Abstract: An apparatus and method for channel estimation in a wireless communication system are provided, in which a first channel estimate is calculated using a pilot signal included in a received signal, a data signal included in the received signal is demodulated using the first channel estimate, a second channel estimate is calculated using the demodulated data signal, the first channel estimate is corrected using the second channel estimate and the data signal is demodulated using the corrected first channel estimate.

Abstract: An apparatus and method for receiving a signal in a communication system are provided. Information related to a first modulation scheme applied to a frequency domain in a serving base station is received from the serving base station. Information related to a second modulation scheme applied to the frequency domain in at least one neighbor base station is received from the at least one neighbor base station. A signal is received in the frequency domain. Channel state information is generated by estimating the received signal. A determination is made as to whether to use interference cancellation using the channel state information, the first modulation scheme information and the second modulation scheme information.

Abstract: A method is provided for transmitting/receiving data in a communication system. The method includes determining, when data to be transmitted to at least one Mobile Station (MS) is generated, a region where an MS that receive the generated data among the at least one MS is located, allocating resources of a data transmission region divided into a first region and a second region to the MS that receive the generated data according to the determination result, including the generated data in a region where the resource is allocated, and including, in a MAP message region, resource allocation information of the region where the data is included and information on an MS that receive the data included in the resource-allocated region, and transmitting, to the MS, a frame including the region in which the generated data is included, and the MAP message region.

Abstract: In a communication system, information regarding a first modulation scheme applied to a frequency domain in a serving base station is received from the serving base station. A signal of the frequency domain is received. A second modulation scheme is set by estimating a modulation scheme applied to the frequency domain in at least one neighbor base station from the received signal. Channel state information is generated by estimating the received signal. An operation for selecting whether to use interference cancellation is performed using the channel state information, the first modulation scheme information and the second modulation scheme.

Abstract: A symbol demapping method and apparatus for efficient interference cancellation in a wireless communication system. Decision signal points are generated which include decision signal points based on a modulation scheme and a virtual signal point added to a zero point. A magnitude of a complex value of an input signal is compared with a threshold based on system setting. When the magnitude of the complex value is less than the threshold, the virtual signal point of the zero point is mapped and output as a target decision signal point. When the magnitude of the complex value is greater than or equal to the threshold, one of the decision signal points based on the modulation scheme is mapped and output according to the com0plex value.

Abstract: A method for allocating resource in a communication system. The resource allocation method includes dividing a data transmission region into a first region and a second region; allocating resource of the first region when a first Mobile Station (MS) among MSs is an MS located in a non-interference region; and allocating resource of the second region when a second MS among the MSs is an MS located in an interference region.

Abstract: A partial iterative detection and decoding apparatus in a Multiple Input Multiple Output (MIMO) system includes a detector for detecting signals received through at least one receive antenna to generate a first soft decision value, a decoder for decoding the first soft decision value to generate a second soft decision value, and a reliability determiner for determining a signal to be iteratively detected and decoded by using the second soft decision value. Accordingly, the complexity of the receiver is reduced and the number of iterations limited due to the complexity is increased, thereby improving the performance of the receiver.

Abstract: An Iterafive Detection and Decoding (IDD) receiving apparatus and method in a multiple input multiple output (MIMO) communication system. The IDD receiving apparatus includes an MIMO detector which generates soft decision values of coded bits by MIMO-decoding a receive vector, feedback priori information, and a list of candidate coded symbol vectors; a decoder which Soft-Input/Soft-Output (SISO)-decodes the soft decision values generated at the MIMO detector and feeds back soft decision values of the coded bits to the MIMO detector; a hard decision part which generates a coded symbol vector by performing a hard decision on the soft decision values generated at the decoder; and a list updater which generates a list of candidate coded symbol vectors using the receive vector and provides the list to the MIMO detector at a first iteration, updates the list using the coded symbol vector fed from the hard decision part, and provides the updated list to the MIMO detector at subsequent iterations.

Abstract: A Log-Likelihood Ratio (LLR) generating apparatus and method in a communication system using a spatial multiplexing scheme. The reception method includes acquiring at least one estimated transmit vector by demodulating a receive vector using at least one Multiple Input Multiple Output (MIMO) detection process; selecting one of the at least one estimated transmit vector as an optimum estimated transmit vector; calculating LLRs with respect to the optimum estimated transmit vector; calculating a weight to be applied to each of elements constructing the optimum estimated transmit vector; and applying the weight to each of the calculated LLRs. Accordingly, the present invention can generate the LLRs with high reliability similar to the LLRs of a Maximum Likelihood receiver by applying the weight to the LLRs generated from the estimated transmit vector.

Abstract: Provided are a spatial multiplexing apparatus and method in a Multiple Input Multiple Output (MIMO) system. The spatial multiplexing detection method includes estimating channels of a received signal, and sorting the estimated channels in descending order according to a scheme; generating a subsystem of a minimum unit by nulling an arbitrary channel among the sorted channels; performing a modified maximum likelihood (MML) in the subsystem of the minimum unit to calculate a number of transmission signal vectors; and calculating Euclidean distances of the number of the transmission signal vectors, and selecting a transmission signal vector having a minimum Euclidean distance. Accordingly, the receiver exhibits a performance level similar to a Maximum Likelihood (ML) and can obtain the complexity similar to successive interference cancellation (SIC).

