FCC E911 location ruling the first step in journey to improved emergency-response times

Because OTDOA is limited, E911 deployment may require additional techniques, such as AoA. When used with OTDOA, AoA can reduce uncertainty and decrease response time to contact. AoA + OTDOA systems require installing specialized antenna arrays. Commonly referred to as “triangulation,” standalone AoA requires at least three tower antenna sites. AoA + OTDOA requires at least two tower antenna sites and works best with three or more.

Target location inaccuracy caused by incorrect tower antenna location data for OTDOA systems and/or inaccurate azimuthal alignment for AoA systems has real consequences beyond failing to meet FCC E911 mandates. A Columbia University study found that, on average, a one-minute reduction in EMS response time equals a 17% decrease in the likelihood of 90-day mortality, the medical standard for measuring effectiveness of treatment or intervention. Approximately 25 million people call for an ambulance each year. Using rough but reasonable assumptions, it can be estimated that improved location accuracy that reduces EMS response time by one minute can save over 10,000 lives annually and have a societal benefit of more than $92 billion. 

Using proper alignment tools , such as those outlined in a recently published E911 white paper, that can measure and record latitude and longitude to within 30 centimeters can improve response time and save more lives. When used to align the azimuth of a sectored cellular antenna, ±0.3° RMS can be provided. The appropriate tools can ensure proper azimuth alignment and record more accurate antenna location data for PSAP and RF databases. Benefits include fewer periodic adjustments, and less likelihood of costly and time-consuming system troubleshooting and retesting.

Providing PSAPs with a highly accurate database of tower antenna locations is critical to meeting FCC E911mandates. Accurate azimuthal alignment of antennas is also essential for system performance. Improving antenna position data capture is one of the solutions to improving E911 network-location-based determinations. Achieving these success metrics will create a system that better serves an increasingly mobile community with accuracy and lowered public-safety response times.

John Vetter is the vice president of business development for Sunsight Instruments. John has 20+ years’ experience in RF engineering, wireless-network design, deployment, and post network performance/optimization.  As a senior-level manager, he managed the engineering and operations departments of MetroPCS/T-Mobile and Clearwire (now Sprint), working with all major wireless technologies, including 4G.  He has worked on the vendor side for Ericsson and Alcatel-Lucent in similar roles.