Abstract: An iterative detection and decoding method in a Multiple Input Multiple Output (MIMO) system includes detecting entire MIMO nodes to generate soft decision values; decoding a first soft decision value among the soft decision values; determining whether to perform an iterative detection and decoding by measuring reliability of the decoded first decoding signal; generating a soft decision value by performing a redetection of a MIMO node containing the soft decision value, when the decoded soft decision value is iteratively detected and decoded; and decoding a second soft decision value among the soft decision values.

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: Detection of a signal in a receiver of a MIMO communication system includes a transmitter for signals transmission via K antennas and a receiver for receiving the signals via L reception antennas, such that L is greater than or equal to K and the system has a K×L-dimensional channel matrix, by converting the channel matrix into a plurality of matrixes having an upper triangle structure; dividing each of the matrixes into at least two sub-matrixes having a dimension lower than that of the channel matrix; detecting transmission symbols from corresponding antennas through decoding of a) lowest sub-matrix signal received which sub-matrix is constituted of components having only the channel characteristics of two antennas among the two sub-matrixes; and b) an upper sub-matrix signal using the transmission symbols; and outputting all of the detected transmission symbols, if transmission symbols by a highest sub-matrix among at least two sub-matrixes are detected.

Abstract: Provided is an apparatus and method for calibrating a channel in a radio communication system using multiple antennas. A base station apparatus for the radio communication system includes a channel estimator and a calculator. The channel estimator receives a UL sounding signal to estimate a first UL CSI and receives a UL sounding signal weighted with a DL CSI to estimate a second UL CSI. The calculator calculates calibration values for the respective antenna pairs using the first UL CSI and the second UL CSI. Information necessary for channel calibration is transmitted and received in an analog format. Accordingly, it is possible to minimize the waste of resource and time necessary for channel calibration.

Abstract: An apparatus and method for simultaneously providing service to users each having a different number of antennas in a multiple-antenna wireless communication system are provided. The communication method discloses a BS in a wireless communication system that services a first multiple antenna mode using X transmit antennas and a second multiple antenna mode using Y transmit antennas such that (Y>X), the BS determines an MS to be serviced in the second multiple antenna mode and receives a sounding signal from the MS. The BS estimates an uplink channel using the received sounding signal and acquires downlink channel values using estimated uplink channel values. Then the BS services the MS in the second multiple antenna mode using the downlink channel values.

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: Provided is an apparatus and method for simultaneously receiving data signals of two adjacent frequency allocation (FA) in a cellular environment. When there is another base station using an adjacent FA to an FA of the base station, a subcarrier mapper maps control information to subcarriers of predetermined sections such that a mobile station simultaneously receives data signals of the adjacent FAs. An inverse fast Fourier transform (IFFT) processor IFFT-processes data mapped to the subcarriers. Because two different BSs transmit the same data through independent paths, the mobile station can obtain a macro diversity gain. Also, it is possible to balance the loads of the two BSs.

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: Provided is a method for determining handover of a mobile station by a serving base station in a mobile communication system. The method includes receiving traffic quality information from the mobile station; determining whether the traffic quality information satisfies a preset setting condition; if the traffic quality information satisfies the setting condition, sending a request for pilot signal strength measurement for the serving base station and adjacent base stations to the mobile station; receiving pilot signal strengths of the base stations, reported by the mobile station; determining whether there is a corresponding base station whose pilot signal strength exceeds the pilot signal strength of the serving base station; and determining handover of the mobile station to the corresponding base station.