A method for modulation in a transmitter for transmitting a signal in a wireless communication system according to an embodiment of the present invention comprises: a step for determining a modulation scheme; a step for, if the determined modulation scheme corresponds to a specific modulation scheme, converting encoded information bits to quadrature amplitude modulation (QAM) symbols in accordance with a predetermined QAM modulation order, selecting a sequence corresponding to an element of an integer vector in a predetermined sequence set, repeating the converted QAM symbols for a predetermined sequence length, and outputting signals by multiplying the repeated QAM symbols and the selected sequence; and a step for transmitting the outputted signals to a receiver.