Abstract: A method of an electronic device is provided. The method includes receiving signals from adjacent base stations comprising a first base station and a second base station, respectively, detecting a first synchronization signal and a second synchronization signal for the first base station among the received signals, estimating a first signal corresponding to the detected first synchronization signal and second synchronization signal, eliminating the first signal among the signals received from the adjacent base stations, and detecting a second signal for the second base station.

Abstract: A method of an electronic device is provided. The method includes receiving signals from adjacent base stations comprising a first base station and a second base station, respectively, detecting a first synchronization signal and a second synchronization signal for the first base station among the received signals, estimating a first signal corresponding to the detected first synchronization signal and second synchronization signal, eliminating the first signal among the signals received from the adjacent base stations, and detecting a second signal for the second base station.

Abstract: An apparatus and a method for canceling interference based on Maximum Likelihood (ML) at a receiver of a multi-antenna system are provided. The method includes estimating a channel using a signal received over one or more receiver antennas; generating one or more weights using the estimated channel to cancel interference; detecting a candidate symbol having the shortest Euclidean distance through Maximum Likelihood using a first weight; and soft-decoding the candidate symbol using a second weight. Therefore, by receiving the signal based on the ML under the interference, the system capacity can be increased and the reception performance can be enhanced.

Abstract: An apparatus and method for lowering a tree searching complexity in a Spatial Multiplexing (SM) Multiple Input Multiple Output (MIMO) antenna system are provided. A transmitting apparatus includes a generator for generating a plurality of transmit streams by spatial-multiplexing a transmit data, a determiner for determining modulation schemes to be applied to the plurality of the transmit streams respectively and a modulator for modulating the plurality of the transmit streams using at least two modulation schemes under control of the determiner. The receiver detects the signals by allocating the modulation scheme of the lowest order to the upper tree level.

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: Receiving apparatus and method in a Multiple-Input Multiple-Output (MIMO) wireless communication system are provided. The receiver having N-ary receive antennas includes a decomposer for decomposing a channel matrix to a matrix Q and a matrix R through a QR decomposition; a detector for determining a candidate group of an n-th phase by estimating a plurality of transmit signal vectors by substituting a plurality of transmittable symbols into symbol combinations of a candidate group of a (n?1)-th phase as an n-th symbol and detecting (n+1)-th through N-th symbols using characteristics of the matrix R; a calculator for calculating square Euclidean distance values between the transmit signal vectors and a receive signal vector; and a determiner for determining the candidate group of the n-th phase by selecting transmit signal vectors having the smallest square Euclidean distance value among the transmit signal vectors.

Abstract: An apparatus and method for detecting a signal in a receiver by maximum likelihood (ML) are provided, in which symbols are detected according to the number of transmit antennas of a transmitter and a modulation scheme, channels are estimated, an equivalent channel matrix corresponding to the estimated channels is determined, a permuted equivalent channel matrix is determined by multiplying the equivalent channel matrix by a predetermined permutation matrix, the permuted equivalent channel matrix is QR decomposed, a hard decision is performed on predetermined symbols among the detected symbols using a received signal resulting from the QR decomposition, and the log likelihood ratios (LLRs) of the hard-decided symbols are determined.

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: A receiver and a receiving method for a Single Carrier Frequency Division Multiple Access (SC-FDMA) system are provided. The receiver includes a matrix selector for selecting a constant channel matrix according to a Multiple-Input Multiple-Output (MIMO) reception scheme, a channel equalizer for equalizing a multi-path channel to a specific path channel in a frequency domain by using the constant channel matrix, and a MIMO detector for detecting a Euclidean distance of transmittable symbols from a time-domain Transmit (Tx) signal by using the channel equalized in the frequency domain and then for selecting a symbol having a minimum distance.

Abstract: An apparatus and method for generating LLRs in an MIMO communication system. In a receiver for a spatial multiplexing communication system, a determiner performs an MML decoding operation in an ascending or descending order of TX antennas to estimate a plurality of candidate TX vectors. A distance calculator calculates a Euclidean distance for each of the candidate TX vectors from the determiner. An LLR calculator calculates LLRs using the Euclidean distances from the distance calculator. Accordingly, it is possible to generate an LLR with high reliability at low complexity in an MIMO communication system.

