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: 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: 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.