Detecting proximity of devices based on transmission of inaudible sound signatures in the speech band

摘要

A communication device detects sound with a microphone to produce a sound signal representative of the sound and searches the sound signal for unique inaudible sound signatures associated with a group identifier. Each sound signature identifies a respective communication device. Each sound signature is in an audible frequency band but masked to be imperceptible. If any of the sound signatures are determined to be present in the sound signal, the communication device selects one based on predetermined criteria associated with the group identifier.