A method and apparatus for simplifying a structure needed to delay data in delay units when a reference signal and data are transmitted by using chaotic signals are provided. The method includes delaying data by at least two delay times, wherein each of the delay times occurs sequentially; multiplexing the data, which has been delayed, according to a control signal; and transmitting the data and a reference signal which corresponds to the data at an interval of delay time. The apparatus includes a first delay unit which is configured to delay data for a first delay time; a second delay unit which is configured to delay the data output from the first delay unit for a second delay time; and a multiplexer which is configured to multiplex the data from the first and second delay units according to a control signal.