Embodiments of the invention relate to a method of generating digital multi-carrier frequency division multiplexing (FDM) signals, the signals comprising FDM symbols having pilot symbols, wherein at least one FDM symbol has pilot symbols which are non-equidistantly spaced in frequency. Other embodiments of the invention relate to a method of processing multi-carrier frequency division multiplexing (FDM) signals, the method comprising the following steps: a) demodulating digital multi-carrier FDM signals, said signals being comprised of FDM symbols having pilot symbols, the pilot symbols of at least one FDM symbol being non-equidistantly spaced in frequency, b) replacing, on a sub-carrier basis, at least one data symbol with a pilot symbol, whereby the replacement yields a spacing of pilot symbols which is equidistant in frequency for all FDM symbols.