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: An apparatus and method are provided for estimating a Carrier-to-Interference-and-Noise Ratio (CINR) in a communication system based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In the communication system, all base stations boost a power level for a preamble or pilot by B dB. Accordingly, a received signal power level and a received interference level are boosted by B dB, but a noise level is not boosted. Transmission power for a preamble or pilot interval is boosted as compared with that for the data interval. After an interference and noise level is estimated from a preamble or pilot, the interference and noise level estimate of the preamble or pilot is corrected by taking into account a boosting level of the preamble or pilot.

Abstract: An apparatus and a method for estimating a carrier to interference and noise ratio (CINR) in a communication system. The CINR value is precisely estimated by removing the error floor value, which is caused by the inaccurate sliding average window SAW channel estimation value, from the CINR estimation value. Since the CINR value is precisely estimated, performance of the adaptive power control or the adaptive modulation and coding device is improved.

Abstract: An apparatus and method for estimating UpLink (UL) transmission timing in a Mobile Station (MS) of a wireless communication system are provided. The method includes tracking DL timing by using a DL preamble signal received for each frame; estimating a time offset between a previous frame and a current frame by using the DL timing tracked for each frame; and estimating the UL transmission timing by using the estimated time offset.

Abstract: A decoding apparatus and method of a terminal in a wireless communication system are provided. A carrier to interference and noise ratio (CINR) estimator estimates a CINR value of a received signal, and a controller generates a modulation and coding scheme (MCS) level candidate set satisfying the estimated CINR value and a target packet error rate (PER) based on a look-up table. A decoder switch determines if an MCS level of a burst is included in the MCS level candidate set when the burst having no connection identifier (CID) information exists in a corresponding frame, and determines to decode the corresponding burst if the MCS level of the burst is included in the MCS level candidate set and to discard the burst otherwise.

Abstract: A system is provided for transmitting/receiving downlink resource allocation information in a communication system. In the system, a base station generates first information including downlink resource allocation information necessary for supporting a first mode supported by the base station, generates second information including length information of the first information, and transmits the first information and the second information. A mobile station notifies the base station of a second mode supported by the mobile station, receives, after the notification, the first information and the second information from the base station, and skips without decoding as much downlink resource allocation information as a length corresponding to the length information without decoding, if the first mode is different from the second mode.

Abstract: A method and apparatus for processing time windowing to transmit a signal in a Broadband Wireless Access (BWA) communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). A signal of a first interval included in a previous symbol prior to a current symbol is stored as a signal of a previous symbol interval. The current symbol includes a guard interval and an effective symbol interval subsequent to the guard interval. The current symbol is windowed by overlapping the stored signal of the first interval with a signal of a second interval included in the current symbol subsequent to the previous symbol. A windowed signal is transmitted.

Abstract: An apparatus and method for estimating a carrier-to-interference-and-noise ratio (CINR) of a received signal in an orthogonal frequency division multiplexing (OFDM) system are provided. A band-pass filter attenuates a signal region of the received signal and passes a signal in a noise region. A first power calculator calculates interference and noise power of the noise-region signal received from the band-pass filter. A second power calculator calculates total received power of the received signal. A ratio calculator calculates a CINR based on the interference and noise power, and the total received power.

Abstract: A method for providing a single-frequency network (SFN) service between a base station (BS) and a mobile station (MS) in a wireless communication system. The BS sets a first segment indicator in a medium access control (MAC) message field before transmission, if a resource allocation scheme corresponds to general data transmission. The BS sets a second segment indicator in the MAC message before transmission, if the resource allocation scheme corresponds to single frequency-based data transmission. The MS receives the MAC message from the BS, and performs renumbering according to the first segment indicator or the second segment indicator included in the received MAC message.

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: Disclosed is a system and method for transmitting and receiving hybrid automatic repeat request (HARQ) buffer capability information in a broadband wireless access communication system. According to the system and method, a mobile station detects its own HARQ buffer capacity, and transmits a message including information about the detected HARQ buffer capability to a base station. The base station receives the message and determines the amount of a transmission signal to be allocated to the mobile station based on the HARQ buffer capability, so that it is possible to operate a HARQ scheme in accordance with the HARQ buffer capability of the mobile station.

Abstract: An apparatus and method are provided for estimating a Carrier-to-Interference-and-Noise Ratio (CINR) in a communication system based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In the communication system, all base stations boost a power level for a preamble or pilot by B dB. Accordingly, a received signal power level and a received interference level are boosted by B dB, but a noise level is not boosted. Transmission power for a preamble or pilot interval is boosted as compared with that for the data interval. After an interference and noise level is estimated from a preamble or pilot, the interference and noise level estimate of the preamble or pilot is corrected by taking into account a boosting level of the preamble or pilot.

