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In 1996, the FCC issued a Report and Order requiring all wireless carriers and cell phone manufacturers to provide the capability for automatically identifying to emergency dispatchers the location from which a wireless call is being made. At that time, implementation of the E911 requirements was divided into two phases. Phase I required wireless carriers to deliver to the emergency dispatcher the telephone number of a wireless handset originating a 911 call, as well as the location of the cell site or base station receiving the 911 call, which provides a rough indication of the caller's location. This phase was implemented by the end of 1998.

Phase II requires carriers to deliver more specific latitude and longitude location information, known as Automatic Location Identification (ALI), to the dispatcher. There were a number of interim milestones for full implementation of this phase, beginning in March 2001 and ending with complete implementation by the end of 2005. These requirements were not fully met, and the FCC has fined a number of national operators in recent years for failure to meet their E-911 obligations. Rapidly evolving and mixed technologies, geographical terrain differences, infrastructure issues, and the increase in the number of people using mobile phones to meet more of their communication needs all added to the difficulty in implementing this requirement.

In September 2007, the FCC issued a new E-911 location decision and ordered operators to meet interim and annual benchmarks during the next five years to ensure full compliance with these new requirements by September 11, 2012. These regulations, which require location of emergency callers within 50-300 yards depending on the technology used, are not entirely workable given the difficulties in geography and systems. Several companies banded together and obtained a stay on implementation of this decision in the courts pending the outcome of litigation. At the end of August 2008, the FCC has agreed to voluntarily withdraw the new regulations, citing the Public Safety community's agreement that more lax regulations will meet their needs. Federal telecom policymakers want to examine whether there should be one, technology-neutral standard for wireless E-911 accuracy, which could give substantial commercial advantages to some of the companies that have been working on technology that could meet such a standard.

Providing the E911 service in a manner that is economically feasible for the carriers has proven to be quite a challenge! The headaches aren't over yet -- for example, many of the location technologies use GPS. This causes lots of concern over the use of UWB (ultra wideband), and possible concerns with interference between UWB devices and GPS. You can read about this issue in depth, and find out more about GPS in our UWB and GPS pages listed under Related Information on SSS Online below.

Take some time to explore the articles, resources, references and links below to learn more about this rapidly evolving subject!

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  Related Information on SSS Online

Wireless Glossary

Ultra-Wideband News

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CDMA Stuff Page

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Third Generation Wireless Info Page

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News Articles on E911

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Articles from SSS Online's Technical Briefings Archive

ADOBE Acrobat (.pdf) Files Relating to E911:
Various Authors, Paper -- "Providing Universal Location Services Using a Wireless E911 Location Network" -- (~135K) -- (Thanks IEEE!).
Caffery and Stuber's April 1998 Paper (Georga Institute of Technology) -- "Overview of Radiolocation in CDMA Cellular Systems" -- (~88K) -- (Thanks IEEE!).
Prof. Randy H. Katz' (UCB) Briefing -- "CS294-7: Cellular Telephony" -- (~489K).
Phil Flikkema's (USF) Briefing -- "Introduction to Spread Spectrum" -- (~110K).

Read ICUCOM's ACOLADE IS-95 CDMA Library Description
(with a Great intro to IS-95 in the first few pages).

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OTHER E911 Resources:

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