Patent ID: 8140016
Filing Date: 2012-03-20
Classification: G01S,H04B,H04L

Abstract:
1. A communication terminal comprising: a radio frequency (RF) transceiver that comprises a Bluetooth transceiver that operates to establish a Bluetooth communication network with another communication terminal across a wireless communication network that uses RF communication signals with known timing characteristics; a microphone that generates a microphone signal that is indicative of incident acoustic signals; a controller that is configured to synchronize a clock in response to frame timing of the Bluetooth communication network, to transmit through the Bluetooth transceiver to the other communication terminal a message that identifies a Bluetooth signaling frame number that will serve as a known timing event that is to trigger the other communication terminal to begin generation of an acoustic signal, and is configured to determine a propagation time of the acoustic signal from the other communication terminal to the microphone based on a difference between timing of occurrence of the identified Bluetooth signaling frame number and the acoustic signal receipt time, and to determine an acoustic range to the other communication terminal in response to the propagation time of the acoustic signal.