A method of transmitting an On-Off Keying, OOK, signal includes an ON waveform and an OFF waveform forming a pattern representing transmitted information. The method includes obtaining a basic baseband waveform; scrambling the basic baseband waveform by applying a first binary randomised sequence where one of the binary values cause transformation to a complex conjugate, modulating the information to be transmitted by applying the scrambled basic baseband waveform for the ON waveform and applying no waveform for the OFF waveform; and transmitting the modulated information.