
20100232531 | Optimum perturbation apparatus and method in a multi-antenna multi-user communication system - An optimum perturbation apparatus and method in a multi-antenna, multi-user communication system are provided. In the optimum perturbation method, upon receipt of modulation symbols, channel responses are decomposed into eigenvalues and eigenvectors by Single Value Decompositin (SVD) and a distortion value of the modulation symbols is estimated using the eigenvectors and the eigenvalues to minimize noise and interference power. The modulation symbols are precoded by combining the modulation symbols with the estimated distortion value. | 09-16-2010 |
20120020425 | APPARATUS AND METHOD FOR MINIMIZING ERRORS BY A CELL EDGE USER IN A MULTI-CELL COMMUNICATION SYSTEM - The present invention relates to performance improvement in a cell edge, particularly, to a method for selecting a precoder for a terminal in a multiple antenna system, wherein the method comprises: performing channel estimation for reference signals of a serving base station and another base station; determining a minimum singular value by using the channel estimation result; and if a complete collaborative feedback structure is used, feeding back a table of the determined, minimum singular value to the base stations. | 01-26-2012 |
20120057623 | APPARATUS AND METHOD FOR POWER CONTROL IN BROADBAND WIRELESS ACCESS SYSTEM - Uplink power control in a broadband wireless access system is provided. A Base Station (BS) includes a controller, a first generator, a second generator, and a modulator/demodulator (modem). The controller determines to apply one of a first power control which is slot-periodic and a second power control which is frame-periodic. The first generator generates a first power control command at a slot period using a channel quality premising a rake receiver according to the first power control. The second generator generates a second power control command at a frame period using a channel quality premising an equalizer according to the second power control, and generates a third power control command according to a predefined pattern at a slot not being able to use the channel quality. The modem transmits at least one of the first, second, and third power control commands. | 03-08-2012 |