Abstract: An apparatus and method for beamforming in a broadband wireless communication are provided. The apparatus includes a first calculator for determining a degradation factor to indicate a degradation degree of a target signal due to interference cancellation by using a target channel matrix and at least one interfering channel matrix, a second calculator for determining a new noise power value to be used to calculate a beamforming vector if the degradation factor is greater than or equal to a threshold, and for determining the beamforming vector by using the new noise power value, and a beamformer for performing beamforming on a signal transmitted/received with a target Mobile Station (MS) by using the beamforming vector.

Abstract: An apparatus and a method for selecting a transmission mode in a multi-antenna system are provided. The method includes checking a channel characteristic of a transmitting end using a signal received over at least two antennas; and determining a multi-antenna transmission mode according to the channel characteristic. Accordingly, the loss of the system capacity gain can be reduced and the capacity gain of the system can be increased.

Abstract: An apparatus and method for beamforming in a wireless communication system are provided. The base station apparatus includes a calculator, a plurality of formers, and a plurality of adders. The calculator calculates a beam coefficient considering interference to a neighbor sector to be applied to transmission signals to mobile stations. The plurality of formers performs beamforming for a transmission signal to each mobile station within a corresponding sector using the beam coefficient. The plurality of adders adds the sector-based beamformed signals each provided from the plurality of formers, on a per-transmission-antenna basis.

Abstract: Apparatus and method for calibration in a multi-antenna system are provided. The method includes setting at least two transmission paths connected to antennas, respectively, as reference transmission paths, when receiving compensation signals transmitted in the reference transmission paths in at least two reception paths connected to the antennas, respectively, determining a phase difference of the reception paths using the received compensation signals, and calibrating the reception paths using the phase difference of the reception paths.

Abstract: Provided are an apparatus and a method for removing an interference in a multiple antenna system. The apparatus includes a channel estimator, a covariance matrix generator, a weight calculator, and a beam forming unit. The channel estimator estimates a channel for a service cell and an interference channel for an adjacent cell using sounding signals via a plurality of antennas. The covariance matrix generator generates a covariance matrix as an average value from the interference channel. The weight calculator calculates a beam coefficient using the covariance matrix. The beam forming unit forms a beam using the beam coefficient.

Abstract: A method for controlling power in a communication system. The power control method in a base station includes receiving channel information from a plurality of mobile stations, and generating power control information of the mobile stations according to the received channel information; mapping the generated power control information to transmission fields of corresponding mobile stations according to allocation information of channels allocated to receive the channel information; and broadcasting to the mobile stations a message including the power control information mapped to the transmission fields of the corresponding mobile stations.

Abstract: A method for controlling power in a communication system. A base station allocates Channel Quality Information Channels (CQICHs) to at least one mobile station, transmits CQICH information for the allocated CQICHs, and transmits power control information to the mobile stations to which the CQICHs are allocated. A mobile station receives CQICH allocation information, receives power control information, and detects the power control information allocated to the mobile station by using the CQICH allocation information.

Abstract: A method for controlling power in a communication system. A base station allocates Channel Quality Information Channels to at least one mobile station, transmits the allocated Channel Quality Information Channel information, and transmits power control information to the mobile station to which the Channel Quality Information Channel is allocated. And a mobile station for receives Channel Quality Information Channel allocation information, receives power control information, and detects the power control information allocated to the mobile station by using the Channel Quality Information Channel allocation information.

Abstract: A calibration apparatus and method for controlling the phase and amplitude of a signal in a smart antenna multicarrier communication system are provided. A calibration signal is allocated to remaining carriers after allocating carriers to a data signal, prior to transmission. Thus, the efficiency of frequency resources for data transmission is increased.

Abstract: A method is provided for controlling an uplink traffic load in a wireless mobile communication system. A mobile station (MS) receives a reference signal from each of a base station (BS) of its home cell and a BS of a neighbor cell; calculates a power difference between the received reference signals to estimate a path loss value for each individual BS, and reports the estimated path loss value to the BS of the home cell. The BS of the home cell receives the estimated path loss value for each individual BS from the MS; and determines and allocates uplink traffic transmission power and a data rate to the MS taking the estimated path loss value into consideration. The MS transmits an uplink traffic signal taking into account the uplink traffic transmission power and the data rate allocated from the BS of the home cell.

