Informatica

This paper presents a novel data modulation scheme PCCD-OFDM-ASK: the phase continuous context dependent orthogonal frequency division multiplexing amplitude shift keying. The proposed modulation is successfully applied in the mobile payment system. It is used to transmit the digital data over the speech channel of the mobile communication system GSM, as well as CDMA. The main key points of the proposed modulation schemes are: precise signal synchronization between the modulator and demodulator, signal energy independent operation, on line adaptation of frequency characteristics of the transmission channel, and controlled frequency bandwidth thus enabling non-overlapped full duplex communication over the GSM's voice channel.