An acoustic identification scheme for location systems

Many pervasive computing applications require location awareness in order to successfully integrate technology into our daily lives. A location system consists of a group of sensors that determine the position of a mobile user and provide the user with useful context-specific information. Locating the user requires signal exchanges between the user's mobile device and the sensors. This paper considers an acoustic-based location system for pervasive computing applications. The system is comprised of a set of microphones connected to a central server. Mobile users produce acoustic signals through standard speakers, which are already available in most mobile devices, to perform location operations through the system. We focus on the design of robust acoustic signals using multi-frequency symbols that serve both in locating and uniquely identifying the user. We conduct experiments at distances between 1 and 17 ft to explore the ability of the server to recognize and decode signals originated by different users in the same general area.