Abstract: A method of scheduling data traffics at a base station in a wireless communication system is disclosed. The method includes preferentially assigning radio resources to a mobile station having a good channel state when the amount of data traffic generated is greater than a first threshold; preferentially assigning radio resources to a mobile station that has not been given radio resources for a long time when the amount of data traffic generated is less than the first threshold; and aggregating data traffic corresponding to the same Modulation and Coding Scheme (MCS) level to the same data traffic region and assigning radio resources to the data traffic when the amount of control information for data traffic assignment is greater than a second threshold.

Abstract: A system and method for power control in consideration of uplink channel quality information in a wireless communication system are disclosed. The method includes measuring first channel quality information from a signal received from a base station and transmitting the first channel quality information to the base station; receiving a power control message including a difference between an average channel quality value and a reference channel quality value from the base station, wherein the average channel quality value is obtained by averaging first and second channel quality information measured from a signal received by the base station, and the reference channel quality value is a reference required by the base station; and detecting the difference between the average channel quality value and the reference channel quality value and setting a transmission power for data communication using the difference.

Abstract: Disclosed is an apparatus for forming a downlink traffic beam in a base station that separately forms a traffic beam for each user using multiple antennas. In the apparatus, an instantaneous direction estimator detects a signal having maximum energy and an energy value from a received uplink signal. A downlink spatial correlation matrix update unit calculates a downlink spatial correlation matrix using an output value of the instantaneous direction estimator and a downlink antenna direction response characteristic. A beam vector adaptation unit outputs a downlink bean-forming vector by reflecting a phase difference between a common beam and a traffic beam from an output of the downlink spatial correlation matrix update unit.

Abstract: A method and apparatus is provided for transmitting/receiving a signal in a base transceiver station (BTS) of a communication system. The BTS compares power of a channel quality information (CQI) signal received from a terminal with power of a CQI signal for the terminal, received from a repeater, and performs a control operation so as to transmit a signal to be transmitted to the terminal directly to the terminal or transmit the signal to the terminal via the repeater according to the comparison result.

Abstract: An uplink scheduling apparatus and method in a communication system are provided. In the uplink scheduling method, a scheduling metric is calculated for each Mobile Station (MS). An MS with a high priority level is selected according to the calculated scheduling metric. The number of subchannels and a product of a modulation order and coding rate (MPR) are extracted according to input variables for the selected MS. The number of subchannels to be allocated to the selected MS is determined according to the MPR and the subchannels are allocated to the selected MS. The scheduling metric is updated for the each MS.

Abstract: A method is provided for uplink scheduling for a mobile station (MS) in a base station (BS) in a wireless mobile communication system in which the MS sends channel quality information to the BS. At least two logical regions are set to control transmission power of the MS and the number of sub-channels to be allocated to the MS according to an interference level at which a signal of the MS affects an adjacent cell/sector. The BS allocates the MS to a specific logical region while considering channel quality information of the MS. When the specific logical region is mapped to a set of MSs whose interference to the adjacent cell/sector is large, the BS limits the transmission power of the MS and the number of sub-channels to be allocated to the MS to predefined reference values or less.

Abstract: A transmitter and a transmitting method for forming a pseudo common beam using a plurality of antennas in a smart antenna communication system are provided, in which beams for tones of Orthogonal Frequency Division Multiplexing (OFDM) signals transmitted through a plurality of antennas are rotated at different phases around a frequency axis, such that a combined beam of the transmitted beams is equivalent to a pseudo common beam. Accordingly, a peak to average power ratio (PAPR) of the preamble signal is prevented from changing.

Abstract: A method is provided for transmitting data based on an Adaptive Modulation and Coding (AMC) technique in a Broadband Wireless Access (BWA) communication system. The method includes: measuring a channel quality information (CQI) difference for each of mobile stations (MSs) according to channel information fed back from the MSs; estimating a moving velocity of each of the MSs according to the CQI difference; selecting a mapping table for each individual MS taking into account the estimated velocity of each of the MSs, and allocating the selected mapping table; and transmitting data to a corresponding MS by applying a modulation scheme and a coding rate corresponding to the mapping table.

