An on-off keying (OOK) transmitter and communication method are provided. The OOK transmitter may include a data encoder configured to encode input data into a transmission sequence, a pulse shaper configured to generate pulses based on the transmission sequence, a bi-phase controller configured to generate a control signal to control a random change in phase, between two phases, of a carrier based on the transmission sequence, a bi-phased switch configured to randomly change a phase of the carrier generated by a voltage-controlled oscillator (VCO), based on the control signal, and a power amplifier (PA) configured to generate a transmission signal based on the generated pulses and the carrier with the randomly changed phase. The PA may be a bi-phasing PA, and the bi-phased switch may be included in the bi-phasing PA.