Abstract: Provided is a transmitting/receiving apparatus and method for an IDMA system. The receiving apparatus includes a channel estimator, an estimator, and a determiner. The channel estimator estimates a channel using a multi-user signal received through at least one RX antenna. The estimator estimates the noise power and the signal power for each transmission layer of each user by using the estimated channel value from the channel estimator. The determiner determines the number of transmission layers for each user and an MCS level for each transmission layer by using the signal power and the noise power estimated by the estimator.

Abstract: Methods and apparatus for spatial multiplexing in a closed-loop Multi Input Multi Output (MIMO) system are provided. In a method of operating a receiver in an MIMO system, a signal transmitted by a transmitter is received. Blockwise-Orthogonalized Spatial Multiplexing (B-OSM) is performed on the received signal. Feedback information determined by performing the B-OSM on the received signal is fed back to the transmitter.

Abstract: An apparatus and a method for improving performance of an equalizer in a wireless communication system are provided. The apparatus of a reception end includes a search unit and an estimator. The search unit determines power values of respective taps inside a window based on a signal received via a pilot channel, and classifies the taps into one or more meaningful taps and one or more noise taps. The estimator allocates one or more 1-tap channel estimators to the one or more meaningful taps, and determines a channel estimation vector based on a channel estimation value of the one or more meaningful taps determined by the one or more 1-tap channel estimators.

Abstract: A method and an apparatus for feeding back channel information in a wireless communication system are provided. The method includes calculating an average Signal to Interference and Noise Ratio (SINR), determining a Modulation and Coding Scheme (MCS) level corresponding to the average SINR, determining an MCS level meeting a predefined condition among MCS levels equal to or less than the determined MCS level, and reporting a channel quality indicator representing the determined MCS level to a base station.

Abstract: Provided are a method and an apparatus of transceiving a signal using a link adaptation in a communication system, particularly, a method of dividing a resource region into a plurality of resource regions, and applying different line adaptations to the resource regions. A method of controlling a link of a terminal in a mobile communication system receives at least two downlink channel signals to estimate states of received channels, generates a channel discrepancy report when states of channels exceed a preset threshold, and reports the channel discrepancy report to a base station through a preset uplink channel. A method of controlling a link of a base station receives a channel discrepancy report through an uplink channel, and determines MCS and transmission power of downlink channels based on the received channel discrepancy report and transmits the determined MCS and transmission power to the terminal through a downlink channel.

Abstract: An apparatus and method for detecting a signal in a Multiple-Input Multiple-Output (MIMO) system are provided. The method includes filtering each stream of a received signal, acquiring a new search space by acquiring a set of candidates having reliability greater than a threshold with respect to each filtered stream, and detecting a signal for each stream of the new search space.

Abstract: A method and apparatus for estimating a channel efficiently though pilot subcarrier signal transformation and noise reduction in the mobile communication system are provided. The apparatus includes a time domain transformer for transforming received pilot subcarrier signals to time domain signals, a noise reducer for reducing noises of the time domain signals, a frequency domain transformer for transforming the noise-reduced time domain signals to frequency domain signals, and a final channel estimator for estimating channel values of data subcarriers received using the frequency domain signals. The channel estimation method and apparatus of improves performance with the reduction of computational complexity.

Abstract: An apparatus and a method for interference cancellation in a Multiple Input Multiple Output (MIMO) wireless communication system. The method for interference cancellation includes equalizing first reception signals received through two or more reception antennas to estimate transmission signals transmitted through two or more transmission antennas, generating two or more second reception signals in which a mutual interference between the transmission signals is removed from the first reception signals by using the estimated transmission signals, independently equalizing the generated two or more second reception signals, and combining the independently equalized two or more second reception signals to estimate a transmission signal in which an interference is removed.

Abstract: A device and method is provided for iterative inter-cell interference cancellation and channel equalization in the mobile communication system. A downlink receiver of a mobile communication system according to the present invention includes a channel estimator for estimating channel impulse response of a selected cell from channel signals of respective cells; an equalizer for equalizing the channel impulse response output by the channel estimator using an equalization coefficient; a despreader for generating a symbol observation value per code channel by despreading the output of the equalizer with a code of the selected cell; and a cell interference estimator for estimating a symbol signal power and noise power of a data code channel from the symbol observation value and generates the estimated MMSE as a chip level regeneration sample.

Abstract: An apparatus and method for reporting a Channel Quality Indicator (CQI) in a wireless communication system are provided. The method includes estimating a per-subband CQI with respect to each transport layer and generating a broadband CQI with respect to each transport layer according to the per-subband CQI, comparing the broadband CQI and the per-subband CQI with respect to each transport layer to determine a difference value thereof, determining an offset value to be used in a differential CQI, determining the differential CQI by subtracting the offset value from the determined difference value, and transmitting a transmission symbol by converting the determined differential CQI into the transmission symbol.

