Patent application number | Description | Published |
20080240304 | APPARATUS AND METHOD FOR INTERFERENCE CANCELLATION IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - 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. | 10-02-2008 |
20080240308 | APPARATUS AND METHOD FOR ESTIMATING CHANNEL USING SLIDING WINDOWS IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - An apparatus and a method for estimating a channel using sliding windows in a broadband wireless communication system are provided. The apparatus includes an estimator, a first calculator, a second calculator, and a third calculator. The estimator estimates a speed of travel. The first calculator calculates a time correlation values using the estimated speed. The second calculator calculates weight factors using the time correlation values. The third calculator calculates a channel estimation value by multiplying corresponding pilot symbols by the weight factors and equalizing the pilot symbols. | 10-02-2008 |
20100075594 | APPARATUS AND METHOD FOR CALIBRATION FOR RELAY STATION IN MULTIPLE ANTENNA COMMUNICATION SYSTEM - A calibration apparatus and method for supporting a Relay Station (RS) in a multiple antenna communication system are provided. The calibration method in the multiple antenna communication system which supports the RS includes, when a modem stage sends a downlink calibration signal, receiving, at a calibrator, the downlink calibration signal and estimating a downlink path channel, when the calibrator sends an uplink calibration signal, receiving, at the modem stage, the uplink calibration signal and estimating an uplink path channel, determining, at the modem stage, calibration coefficients per path not to generate a phase and amplitude difference with respect to the estimated uplink path channel and the estimated downlink path channel, and applying the calibration coefficients per path to corresponding antennas respectively. | 03-25-2010 |
20100210227 | APPARATUS AND METHOD FOR SUPPORTING MULTIPLE-INPUT MULTIPLE-OUTPUT AND BEAMFORMING SIMULTANEOUSLY IN WIRELESS COMMUNICATION SYSTEM - An apparatus and a method for simultaneously supporting Multiple-Input Multiple-Output (MIMO) and beamforming in a wireless communication system are provided. In the method, two data streams are mapped to each of all of 2N transmission antennas; the two data streams are multiplied by different Cyclic Delay Diversity (CDD) phase sequences; the two data streams multiplied by the different CDD phase sequences for each transmission antenna are added; and the added data stream is multiplied by a beamforming coefficient and transmitted for each transmission antenna. | 08-19-2010 |
20100215088 | Apparatus and method for changing communication mode in multi-antenna system considering channel environment - An apparatus and a method for determining a multi-antenna transmission mode at a base station in a multi-antenna system are provided. The method for determining the multi-antenna transmission mode includes when using a Multiple Input Multiple Output (MIMO) transmission mode as a multi-antenna transmission mode, determining a reference set point; updating a set point for transmit power control of a terminal according to an error occurrence of a signal received from the terminal; determining whether a channel to the terminal is a channel for applying the MIMO transmission mode by comparing the updated set point with the reference set point; and when the channel to the terminal is not a channel for applying the MIMO transmission mode, changing the multi-antenna transmission mode to a fixed transmission mode. | 08-26-2010 |
20110141935 | METHOD AND APPARATUS FOR RECEIVING MINIMUM MEAN-SQUARED-ERROR IN SINGLE-CARRIER FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM - A method and an apparatus for receiving a Minimum Mean-Squared-Error (MMSE) in a Single-Carrier Frequency Division Multiple Access (SC-FDMA) system is provided. The method includes, transforming a signal in a time domain received through an antenna into a signal in a frequency domain, and discriminating between bands respectively allocated to terminals in a frequency domain, estimating a channel and computing a weight value from the signal transformed into the frequency domain, and detecting an MMSE, computing a time-domain bias from the weight value and a channel estimation value of the signal transformed into the frequency domain, normalizing the detected MMSE by using the computed time-domain bias, and transforming the normalized signal into a normalized signal in a time domain, decoding the normalized signal transformed to the time domain, and transmitting the decoded normalized signal transformed into the time domain to each of the terminals. | 06-16-2011 |
20110151802 | APPARATUS AND METHOD FOR ESTIMATING CHANNEL IN MOBILE COMMUNICATION SYSTEM - An apparatus and a method for estimating a channel in a mobile communication system are provided. The apparatus includes a channel estimation unit for determining a channel estimation value using a channel power for each of a plurality of fingers, and a noise estimation unit for selecting a scheme for estimating a thermal noise power according to a channel environment among schemes for determining a plurality of thermal noise powers, and for estimating a noise using the channel estimation value in the selected scheme. | 06-23-2011 |
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 |
20120113973 | METHOD AND APPARATUS FOR PIC CHANNEL ESTIMATOR CONSIDERING WEIGHT - A method and an apparatus apply an adaptive weight in a wireless communication system. In the method, channel estimation is performed. A weighting factor that reduces a Mean Square Error (MSE) is determined with respect to a channel in a specific section. A channel estimate value is multiplied by the weighting factor. | 05-10-2012 |