When a person calls an emergency number, such as 9-1-1, in the U.S. the location of the caller must be provided to the network. This information is used for two purposes: First, to route the call to the appropriate answering point; Second, to display the caller’s location to the operator dispatching first-responders. When the call comes from a mobile device inside a building, the operator and first responders need more information than latitude and longitude and/or street address to find the caller. They need accurate indoor location – a floor and room number for example. This paper describes a proof of concept system that provides the floor and room number, as well as the street address of a caller. The system was developed in response to the ‘Roadmap for Improving E911 Location Accuracy”, created by an alliance of the Association of Public-Safety Communications Officials-International (APCO), the National Emergency Numbers Association (NENA) and four national wireless carriers, AT&T, Sprint, T-Mobile and Verizon. The system described in this paper is integrated with a replica of an Emergency Services IP Backbone Network (ESInet) on a test-bed in the IIT Real-Time Communications Lab. The ESInet is specified by NENA for the carriage of Next Generation 9-1-1 (NG9-1-1) calls.
The system consists of the following four components: (1) A smartphone application that detects the emergency call, obtains the location of the caller, and forwards the call, including location information, to the answering point; (2) An array of Bluetooth Low Energy (BLE) devices that are deployed on the inside walls of a building at selected locations; (3) A database that contains the location of the BLE devices; (4) A Location Server capable of querying the database to discover the location of particular BLE devices, and of using the location information thus obtained to calculate the location of the caller, format this location, and send the formatted information to the smartphone. 
To demonstrate the ability of this system to integrate with an Emergency Services IP Backbone Network (ESInet), as specified by the National Emergency Numbers Association (NENA) for the carriage of Next Generation 9-1-1 (NG9-1-1) calls, the calls generated by the proof of concept system are routed to a test-bed in the IIT Real-Time Communications Lab (RTC Lab) that replicates the functions of an ESINet.
The mobile application is built on the Android OS and includes the functions of a SIP User Agent [FN SIP UA] provided by the opensource SIPdroid distribution. The iBeacons in the Bluetooth array operate in ‘advertise’ mode only, broadcasting their Major and Minor identifiers every half second. The database is built using MySQL and the location server is a Linux system that includes a node.js module.
For further information on this project, including further descriptions of the service, array, location server, android application, algorithms, experiments and tests, discussion of related work, associated operations and maintenance systems, conclusions and next steps, please visit http://appliedtech.iit.edu/rtc-lab or contact Director, Real-Time Communications Lab of Illinois Institute of Technology/Adjunct Industry Professor of Information Technology and Management, Carol Davids at davids@iit.edu.