Abstract: An apparatus is provided for receiving channel quality information (CQI) in a mobile communication system in which a mobile station feeds back downlink CQI over a CQI transmission channel. In the apparatus, a power correlation estimator correlating code values mapped to tiles, wherein the CQI transmission channel includes a plurality of the tiles distinguished by time and frequency resources. A maximum detector detects CQI corresponding to a code value having the maximum power correlation value among estimated power correlation values. A threshold comparator compares the detected CQI with a CQI threshold, and outputs the detected CQI as final CQI if the detected CQI is greater than or equal to the threshold.

Abstract: A method and system for performing an inter-FA handover in a communication system are provided. An MS receives from a serving BS neighbor BS information including a BS ID of at least one neighbor BS and a reference signal index of a reference signal used in the at least one neighbor BS. When it is necessary to scan the reference signal from the at least one neighbor BS, the MS scans the reference signal corresponding to the reference signal index. If the scanned reference signal has a quality equal to or greater than a threshold, the MS determines the BS ID of the at least one neighbor BS using the reference signal index as a BS ID for a recommended neighbor BS available for the inter-FA handover.

Abstract: A system and method for transmitting control information and data to a mobile station in a communication system using adaptive antenna technology defined in a broadband wireless communication system. In a method for transmitting and receiving information data in the wireless communication system, a base station separates information data to be transmitted into control information and user data, applies different modulation and coding schemes to the control information and the user data, and transmits the information data to an associated mobile station. The mobile station identifies the modulation and coding schemes of the information data received from the base station and demodulates a total of the information data according to the modulation and coding schemes, or independently demodulates the control information and the data according to the modulation and coding schemes.

Abstract: An apparatus and method for transmitting/receiving channel quality information (CQI) in a communication system having a frame including subchannels corresponding to the same frequency reuse factor or different frequency reuse factors. A base station (BS) allocates at least one of the subchannels in the frame to a subscriber station (SS), and sends a transmission request for a CQI for a subchannel desired to be received, to the SS. The SS measures channel quality for individual subchannels requested by the BS in response to the CQI request, and transmits the measured channel quality to the BS.

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: In transmitting channel quality information (CQI) by a mobile station (MS) in a communication system, the mobile station receives from a base station (BS) information of an allocation of a CQI channel and information as to a modulation to be performed on the CQI. CQI channel signal is generated based on the CQI and the modulation information, where the CQI corresponds to a measured channel state. The CQI channel signal is transmitted to the BS over the allocated CQI channel.

Abstract: An apparatus and method for correcting phase and amplitude variations of a data signal caused by a non-linear system in a multi-antenna communication system. A BS adds a reference signal with a power level less than the power of the data signal to the data signal and accumulates the response of the non-linear system to the sum signal, estimates the variations in the phase and amplitude of the data signal, and calibrates the data signal using the estimate.

Abstract: A data rate determining method and apparatus in a smart-antenna mobile communication system are provided. A ratio of other-cell interference to AWGN in total noise received at an MS is estimated and a power margin is applied in proportion to highly time-variant other-cell interference. Therefore, despite a change in the other cell interference between a rate decision time and an actual data transmission time, a successful data transmission rate is increased.

Abstract: A method for controlling transmit power of a preamble sequence by a Subscriber Station in an Orthogonal Frequency Division Multiple Access communication system, the system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence.

Abstract: An apparatus and method for changing an uplink power control scheme according to mobile status in a TDD mobile communication system are provided. A subscriber station transmits to a base station a power control change request message including information about a requested power control scheme. Upon receipt of the power control change request message, the base station selects a power control scheme for the uplink of the subscriber station and transmits to the subscriber station a power control change command message including information about the selected power control scheme. The subscriber station extracts, upon receipt of the power control change command message from the base station, the power control scheme information from the power control change command message and selects a power control scheme according to the extracted information.

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: Disclosed is a method and an apparatus for generating a preamble sequence for an adaptive antenna system supporting a space division multiple access in an OFDMA communication system. Particularly, disclosed is a method for forming a preamble sequence identifying each of a plurality of mobile subscriber stations located within a cell or a sector of a communication system which includes a plurality of sub-channels assigned to the mobile subscriber stations, each of the sub-channels including a plurality of bins each of which includes n number of contiguous subcarriers in a frequency domain, the preamble sequence being transmitted before each of the sub-channels is transmitted, the method including the step of generating a preamble sequence by phase-shifting a predetermined sequence according to a predetermined phase shift sequence in the frequency domain.