Digital watermarking of audio signals for robust hidden audio communication via air audio channel

The article presents a digital audio watermarking method for air audio data transmission. The digital watermark occupies the whole frequency range of the audio signal. The digital watermark encodes one bit of information. A decision about transmitted bit is based on a sign of the center value of the mutual correlation function. Two methods to design the digital audio watermark are presented. Low complexity of presented methods of digital audio watermarking makes them suitable for use in smartphones. The method can be used in digital audio watermarking of both speech and music. Information is embedded via the digital watermark in the frequency domain of a host audio signal via amplitude modulation of its frequency constituents. The paper includes results of simulation modeling and natural experiments.