Abstract: Disclosed are an apparatus and method that can estimate the maximum delay spread by means of simple computation while being robust against SNR (Signal-to-Noise Ratio) variations. A standard deviation value of a noise component is produced from time-domain signal values obtained from a received signal. The time-domain signal values corresponding to preset sampling points are compared with a threshold value designated by the standard deviation value. A delay time of a time index that corresponds to a time-domain signal value equal to or larger than the threshold value and simultaneously is the maximum time index among time indexes respectively corresponding to the sampling points is detected to be a maximum delay spread value.

Abstract: In an apparatus for estimating a Carrier-to-Interference-and-Noise Ratio (CINR) in a communication system, received signals are blocked based on sub-carriers with similar channel characteristics. Interference and noise levels and true received signal levels are computed on a block-by-block basis from the blocked received signals. CINRs are estimated on a block-by-block basis using ratios between the computed interference and noise levels and the computed true received signal levels. The apparatus can estimate a CINR for all channels even when the channel characteristics of the sub-carriers of the received signals are not similar to each other.

Abstract: A cell configuration method and system and a channel allocation method for the system are disclosed for minimizing the influence of intercell interference between cells in a mobile communication system capable of providing a mobile subscriber with a stable communication service, by determining a number of safety channels to be assigned to each of the plurality of cells, and providing the adjacent cells around the serving cell with at least one additional shared safety channel other than the safety channel originally assigned to the each cell.

Abstract: An apparatus and a method for estimating a carrier to interference and noise ratio (CINR) in a communication system. The CINR value is precisely estimated by removing the error floor value, which is caused by the inaccurate sliding average window SAW channel estimation value, from the CINR estimation value. Since the CINR value is precisely estimated, performance of the adaptive power control or the adaptive modulation and coding device is improved.

Abstract: Transmitting and receiving apparatuses for PAPR reduction and an adaptive PAPR control method thereof are provided. Prior to transmission, the transmitting apparatus limits the peak of a multi-carrier modulated signal using a mapping function that increases an output value with an input value and converges the output value to a predetermined value. The receiving apparatus receives the peak-limited signal, recovers the peak of the signal using a demapping function of the mapping function, and recovers data from the peak-recovered signal according to the multi-carrier modulation scheme used. According to the adaptive PAPR control method, a scaling factor can be set variably for the mapping function and the demapping function according to a sub-carrier modulation scheme.

Abstract: A channel estimation apparatus and method for an OFDM/OFDAM receiver. A channel characteristic value, positioned prior to a pilot symbol of a current slot, from among data symbols of the current slot is estimated by a time-domain interpolation method for use with a channel characteristic value of a pilot symbol of a previous slot and a channel characteristic value of the pilot symbol of the current slot. A channel characteristic value next to the pilot symbol of the current slot from among the data symbols of the current slot is estimated by a time-domain extrapolation method for use with the channel characteristic value of the pilot symbol of the previous slot and the channel characteristic value of the pilot symbol of the current slot.

Abstract: A method and apparatus for estimating interference and noise power in an orthogonal frequency division multiplexing/orthogonal frequency division multiple access/discrete multi-tone (OFDM/OFDMA/DMT) system is disclosed. A correlator correlates a plurality of sub-carriers with a preset reference sequence on an element-by-element basis and outputs a result of the correlation. A signal noise producer calculates a difference between a correlation value associated with each of the plurality of sub-carriers output from the correlator and a correlation value produced from at least one adjacent sub-carrier and outputs a result of the calculation. An interference and noise power producer produce interference and noise power from the difference between the correlation values calculated by the signal noise producer.

Abstract: Disclosed is a method for controlling downlink power transmitted from a base station to subscriber stations in a mobile communication system employing an Orthogonal Frequency Division Multiple Access (OFDMA) scheme, in which data is carried from the base station to the subscriber stations by subchannels to each of which a plurality of subcarriers are assigned. The method includes the steps of receiving from the subscriber stations channel condition information of each of the subchannels together with information related to a subcarrier having a channel condition below a threshold from among at least one subcarrier included in each of the subchannels; calculating transmission power for each of the subchannels based on the received information; and transmitting each of the subchannels with the calculated transmission power, excluding the subcarrier having a channel condition below the threshold.