Abstract: Quality of Service (QoS) switching method and apparatus in a mobile communication system are provided. The method includes determining, based on a total resource usage for providing a plurality of QoSs, the QoS switching relating to level adjustment of the plurality of QoSs corresponding to one of downgrade, upgrade, and grade maintenance, and adjusting levels of the plurality of QoSs according to the determined QoS switching.

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: Quality of Service (QoS) switching method and apparatus in a mobile communication system are provided. The method includes determining, based on a total resource usage for providing a plurality of QoSs, the QoS switching relating to level adjustment of the plurality of QoSs corresponding to one of downgrade, upgrade, and grade maintenance, and adjusting levels of the plurality of QoSs according to the determined QoS switching.

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: 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: 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 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.

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: 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 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: 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 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.

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 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: 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 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: 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.

Abstract: Disclosed is a method for supporting a handover in a broadband wireless access communication system which includes a mobile subscriber station, a serving base station currently providing service to the mobile subscriber station, and a plurality of adjacent base stations different from the serving base station, in which each of the base stations includes cells using subchannel bands different from each other, the method including establishing a set of base stations which currently provide wireless channels for data transmission/reception to the mobile subscriber station; classifying, by each base station, entire subchannels into a plurality of sets of subchannels; and allocating each of the sets of subchannels obtained by the classification to a PUSC (Partial Usage of Subchannels) subchannel area of each sector, wherein, every base stations included in an active set select an equal number of PUSC subchannels from among a PUSC subchannel area allocated to each of the base stations and allocate the selected PUSC