Patent ID: 8885753

Claim:
A method for transmitting an orthogonal frequency division multiplex (OFDM) data signal by a transmission unit of a wireless multiple-input/multiple-output (MIMO) communication system, the transmission unit comprising a plurality of transmission antenna ports, the method comprising: performing a first transmission of an OFDM data signal, the first transmission comprising transmitting the OFDM data signal by each one of the plurality of transmission antenna ports; performing a second transmission of the OFDM data signal at a time later than the first transmission, the second transmission comprising transmitting at least one spectrally modified signal variant of the OFDM data signal by at least one transmission antenna port of the plurality of transmission antenna ports, wherein the first transmission is represented by a first channel matrix and the second transmission is represented by a second channel matrix, and transmitting at least one spectrally modified signal variant of the OFDM data signal comprises pre-coding a signal component of the OFDM data signal, the pre-coding being performed in the frequency domain by applying at least two different multiplicative factors to different subcarriers for a frequency-dependent multiplication to the respective signal component of the OFDM data signal; and selecting the at least two multiplicative factors in such a way so as to construct a further channel matrix based on the second channel matrix, wherein the further channel matrix comprises a rank that is higher than a rank of the first channel matrix.