NENA officials clarify terms of wireless 911 location deal with carriers

In addition, the NENA/APCO agreement with the four nationwide wireless carriers aims to take some of the guesswork out of the compliance process, as well. Instead of relying on carrier tests of location-based technology, the new agreement calls for data from actual 911 calls to be used as a benchmark.

“The commission’s proposal was focused on 911 in carrier tests,” Forgety said. “In other words, the outdoor rules are based on the carriers going out and drive-testing their networks—that’s how they confirm their compliance fractions. That has led to a lot of frustration on the part of public-safety folks who say, ‘We’re in a world now where it’s possible to collect live call data. Why aren’t we checking on that?’

“The agreement moves us away from that test protocol and into a world of real, live 911 call data.”

But the actual 911 call data would be used only after location-based technologies have been tested and proven effective in new testbeds proposed in the agreement. With this in mind, it is important that the testbed environments be established in a way to reflect real-world environments as closely as possible, Forgety said.

“For example, we believe that about 70% of all wireless 911 calls actually come from indoors. Let’s say that proves to be true,” Forgety said. “On that basis, the testbed would shoot for 70% of its test calls coming from indoor locations, and that would form the basis of that performance characterization.

“So, if a given technology performs terribly indoors, then for those 70% of the calls, it probably won’t meet the definition of a high-accuracy location technology, and so it would get discounted heavily in calculating the carrier’s compliance fractions.”

In the wake of the NENA/APCO deal with the carriers being announced, many in the public-safety community expressed concerns about the compliance metrics included in the agreement. While the accord was aimed at improving 911 location for indoor wireless calls, the benchmark metrics only addressed all wireless calls and did not specify indoor wireless calls.

Forgety said the reason for this is simple: there is no way to distinguish an indoor wireless 911 call from an outdoor wireless 911 call.

“I think that’s a subtle-but-key difference between the commission’s proposal and the consensus agreement,” he said. “In live call data, we have no ability to determine whether an individual call was outdoors or indoors.

“So, we had to build a metric that was based on the fact that there is going to be a blend of outdoor and indoor calls in that data. We do take into account very carefully the fact that we can’t know that [a call was from indoors or outdoors] in the agreement.”

This reality is reflected in the compliance metrics that carriers would have to meet, under the terms of the agreement.