A method of transmitting, by a transmitting device, an orthogonal frequency division multiplexing (OFDM) signal in a wireless communication system, the method including: generating, by a digital module of the transmitting device, a frequency-shifted OFDM baseband signal by performing frequency up-shift of a first signal by a difference between a carrier frequency f0 and a first frequency fbase, wherein the first frequency fbase is, among frequencies corresponding to integer multiples of 128Δf, closest to the carrier frequency f0, and wherein Δf is an OFDM subcarrier spacing; up-converting, by an analog oscillator of the transmitting device, the frequency-shifted OFDM baseband signal by the first frequency fbase to generate an OFDM symbol signal at the carrier frequency f0; and transmitting the OFDM symbol signal at the carrier frequency f0.