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 interference canceling apparatus and method in a broadband wireless communication system is provided. The method includes deriving a first channel estimate value of a desired signal and a first interference channel estimate value of an interference signal by using burst allocation information of selected sectors or cells; deriving a first noise estimate value using the first channel estimate values and the first interference channel estimate value; detecting an interference signal interfering the desired signal by using the first interference channel estimate value and the noise estimate value; deriving burst allocation information of the detected interference signal and the desired signal; and deriving a second channel estimate value of the desired signal and a second interference channel estimate value of the interference signal using the derived burst allocation information.

Abstract: A method for scheduling data in a communication system having a downlink frame structure including power control regions of a boosting region for boosting power of a data burst, a normal region for keeping power of the data burst, and a deboosting region for deboosting power of the data burst.

Abstract: An apparatus and method for reducing the volume of a resource allocation information message in a broadband wireless communication system are provided, in which a scheduler determines whether to generate uplink control region allocation information, and a generator generates the uplink control region allocation information according to a result of the determination.

Abstract: An uplink (UL) power control apparatus and method in a broadband wireless communication system are provided. The Mobile Station (MS) includes a power controller for calculating a power compensation value using a last transmit power in a previous closed loop power control when a power control mode is changed to an open loop power control, and determining a transmit power according to the open loop power control using the power compensation value; and a transmitter for adjusting and transmitting the transmit power of a UL signal under control of the power controller.

Abstract: An apparatus and method for detecting a feedback signal in a multi-cell or multi-sector sector BS in a broadband wireless communication system are provided. A demodulator correlates each tile being sets of subcarriers carrying feedback information received from a serving sector/cell with each possible codeword and calculates the squares of the absolute values of the correlations of the tiles for each possible codeword. A first detection decider sums the squares for each possible codeword and determines whether to perform detection on the received feedback information. If it is impossible to detect the feedback information, a second detection decider receives feedback information from a target sector/cell, combines the feedback information received from the serving sector/cell and the target sector/cell, and determines whether to detect the combined feedback information.

Abstract: An apparatus and method for determining feedback information detection in a broadband wireless communication system are provided. In the detection determining apparatus, a demodulator correlates each of tiles carrying received feedback information with an orthogonal vector including a pilot symbol in each possible codeword, each tile being a predetermined number of subcarriers, and calculates the squares of the absolute values of the correlations. A codeword correlation calculator sums the squares of the absolute value of the correlations of the tiles for each possible codeword. A detection decider determines whether to perform detection on the feedback information based on the maximum of the sums.

Abstract: Disclosed is a method for detecting a user in a communication system. The method includes selecting i ranging sub-carrier signals among k sub-carrier signals upon which a k-point fast Fourier transform (FFT), has been performed multiplying the i ranging sub-carrier signals by a ranging code, performing k-point inverse fast Fourier transform (IFFT) on the i ranging sub-carrier signals multiplied by the ranging code, and (k-i) 0s, detecting a power of each of the IFFT-processed k point signals, estimating a power of a desired received signal and a power of an interference signal by using powers of the k point signals according to a predetermined scheme, and detecting a user depending on the power of the desired received signal and the power of the interference signal.

Abstract: An apparatus and method for selecting at least two users to be serviced in SDMA in an SDMA wireless communication system are provided. All users are ordered according to a predetermined rule and all possible user combinations each having at least two users are created from the ordered users. An investigation limit number is set using the capacity of a jth user combination. Or a total investigation number is reduced by comparing the interference-reflected SNR decrements of users with an investigation threshold. Therefore, the computation volume for selecting SDMA users is decreased.

Abstract: A TDM (Time Division Multiplexing)-based mobile communication system that switches a service type according to QoS (Quality of Service). The mobile communication system includes a base transceiver system (BTS) and a mobile station (MS) connected to the BTS. The BTS monitors whether a first service provided from the BTS to the MS is satisfied according to whether at least as much data as a predetermined transmission amount is transmitted to the MS. If the first service is dissatisfied, the BTS switches a service to a second service lower in QoS than the first service so that as much data as a transmission amount smaller than the predetermined transmission amount is transmitted to the MS.

Abstract: Disclosed is a method for controlling transmission power to be allocated to sub-carrier signals in a cellular communication system capable of dividing a frequency band into a plurality of sub-carrier bands and multiplexing the sub-carrier signals of the sub-carrier bands based on multiple frequency reuse factors.