Abstract: Disclosed is a method for determining handover of a mobile station by a mobile station in a mobile communication system. The method includes measuring a downlink reference signal intensity of a serving base station; determining to perform scanning for measurement of reference signal intensities of the serving base station and neighbor base stations, when the measured downlink reference signal intensity of the serving base station is less than a reference value, negotiating with the serving base station for a scanning period and the number of scanning repetitions, measuring the reference signal intensities of the serving base station and the neighbor base stations, and resetting the reference value when a reference signal intensity of the serving base station is greater than or equal to reference signal intensities of neighbor base stations.

Abstract: A transmission antenna diversity method, and a base station apparatus and a mobile station apparatus therefor in a mobile communication system are provided. In the transmission antenna diversity method, channel information is measured from signals received through the plurality of antennas used in the base station, and a channel information matrix is output. The channel information matrix is transformed according to a transform matrix composed of a complex basis vector set. Reception power with respect to the plurality of antennas is calculated based on the transformed channel information matrix. Antenna selection information obtained based on the calculated reception power is transmitted to the base station as feedback information for controlling transmission antenna diversity. Therefore, power is equally distributed to transmitting antennas, excellent performance is maintained at a high speed of movement, and reliable channel adaptation is accomplished at a low speed of movement of the mobile station.

Abstract: Provided are a mobile communication apparatus including an antenna array and a mobile communication method. The mobile communication apparatus has a base station and a mobile station. The mobile station measures the downlink characteristics, detects physical space information and approximate long-term information, produces short-term informatio, transforms the short-term information and the physical space information into a feedback signal, and transmits the feedback signal to the base station. The base station receives the feedback signal, extracts weighted information, beamforms dedicated physical channel signals, combines pilot channel signals with the result of the beamforming, and transmits the results of the combinations to the mobile station via the antenna array. The physical space information denotes space information about the location of the mobile station with respect to the base station, and the approximate long-term information denotes long-term information.

Abstract: Provided are a mobile communication apparatus including an antenna array and a mobile communication method. The mobile communication apparatus has a base station and a mobile station. The mobile station measures the downlink characteristics, detects physical space information and approximate long-term information, produces short-term informatio, transforms the short-term information and the physical space information into a feedback signal, and transmits the feedback signal to the base station. The base station receives the feedback signal, extracts weighted information, beamforms dedicated physical channel signals, combines pilot channel signals with the result of the beamforming, and transmits the results of the combinations to the mobile station via the antenna array. The physical space information denotes space information about the location of the mobile station with respect to the base station, and the approximate long-term information denotes long-term information.

Abstract: A wireless communication system with feedback and a method therefore, wherein the wireless communication system, which has a plurality of transmitting antennas and a plurality of receiving antennas through which signals are transmitted and received, respectively, includes: a transmitter that restores feedback information from a predetermined feedback signal, weights an information signal with the restored feedback information, and converts the weighted information signal to a radio frequency signal in order to transmit the radio frequency signal; and a receiver that receives the radio frequency signal to estimate the state of a channel, through which the radio frequency signal is transmitted, calculates a weight of a dimensionality corresponding to the number of the transmitting antennas, approximates the weight as lower-dimensional one to extract feedback information, and converts the feedback information into a radio frequency signal to send the radio frequency signal to the transmitter.

Abstract: A transmission antenna diversity method, and a base station apparatus and a mobile station apparatus therefor in a mobile communication system are provided. In the transmission antenna diversity method, channel information is measured from signals received through the plurality of antennas used in the base station, and a channel information matrix is output. The channel information matrix is transformed according to a transform matrix composed of a complex basis vector set. Reception power with respect to the plurality of antennas is calculated based on the transformed channel information matrix. Antenna selection information obtained based on the calculated reception power is transmitted to the base station as feedback information for controlling transmission antenna diversity. Therefore, power is equally distributed to transmitting antennas, excellent performance is maintained at a high speed of movement, and reliable channel adaptation is accomplished at a low speed of movement of the mobile station.

Abstract: A wireless communication system with feedback and a method therefore, wherein the wireless communication system, which has a plurality of transmitting antennas and a plurality of receiving antennas through which signals are transmitted and received, respectively, includes: a transmitter that restores feedback information from a predetermined feedback signal, weights an information signal with the restored feedback information, and converts the weighted information signal to a radio frequency signal in order to transmit the radio frequency signal; and a receiver that receives the radio frequency signal to estimate the state of a channel, through which the radio frequency signal is transmitted, calculates a weight of a dimensionality corresponding to the number of the transmitting antennas, approximates the weight as lower-dimensional one to extract feedback information, and converts the feedback information into a radio frequency signal to send the radio frequency signal to the transmitter.