Abstract: An apparatus and a method for improving performance of an equalizer in a wireless communication system are provided. The apparatus of a reception end includes a search unit and an estimator. The search unit determines power values of respective taps inside a window based on a signal received via a pilot channel, and classifies the taps into one or more meaningful taps and one or more noise taps. The estimator allocates one or more 1-tap channel estimators to the one or more meaningful taps, and determines a channel estimation vector based on a channel estimation value of the one or more meaningful taps determined by the one or more 1-tap channel estimators.

Abstract: Methods and apparatus are provided for performing a handover from a macro base station to a home node in the macro base station of a mobile communications system. A location of a terminal is received from the terminal at the macro base station. A handover from the macro base station to the home node to which the terminal is registered is initiated, when a distance between the location of the terminal and a location of the home node is less than a first predefined threshold. A request for an allocation of frequency and resources having a minimum interference with the macro base station for the home node is transmitted to a home node controller.

Abstract: An apparatus and a method for controlling interference in a wireless communication system are provided. The method includes receiving a signal of a DownLink (DL) frequency band that is adjacent to an UpLink (UL) frequency band supported by a User Equipment (UE), measuring a Received Signal Strength Indicator (RSSI) of the DL frequency band signal, comparing the measured RSSI with a threshold value, and, if the measured RSSI is less than the threshold value, limiting UL transmission.

Abstract: A method and apparatus for layer canceling in a multiple antenna system supporting space multiplexing are provided. The method includes determining a Log Likelihood Ratio (LLR) for each layer of signals received through a plurality of receive antennas and ordering each layer, and performing layer canceling using the ordering result.

Abstract: An apparatus and method for power control are provided. In a receiver in a mobile communication system, a Receive (Rx) signal received through a plurality of antennas is estimated. A power ratio between a traffic channel of the Rx signal and a pilot channel of the Rx signal is determined. A Log Likelihood Ratio (LLR) value is determined using the power ratio between the traffic channel and the pilot channel, a symbol of the traffic channel, and an Rx signal estimation value to which precoding is applied.

Abstract: An apparatus and method for detecting a signal in a Multiple-Input Multiple-Output (MIMO) system are provided. The method includes filtering each stream of a received signal, acquiring a new search space by acquiring a set of candidates having reliability greater than a threshold with respect to each filtered stream, and detecting a signal for each stream of the new search space.

Abstract: Methods and apparatus for spatial multiplexing in a closed-loop Multi Input Multi Output (MIMO) system are provided. In a method of operating a receiver in an MIMO system, a signal transmitted by a transmitter is received. Blockwise-Orthogonalized Spatial Multiplexing (B-OSM) is performed on the received signal. Feedback information determined by performing the B-OSM on the received signal is fed back to the transmitter.

Abstract: An apparatus and method for reporting a Channel Quality Indicator (CQI) in a wireless communication system are provided. The method includes estimating a per-subband CQI with respect to each transport layer and generating a broadband CQI with respect to each transport layer according to the per-subband CQI, comparing the broadband CQI and the per-subband CQI with respect to each transport layer to determine a difference value thereof, determining an offset value to be used in a differential CQI, determining the differential CQI by subtracting the offset value from the determined difference value, and transmitting a transmission symbol by converting the determined differential CQI into the transmission symbol.

Abstract: A cell search apparatus and method in a mobile communication system. After a UE acquires slot boundary timing and frame boundary timing to a Node B, it acquires its scrambling code number and scrambling code timing. After the initial cell search, the UE performs multi-path search by searching a first area with respect to the scrambling code timing. During reacquisition in a sleep state, the UE searches a second area wider than the first area with respect to a scrambling code timing acquired before the sleep state. The UE performs neighbor cell search by selectively using the initial cell search and the multi-path search according to whether the Node B provides information or what information it provides.

Abstract: A synchronization (sync) code communication device for a CDMA communication system. A base station sync code transmission device comprises a primary sync code transmitter and a secondary sync code transmitter. The primary sync code transmitter is for generating and then transmitting a primary sync code at a first location in a transmission frame. The primary sync code is for acquiring synchronization at a starting point of a frame and the frame is equal to one period of a spreading code. The secondary sync code transmitter is for generating and then transmitting a secondary sync code at a second location in a frame. The secondary sync codes are assigned to base station groups, one to a group. A mobile station sync code receiving device comprises a primary sync code acquisition decider and a base station group decider. The primary sync code acquisition decider is for acquiring a primary sync code received at a first location in a frame, and then acquiring synchronization at a starting point of a frame.