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: An Iterative 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 receiver and a receiving method for a Single Carrier Frequency Division Multiple Access (SC-FDMA) system are provided. The receiver includes a matrix selector for selecting a constant channel matrix according to a Multiple-Input Multiple-Output (MIMO) reception scheme, a channel equalizer for equalizing a multi-path channel to a specific path channel in a frequency domain by using the constant channel matrix, and a MIMO detector for detecting a Euclidean distance of transmittable symbols from a time-domain Transmit (Tx) signal by using the channel equalized in the frequency domain and then for selecting a symbol having a minimum distance.

Abstract: An apparatus and a method for canceling interference based on Maximum Likelihood (ML) at a receiver of a multi-antenna system are provided. The method includes estimating a channel using a signal received over one or more receiver antennas; generating one or more weights using the estimated channel to cancel interference; detecting a candidate symbol having the shortest Euclidean distance through Maximum Likelihood using a first weight; and soft-decoding the candidate symbol using a second weight. Therefore, by receiving the signal based on the ML under the interference, the system capacity can be increased and the reception performance can be enhanced.

Abstract: An apparatus and method for detecting a signal in a receiver by maximum likelihood (ML) are provided, in which symbols are detected according to the number of transmit antennas of a transmitter and a modulation scheme, channels are estimated, an equivalent channel matrix corresponding to the estimated channels is determined, a permuted equivalent channel matrix is determined by multiplying the equivalent channel matrix by a predetermined permutation matrix, the permuted equivalent channel matrix is QR decomposed, a hard decision is performed on predetermined symbols among the detected symbols using a received signal resulting from the QR decomposition, and the log likelihood ratios (LLRs) of the hard-decided symbols are determined.

Abstract: Receiving apparatus and method in a Multiple-Input Multiple-Output (MIMO) wireless communication system are provided. The receiver having N-ary receive antennas includes a decomposer for decomposing a channel matrix to a matrix Q and a matrix R through a QR decomposition; a detector for determining a candidate group of an n-th phase by estimating a plurality of transmit signal vectors by substituting a plurality of transmittable symbols into symbol combinations of a candidate group of a (n?1)-th phase as an n-th symbol and detecting (n+1)-th through N-th symbols using characteristics of the matrix R; a calculator for calculating square Euclidean distance values between the transmit signal vectors and a receive signal vector; and a determiner for determining the candidate group of the n-th phase by selecting transmit signal vectors having the smallest square Euclidean distance value among the transmit signal vectors.

Abstract: An apparatus and method for canceling interference from other MSs in an space-division wireless communication system are provided. The apparatus and method include a subframe for transmitting control information from a BS to MSs which is configured in a first region of the frame, and a subframe for transmitting and receiving signals between the BS and the MSs which is configured in a second region of the frame. The apparatus and method reduce consumption of time and frequency resources in a wireless communication system.

Abstract: An apparatus and method for lowering a tree searching complexity in a Spatial Multiplexing (SM) Multiple Input Multiple Output (MIMO) antenna system are provided. A transmitting apparatus includes a generator for generating a plurality of transmit streams by spatial-multiplexing a transmit data, a determiner for determining modulation schemes to be applied to the plurality of the transmit streams respectively and a modulator for modulating the plurality of the transmit streams using at least two modulation schemes under control of the determiner. The receiver detects the signals by allocating the modulation scheme of the lowest order to the upper tree level.

Abstract: An apparatus and method for generating LLRs in an MIMO communication system. In a receiver for a spatial multiplexing communication system, a determiner performs an MML decoding operation in an ascending or descending order of TX antennas to estimate a plurality of candidate TX vectors. A distance calculator calculates a Euclidean distance for each of the candidate TX vectors from the determiner. An LLR calculator calculates LLRs using the Euclidean distances from the distance calculator. Accordingly, it is possible to generate an LLR with high reliability at low complexity in an MIMO communication system.