A method for transmitting data streams by a transmitter in a wireless communication system is provided. The transmitter performs Fourier transform for a data stream to generate a transformed stream. The transmitter repeats the transformed stream to generate a repeated stream. The transmitter maps the repeated stream on a plurality of subcarriers to generate a transmission signal. The transmitter transmits the transmission signal to a receiver. The plurality of subcarriers are selected by starting from a subcarrier having a predetermined index and hopping at a subcarrier interval.