Abstract: A mobile device that generates and transmits a human-inaudible acoustic signal, which encodes a symbol sequence representing a binary message, for delivery as audio content, is disclosed. The mobile device encodes the binary message into a sequence of symbols that are each associated with frequency characteristics and generates and transmits the human-inaudible acoustic signal, based on the frequency characteristics of the symbols. A further mobile device that receives and decodes a human-inaudible acoustic signal, which encodes a symbol sequence representing a binary message, embedded within audio content, is disclosed. The mobile device repeatedly performs a frequency domain transformation of samples of the signal to generate a symbol sequence, and performs error correction decoding upon the symbol sequence to determine the validity of the symbol sequence.

Abstract: A sonic signal encodes a symbol sequence representing a binary message, for delivery as audio content. The binary message into a sequence of symbols that are each associated with frequency characteristics transmitted over a time period. Two carriers are transmitted at two selected frequencies during each time period, delivering the binary data at a high rate. The symbol sequence is preceded by a prefix which takes the form of a sweeping frequency tone which sweeps over the frequency ranges of the carriers. Further, the amplitudes of the carriers are adjusted so that higher frequency transmissions are transmitted at higher sound pressure levels. Methods for synchronizing to the symbol sequence and decoding the symbol sequence are also described.

Abstract: A disclosed device is configured to generate and transmit a sonic signal that encodes a symbol sequence, representing a data message, for delivery as audio content. The device includes an audio transmitter and a processor circuit. The processor circuit is configured to encode the data message as a sequence of symbols, with each symbol encoding a data value that is associated with respective phase characteristics of a transmitted audio carrier. The processor is further configured to generate audio samples of a digitized version of the sequence of symbols using the phase characteristics of the audio carrier associated with the symbols, and to control the audio transmitter to generate and transmit the sonic signal, based on the audio samples. A further disclosed device is configured to receive the sonic signal and to decode a symbol sequence by identifying symbols corresponding to determined phases of the sonic signal.

Abstract: A disclosed device is configured to generate and transmit a sonic signal that encodes a symbol sequence, representing a data message, for delivery as audio content. The device includes an audio transmitter and a processor circuit. The processor circuit is configured to encode the data message as a sequence of symbols, with each symbol encoding a data value that is associated with respective phase characteristics of a transmitted audio carrier. The processor is further configured to generate audio samples of a digitized version of the sequence of symbols using the phase characteristics of the audio carrier associated with the symbols, and to control the audio transmitter to generate and transmit the sonic signal, based on the audio samples. A further disclosed device is configured to receive the sonic signal and to decode a symbol sequence by identifying symbols corresponding to determined phases of the sonic signal.

Abstract: A sonic signal encodes a symbol sequence representing a binary message, for delivery as audio content. The binary message into a sequence of symbols that are each associated with frequency characteristics transmitted over a time period. Two carriers are transmitted at two selected frequencies during each time period, delivering the binary data at a high rate. The symbol sequence is preceded by a prefix which takes the form of a sweeping frequency tone which sweeps over the frequency ranges of the carriers. Further, the amplitudes of the carriers are adjusted so that higher frequency transmissions are transmitted at higher sound pressure levels. Methods for synchronizing to the symbol sequence and decoding the symbol sequence are also described.

Abstract: A mobile device that generates and transmits a human-inaudible acoustic signal, which encodes a symbol sequence representing a binary message, for delivery as audio content, is disclosed. The mobile device encodes the binary message into a sequence of symbols that are each associated with frequency characteristics and generates and transmits the human-inaudible acoustic signal, based on the frequency characteristics of the symbols. A further mobile device that receives and decodes a human-inaudible acoustic signal, which encodes a symbol sequence representing a binary message, embedded within audio content, is disclosed. The mobile device repeatedly performs a frequency domain transformation of samples of the signal to generate a symbol sequence, and performs error correction decoding upon the symbol sequence to determine the validity of the symbol sequence.