Device-based hybrid solutions that utilize Wi-Fi and Bluetooth signals appear to be the most promising to help locate people using a cell phone to call 911 from inside buildings within dense urban environments, according to initial results from the 911 Location Technologies Test Bed.

Matthew Gerst, CTIA’s assistant vice president of regulatory affairs, said the first two stages of testing have been completed at independent test beds in Atlanta and San Francisco. The test-bed program was established after the FCC approved rules in 2015 that created benchmarks for locating 911 callers using wireless devices indoors, as well as outdoors.

“Existing technologies that we’re using today—like GPS and other network-based technologies—performed well indoors in urban, surburban and rural areas,” Gerst said during an interview with IWCE’s Urgent Communications. “But they’re challenged indoors in dense urban areas, and that’s where we saw this device-based hybrid solution hold the most promise for improving indoor location accuracy.”

Stage 1 of the test-bed program examined the performance of carriers’ existing location technologies, Gerst said.

“One of the things that the carriers tested in Stage 1 was the idea of a device-based hybrid solution,” he said. “If the handset has its own location-information capabilities—scanning for Wi-Fi access points, for example—the carriers want to utilize that information for 911. They’re already starting to begin to use that in their networks.

Stage 2 of the program included testing of location technologies that exist today outside of carrier networks, such as dedicated 911 solutions, Gerst said.

Stage 3 is “more about looking at these smaller-scale, localized deployment solutions to make sure that we’re not leaving any stone unturned as we look for location technologies that could be used for 911,” Gerst said, noting that the goal is “to see if they can be scaled up to be used for 911 nationally.”

Stage 1 and Stage 2 of the test-bed program have been completed. Stage 3 testing is expected to begin during the middle of year, and vendors are being asked to submit their technologies for consideration, Gerst said. Vendors can submit an application to participate in Stage 3 testing at the 911 Location Technologies Test Bed web site by April 3.

Although testing for Stage 1 and Stage 2 was conducted in Atlanta and San Francisco, Stage 3 testing locations have not been determined yet, Gerst said. Testing sites could be chosen to make it more convenient for vendors, he said.

“There’s no cost for the [Stage 3] application,” Gerst said. “But, if you are accepted into the test bed, we do expect you to bear the cost of the testing itself. That includes the boots on the ground.

Another aspect of the FCC’s 911 location order is that it calls for carriers to provide public-safety entities with vertical location information about emergency callers—the so-called Z axis. Although some Z-axis performance information is being gathered within the first three test-bed stages, there will a separate test that will focus on Z-axis location, Gerst said.

“We hope to conduct that test later in this year, if not very early next year, because the carriers are required to come up with a proposed metric and deliver that to the FCC in August 2018,” he said.