Abstract: A method and a system for transmitting data by a transmitter over a channel having a predetermined channel quality estimate, comprises the steps of splitting (S2P) input data stream (S40, S60, S80) to be transmitted into a plurality of data sub-streams (S40a, S40b, S40c); processing (SYM1, SYM2, SYMj) each of the plurality of data sub-streams (S40a, S40b, S40c) into a plurality of symbol subsets (S41, S42, S43) by selecting a certain scheme of coded-modulation (BPSK, QPSK, 16-QAM); processing, separately, each of the plurality of symbol subsets (S41, S42, S43), via a plurality of separate Discrete Fourier Transforms (DFT1, DFT2, DFT3), herein after denoted as DFTs, to obtain a plurality of DFT-precoded data sub-streams (S44, S45, S46); allocating each DFT-precoded data sub-stream (S44, S45, S46) in a frequency resource block (RB1, RB2, RB3), via a sub-carrier mapping module (SCM), so that for each data sub-stream (S40a, S40b, S40c) the selected scheme of coded-modulation (BPSK, QPSK, 16-QAM) is chosen in depe