Wireless geolocation

Abstract

Before wireless phones became commonplace, the United States Federal Communications Commission (FCC) recognized both the need and benefit of establishing a nationwide emergency number, 911, and the capability to route the call to the nearest public safety answering point (PSAP) while providing the calling number and its location. The first U.S. landline 911 call actually occurred at 2:00 p.m. on Friday, 16 February 1968, in Haleyville, Alabama, on the Alabama Telephone Company's network [1]. However, it was not until 1972 that the FCC recommended that 911 be implemented nationwide. Subsequently, many counties implemented landline 911 systems [1]. Once deployed, this resulted in a monumental improvement in the delivery of emergency services to those in need. Countless lives were saved because emergency service providers were able to provide help expeditiously. At this time, wireless phones were in their infancy. They were big, bulky, and expensive. Originally, it was never anticipated that they would deliver the cost efficiency, capability, and popularity that they have achieved today. In addition, it is a global phenomenon with many citizens of some countries possessing more than one mobile phone resulting in the wireless penetration in those countries exceeding 100%. As the number of U.S. wireless subscribers increased, it became apparent that the time would soon come when the number of emergency calls originating from mobile phones would exceed the number that originated from landline phones. One of the key benefits of the 911 capability was the almost instantaneous location determination of the landline phone that originated the call. With this information, emergency service providers could efficiently provide emergency services when and where needed. However, the "anytime, anywhere" communications convenience of wireless phones meant that mobile phone users were untethered or, in other words, not tied to a specific location. With this wireless revolution, the U.S. emergency service providers would lose a key piece of information---the location of the caller in distress---unless something was done.