Mobile communication system, receiving device, and method

A mobile communication system employing a single-carrier multiple-input multiple-output (MIMO) transmission scheme, comprising:

• a transmitting device including
• a mapping unit configured to map Fourier-transformed and weighted symbols in a transmission symbol sequence to subcarriers,
• an inverse Fourier transform unit configured to inverse-Fourier-transform the mapped symbols, and
• a transmitting unit configured to transmit a signal including the inverse-Fourier-transformed symbols from multiple transmitting antennas;
• and
• a receiving device including
• an extracting unit configured to Fourier-transform signals received by multiple receiving antennas and to extract signal components mapped to the subcarriers from the signals, and
• a signal detection unit configured to estimate the symbols transmitted via the subcarriers by applying a QR decomposition algorithm to the extracted signal components,
• wherein the signal detection unit includes
• a decomposition unit configured to obtain a unitary matrix such that a product of the unitary matrix and a triangular matrix equals a product of a weight matrix determining a correspondence between the transmission symbol sequence and the subcarriers and a channel matrix indicating radio channel conditions between the transmitting antennas and the receiving antennas;
• and
• an estimation unit configured to estimate candidates of the symbols transmitted from the transmitting antennas based on the triangular matrix and a vector obtained by multiplying a received vector, which includes the signal components received by the receiving antennas, by the unitary matrix.

A method for a mobile communication system employing a single-carrier multiple-input multiple-output (MIMO) transmission scheme and including a transmitting device and a receiving device, the method comprising:

• the steps, performed by the transmitting device, of mapping Fourier-transformed and weighted symbols in a transmission symbol sequence to subcarriers,
• inverse-Fourier-transforming the mapped symbols, and
• transmitting a signal including the inverse-Fourier-transformed symbols from multiple transmitting antennas;
• and
• the steps, performed by the receiving device, of
• Fourier-transforming signals received by multiple receiving antennas and extracting signal components mapped to the subcarriers from the signals, and
• estimating the symbols transmitted via the subcarriers by applying a QR decomposition algorithm to the extracted signal components,
• wherein in the estimating step,
• a unitary matrix is obtained such that a product of the unitary matrix and a triangular matrix equals a product of a weight matrix determining a correspondence between the transmission symbol sequence and the subcarriers and a channel matrix indicating radio channel conditions between the transmitting antennas and the receiving antennas, and
• candidates of the symbols transmitted from the transmitting antennas are estimated based on the triangular matrix and a vector obtained by multiplying a received vector, which includes the signal components received by the receiving antennas, by the unitary matrix.