Abstract: An apparatus and method for beamforming in a broadband wireless communication are provided. The apparatus includes a first calculator for determining a degradation factor to indicate a degradation degree of a target signal due to interference cancellation by using a target channel matrix and at least one interfering channel matrix, a second calculator for determining a new noise power value to be used to calculate a beamforming vector if the degradation factor is greater than or equal to a threshold, and for determining the beamforming vector by using the new noise power value, and a beamformer for performing beamforming on a signal transmitted/received with a target Mobile Station (MS) by using the beamforming vector.

Abstract: Provided are an apparatus and a method for removing an interference in a multiple antenna system. The apparatus includes a channel estimator, a covariance matrix generator, a weight calculator, and a beam forming unit. The channel estimator estimates a channel for a service cell and an interference channel for an adjacent cell using sounding signals via a plurality of antennas. The covariance matrix generator generates a covariance matrix as an average value from the interference channel. The weight calculator calculates a beam coefficient using the covariance matrix. The beam forming unit forms a beam using the beam coefficient.

Abstract: Apparatus and method for calibration in a multi-antenna system are provided. The method includes setting at least two transmission paths connected to antennas, respectively, as reference transmission paths, when receiving compensation signals transmitted in the reference transmission paths in at least two reception paths connected to the antennas, respectively, determining a phase difference of the reception paths using the received compensation signals, and calibrating the reception paths using the phase difference of the reception paths.

Abstract: An apparatus and method for controlling a digital AGC in a communication system in which power changes significantly from frame to frame. In the digital AGC controlling apparatus, an SNR estimator estimates an uplink SNR of a next frame. A power measurer measures uplink received power of every frame. A gain calculator estimates uplink power of an nth frame using an SNR estimate of an (n?1)th frame received from the SNR estimator and a received power measurement of the (n?1)th frame received from the power measurer, and calculates a gain to be applied to the nth frame in the digital AGC using the uplink power estimate of the nth frame.

Abstract: An apparatus and a method for interference cancellation in a wireless communication system are provided. The method includes receiving channel information from one or more terminals; classifying the terminals into terminals interfered by a neighbor cell and terminals not interfered by the neighbor cell based on the channel information of the terminals; and allocating the terminals interfered by the neighbor cell and the terminals not interfered by the neighbor cell into different resource regions. The transmitter forms the beam taking into consideration the neighbor-cell interference by acquiring the channel information of the neighbor-cell terminals interfered by the transmitter and the scheduled terminal information during beamforming.

Abstract: A method for controlling power in a communication system. A base station allocats Channel Quality Information Channels to at least one mobile station, transmits the allocated Channel Quality Information Channel information, and transmits power control information to the mobile station to which the Channel Quality Information Channel is allocated. And a mobile station for receives Channel Quality Information Channel allocation information, receives power control information, and detects the power control information allocated to the mobile station by using the Channel Quality Information Channel allocation information.

Abstract: A method for controlling power in a communication system. A base station allocates Channel Quality Information Channels (CQICHs) to at least one mobile station, transmits CQICH information for the allocated CQICHs, and transmits power control information to the mobile stations to which the CQICHs are allocated. A mobile station receives CQICH allocation information, receives power control information, and detects the power control information allocated to the mobile station by using the CQICH allocation information.

Abstract: An apparatus and method for beamforming in a wireless communication system are provided. The base station apparatus includes a calculator, a plurality of formers, and a plurality of adders. The calculator calculates a beam coefficient considering interference to a neighbor sector to be applied to transmission signals to mobile stations. The plurality of formers performs beamforming for a transmission signal to each mobile station within a corresponding sector using the beam coefficient. The plurality of adders adds the sector-based beamformed signals each provided from the plurality of formers, on a per-transmission-antenna basis.

Abstract: An apparatus and a method for selecting a transmission mode in a multi-antenna system are provided. The method includes checking a channel characteristic of a transmitting end using a signal received over at least two antennas; and determining a multi-antenna transmission mode according to the channel characteristic. Accordingly, the loss of the system capacity gain can be reduced and the capacity gain of the system can be increased.

Abstract: A method for controlling power in a communication system. The power control method in a base station includes receiving channel information from a plurality of mobile stations, and generating power control information of the mobile stations according to the received channel information; mapping the generated power control information to transmission fields of corresponding mobile stations according to allocation information of channels allocated to receive the channel information; and broadcasting to the mobile stations a message including the power control information mapped to the transmission fields of the corresponding mobile stations.