A method and transmitter for transmitting an On-Off Keying, OOK, signal which comprises an ON waveform and an OFF waveform forming a pattern representing transmitted binary information as a Manchester code. For one binary value of information to be transmitted, a first set of complex-valued frequency domain symbols is provided to an inverse fast Fourier transformer, or for the other binary value of information to be transmitted, a second set of complex-valued frequency domain symbols is provided to the inverse fast Fourier transformer. The inverse fast Fourier transform is performed to form an orthogonal frequency division multiplex, OFDM representation, including a cyclic prefix, of the OOK signal of information to be transmitted. The OFDM representation is then transmitted.