Ofdm generation apparatus in a multi-carrier data transmission system

An Orthogonal Frequency-Division Multiplexing (OFDM) generation apparatus for generating OFDM transmission signals from OFDM symbols, each comprising a plurality of OFDM subcarriers, for transmission in a multi-carrier data transmission system, said apparatus comprising:

• circuitry configured to
• inverse Discrete Fourier Transform (DFT) an OFDM symbol into complex time-domain samples;
• and
• mix said complex time-domain samples of said OFDM symbol from a baseband frequency up to a passband frequency by use of a mixing frequency fc to obtain an OFDM transmission signal, wherein
• the circuitry selects the mixing frequency fc such that common phase rotations of the OFDM subcarriers of said OFDM symbol with respect to adjacent OFDM symbols of said OFDM transmission signal are avoided or compensated after said mixing.

An Orthogonal Frequency-Division Multiplexing (OFDM) generation apparatus for generating OFDM transmission signals from OFDM symbols, each comprising a plurality of OFDM subcarriers, for transmission in a multi-carrier data transmission system, said apparatus comprising:

• an inverse transformation circuit that performs an inverse Discrete Fourier Transform (DFT) of an OFDM symbol into complex time-domain samples;
• and
• a frequency mixing means configured to mix said complex time-domain samples of said OFDM symbol from a baseband frequency up to a passband frequency by use of a mixing frequency fc to obtain an OFDM transmission signal, wherein
• the mixing frequency fc is selected such that common phase rotations of the OFDM subcarriers of said OFDM symbol with respect to adjacent OFDM symbols of said OFDM transmission signal are avoided or compensated after said mixing.

An Orthogonal Frequency-Division Multiplexing (OFDM) generation method for generating OFDM transmission signals from OFDM symbols, each comprising a plurality of OFDM subcarriers, for transmission in a multi-carrier data transmission system, said method comprising:

• inverse discrete Fourier transforming, by circuitry, an OFDM symbol into complex time-domain samples;
• and
• mixing, by the circuitry said complex time-domain samples of said OFDM symbol from a baseband frequency up to a passband frequency by use of a mixing frequency fc to obtain an OFDM transmission signal, wherein
• the mixing frequency fc is selected such that common phase rotations of the OFDM subcarriers of said OFDM symbol with respect to adjacent OFDM symbols of said OFDM transmission signal are avoided or compensated after said mixing.