An OFDM-based secure data communicating scheme in GSM voice channel

A novel scheme based on OFDM mechanism which modulates encrypted data onto speech-like waveforms is presented in this paper. The modulated waveforms go through the voice channel with sufficient accuracy and are demodulated and decrypted at the receiving end. A novel model was proposed for GSM Full Rate speech codec by modulating encrypted bit stream onto orthogonal multi-frequency sinusoidal carriers. Simulation results on GSM-to-GSM connection show that the throughput can achieve 2.4kb/s with BER of 0.12%. The proposed scheme can be widely used for real-time secure data communications.