Abstract: 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.

Abstract: Provided are an apparatus and method for receiving a multipath signal in a wireless communication system. The apparatus includes a weighting block for receiving an estimated channel gain value output from a channel estimator and outputting an estimated weighted channel gain value and a compensator unit for receiving the estimated weighted channel gain value, reflecting the weight, and compensating, for an estimated channel gain.

Abstract: A method of generating a signal having a converted sampling rate in a communication system is provided. The method includes selecting effective input samples among S number of input samples included in an input stream corresponding to an input sampling rate, generating a filter coefficient set including filter coefficients having a length of a second tap, the filter coefficients having the length of the second tap being generated by dividing a filter coefficient having a length of a first tap configuring a low-pass filter into the filter coefficients having the length of the second tap corresponding to a number of selected effective input samples, selecting filter coefficients corresponding to each of the effective input samples among the filter coefficients included in the filter coefficient set, and outputting output samples having an output sampling rate which is converted from the input sampling rate.

Abstract: An apparatus and method for controlling a whitening function of a whitening Maximum Ratio Combining (MRC) in a receive end of a multiple antenna system are provided. The method includes identifying if there is interference from at least one neighbor cell, if there is interference, generating a weight of the whitening MRC using a pre-whitening inverse matrix, and, if there is no interference, generating a weight of the whitening MRC using a unit matrix, thus being capable of improving a reception performance of the receive end.

Abstract: 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.

Abstract: A method for measuring channel quality of a Base Station (BS) by using a ranging signal in a broadband wireless communication system is provided. The method includes estimating a time offset of the ranging signal received through a ranging channel, measuring channel quality by using the ranging signal including the time offset, determining whether distortion occurs in the measured channel quality by using the time offset, and compensating for distortion of the measured channel quality.

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: Method of estimating a channel in a wireless communication system by obtaining a channel impulse response from a pilot signal included in a received signal; estimating a timing offset with a maximum peak power value for the channel impulse response; and performing a phase compensation using the estimated timing offset and estimating a channel which is applied with the compensated phase.

Abstract: Provided are an apparatus and method for receiving a multipath signal in a wireless communication system. The apparatus includes a weighting block for receiving an estimated channel gain value output from a channel estimator and outputting an estimated weighted channel gain value and a compensator unit for receiving the estimated weighted channel gain value, reflecting the weight, and compensating, for an estimated channel gain.

Abstract: 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.

Abstract: A cyclic delay diversity (CDD) technique in a multiple-antenna broadband wireless communication system is provided. An apparatus in the multiple-antenna broadband wireless communication system includes: a controller for selecting at least one sub-carrier to which CDD is applied; at least one shifter for shifting a phase of a signal mapped to the at least one selected sub-carrier; and an operator for converting the signal, which is mapped to the at least one selected sub-carrier and whose phase is shifted, and other signals mapped to the remaining sub-carriers into time-domain signals.

Abstract: 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.

Abstract: A base station is capable of performing a method for velocity estimation in a mobile communication system. In the velocity estimation method, a received signal is delayed by a plurality of different sample intervals. A candidate maximum Doppler frequency for each of the delayed received signals is estimated. A maximum Doppler frequency in a reliable period is selected among the candidate maximum Doppler frequencies.

Abstract: An apparatus and method for rate control in a wireless communication system are provided. The apparatus includes a preprocessor, a rate controller, a determiner, and a transmitter. The preprocessor determines feedback information on a physical layer packet using a feedback message of MAC ARQ. The rate controller updates a CQI reported from a receiver using the determined feedback information. The determiner determines an MCS using the updated CQI. The transmitter transmits data using the determined MCS.

Abstract: An apparatus and method for controlling a whitening function of a whitening Maximum Ratio Combining (MRC) in a receive end of a multiple antenna system are provided. The method includes identifying if there is interference from at least one neighbor cell, if there is interference, generating a weight of the whitening MRC using a pre-whitening inverse matrix, and, if there is no interference, generating a weight of the whitening MRC using a unit matrix, thus being capable of improving a reception performance of the receive end.

Abstract: 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.

Abstract: A cyclic delay diversity (CDD) technique in a multiple-antenna broadband wireless communication system is provided. An apparatus in the multiple-antenna broadband wireless communication system includes: a controller for selecting at least one sub-carrier to which CDD is applied; at least one shifter for shifting a phase of a signal mapped to the at least one selected sub-carrier; and an operator for converting the signal, which is mapped to the at least one selected sub-carrier and whose phase is shifted, and other signals mapped to the remaining sub-carriers into time-domain signals.

Abstract: An apparatus and method for power allocation in a mobile communication system are provided. A transmitting method includes allocating a certain fraction of total power to a common control channel; allocating available power corresponding to the remaining fraction of the total power to remaining control channels except for the common control channel among control channels transmitted in a current time slot by considering the remaining control channels; calculating a gain value of each control channel according to power allocated to each control channel; and regulating a gain of each control channel, which is to be transmitted to one or more Access Terminals (ATs), according to the calculated gain value. Therefore, reception throughput of each control channel can be improved.

Abstract: A method is provided for estimating a Noise and Interference (NI) power in a ranging code reception apparatus in a communication system. The method includes generating S correlation values by calculating correlations between L ranging subcarriers received at a ranging code reception apparatus and L elements included in each of S ranging codes available in the ranging code reception apparatus, detecting N reception-desired ranging codes that the ranging code reception apparatus desires to receive, among the S ranging codes, using the S correlation values, and selecting M remaining ranging codes among (S-N) ranging codes obtained by removing the N reception-desired ranging codes from the S ranging codes, and estimating a first NI power using correlation values for the M remaining ranging codes.

Abstract: A method of generating a signal having a converted sampling rate in a communication system is provided. The method includes selecting effective input samples among S number of input samples included in an input stream corresponding to an input sampling rate, generating a filter coefficient set including filter coefficients having a length of a second tap, the filter coefficients having the length of the second tap being generated by dividing a filter coefficient having a length of a first tap configuring a low-pass filter into the filter coefficients having the length of the second tap corresponding to a number of selected effective input samples, selecting filter coefficients corresponding to each of the effective input samples among the filter coefficients included in the filter coefficient set, and outputting output samples having an output sampling rate which is converted from the input sampling rate.