An FBMC/OQAM modulator, to modulate an FBMC/OQAM signal from a binary stream, the FBMC/OQAM modulator comprising at least one QAM mapper (710, 720, 1001) to map said binary stream into at least one time domain representation of complex symbols, a first transmission chain (701, 1002) and a second transmission chain (702, 1003), each transmission chain comprising: - a precoder (730, 731, 1030, 1031) configured to transpose a first, and respectively a second, set of symbols obtained from the said complex symbols into a frequency domain representation of real, respectively imaginary, samples, - a phase rotator (512, 513) configured to apply a phase quadrature keying to the samples that output the precoder, and - an FBMC modulator (523, 533, 553, 563) configured to modulate the output of the phase rotator into a time domain representation of an FBMC symbol, the FBMC/OQAM modulator further comprising an adder to sum the output of the first transmission chain with a delayed version of the output of the second transmission chain, wherein the FBMC/OQAM modulator is further configured to insert guard interval sequences into the binary stream (715, 725, 1032) that input the QAM mapper, or into the symbols in the time domain representation (711, 721, 1011, 1021) processed by the precoders, the guard interval sequences being inserted so as to be positioned at least over samples situated substantially at the end of the first half of the FBMC symbols generated by the FBMC modulator. - a precoder (730, 731, 1030, 1031) configured to transpose a first, and respectively a second, set of symbols obtained from the said complex symbols into a frequency domain representation of real, respectively imaginary, samples, - a phase rotator (512, 513) configured to apply a phase quadrature keying to the samples that output the precoder, and - an FBMC modulator (523, 533, 553, 563) configured to modulate the output of the phase rotator into a time domain representation of an FBMC symbol, the FBMC/OQAM modulator further comprising an adder to sum the output of the first transmission chain with a delayed version of the output of the second transmission chain, wherein the FBMC/OQAM modulator is further configured to insert guard interval sequences into the binary stream (715, 725, 1032) that input the QAM mapper, or into the symbols in the time domain representation (711, 721, 1011, 1021) processed by the precoders, the guard interval sequences being inserted so as to be positioned at least over samples situated substantially at the end of the first half of the FBMC symbols generated by the FBMC modulator. the FBMC/OQAM modulator further comprising an adder to sum the output of the first transmission chain with a delayed version of the output of the second transmission chain, wherein the FBMC/OQAM modulator is further configured to insert guard interval sequences into the binary stream (715, 725, 1032) that input the QAM mapper, or into the symbols in the time domain representation (711, 721, 1011, 1021) processed by the precoders, the guard interval sequences being inserted so as to be positioned at least over samples situated substantially at the end of the first half of the FBMC symbols generated by the FBMC modulator.