Abstract: A method of mapping Space-Time Coding (STC) data to subcarriers in a broadband wireless communication system using multiple antennas is provided. Transmission symbols are encoded according to a predetermined space-time coding matrix and the coded data symbols are mapped to time-space-subcarriers according to a mapping rule determined by the space-time coding matrix.

Abstract: An apparatus is provided for transmitting uplink fast feedback information in a wireless communication system. In the apparatus, a channel encoder generates uplink fast feedback information to transmit, and outputs 3-bit codewords being set according to the fast feedback information. A noncoherent modulator modulates transmission symbols corresponding to the codewords using a noncoherent modulation scheme, and allocates the modulated transmission symbols to each of subcarrier bundles. An inverse fast Fourier transform (IFFT) unit IFFT-processes a transmission signal comprised of the subcarrier bundles before transmission.

Abstract: A system includes a first base station (BS) adapted to generate, upon detecting an access request signal for a second BS and transmitted from a mobile terminal (MT), an access detection message indicating the detection, and a network element coupled between the first and second BS and adapted to receive the access detection message. The second BS is adapted to receive the access detection message from the network element.

Abstract: Disclosed is a hard handover method and system for use in a Broadband Wireless Access (BWA) communication system. The method and system includes dividing a data transmission field for mobile stations (MSs) into a handover field and a normal user field, allocating at least one subchannel in the normal user field to non-handover MSs located in a non-handover region, allocating at least one subchannel in the handover field to handover MSs located in a handover region, and performing communication through the allocated at least one subchannel.

Abstract: Disclosed is a method for using various multiple antenna schemes in a baseband wireless access system is provided. According to the method, a downlink MAP message is constructed in order to support various multiple antenna schemes based on a multiple-input multiple output (MIMO), which is one of the multiple antenna schemes, so that compatibility with exiting MIMO technology having no MIMO feedback can be achieved and overhead occurring in transmission of an MAP information element can be reduced. Further, it is possible to efficiently support spatial multiplexing technology capable of transmitting multiple layers having different modulation and coding in a MIMO system.

Abstract: A method for controlling power of a shared forward link data channel for multicasting in a mobile communication system. The method includes the steps of initializing a virtual gain for each mobile terminal with which the shared forward link data channel is established, receiving power control request information from each mobile terminal to adjust the virtual gain of each mobile terminal, selecting a largest virtual gain among the adjusted virtual gains as a control power value of the shared forward link data channel, and regulating the power of the shared forward link data channel to the selected control power value.

Abstract: A method and apparatus are provided for calculating a log-likelihood ratio (LLR) for decoding in a receiver for a mobile communication system, wherein the method and apparatus determine selection bits for distinguishing four quadrants in a constellation representing signal points of transmission symbols, determine domain bits for distinguishing the signal points in each domain of the four quadrants according to a modulation order of the transmission symbols, repeat an operation of dividing a received signal into a real component and an imaginary component according to the number of determined domain bits, calculate and origin-shift absolute values of the real component and the imaginary component, and calculate LLRs for the selection bits. Further, the method and apparatus can subsequently calculate LLRs for corresponding domain bits each time the origin-shifted received signal is received.

Abstract: A method and system for transmitting reference signals in a BWA communication system using a first transmit antenna, a second transmit antenna, and a plurality of sub-carriers. Each of the sub-carriers occupies a sub-frequency domain. In the method, reference signals for identifying a first transmit antenna are transmitted through a second predetermined number of sub-carriers in a first mini sub-channel transmitted through the first transmit antenna and occupied by a predetermined time domain and sub-frequency domains of a first predetermined number of sub-carriers, and reference signals for identifying a second transmit antenna are transmitted through the second predetermined number of the sub-carriers in a second mini sub-channel transmitted through the second transmit antenna and occupied by the time domain and the sub-frequency domains of the first predetermined number of sub-carriers.

Abstract: A method for transmitting uplink control information in a communication system using an orthogonal frequency division multiple access (OFDMA) scheme is provided. A mobile station (MS) selects a target anchor base station (BS) with which the MS desires to communicate through a fast feedback channel, and transmits a codeword allocated to the selected target anchor BS to a current anchor BS. Upon receiving the codeword, transmitting to the MS, by the anchor BS, fast feedback channel allocation information for the selected BS corresponding to the received codeword. The MS switches to a new anchor BS corresponding to the fast feedback channel allocation information.