Localization of handheld devices inside vehicles using audio masking

This paper addresses the problem of locating a handheld device (a smartphone or a tablet) inside a car. Based on the location of the device in the car, one can determine whether the device is being used by a driver or not so that a software can enable or disable certain features and functions of the device to reduce the distraction to the driver. We provide several predesigned audio signals to play from the car audio system that can be received by a handheld device inside the car. Using some prior knowledge of the predesigned audio signal, the handheld device can post-process the received signal in order to locate its position. Another key element in this paper is the technique to make the audio signal inaudible from users. Two audio hiding methods are proposed that are based on audio masking and playing in the out-of-hearing band.